qemu-e2k/scripts/dump-guest-memory.py

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"""
This python script adds a new gdb command, "dump-guest-memory". It
should be loaded with "source dump-guest-memory.py" at the (gdb)
prompt.
Copyright (C) 2013, Red Hat, Inc.
Authors:
Laszlo Ersek <lersek@redhat.com>
Janosch Frank <frankja@linux.vnet.ibm.com>
This work is licensed under the terms of the GNU GPL, version 2 or later. See
the COPYING file in the top-level directory.
"""
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
import ctypes
import struct
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
try:
UINTPTR_T = gdb.lookup_type("uintptr_t")
except Exception as inst:
raise gdb.GdbError("Symbols must be loaded prior to sourcing dump-guest-memory.\n"
"Symbols may be loaded by 'attach'ing a QEMU process id or by "
"'load'ing a QEMU binary.")
TARGET_PAGE_SIZE = 0x1000
TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
# Special value for e_phnum. This indicates that the real number of
# program headers is too large to fit into e_phnum. Instead the real
# value is in the field sh_info of section 0.
PN_XNUM = 0xFFFF
EV_CURRENT = 1
ELFCLASS32 = 1
ELFCLASS64 = 2
ELFDATA2LSB = 1
ELFDATA2MSB = 2
ET_CORE = 4
PT_LOAD = 1
PT_NOTE = 4
EM_386 = 3
EM_PPC = 20
EM_PPC64 = 21
EM_S390 = 22
EM_AARCH = 183
EM_X86_64 = 62
VMCOREINFO_FORMAT_ELF = 1
def le16_to_cpu(val):
return struct.unpack("<H", struct.pack("=H", val))[0]
def le32_to_cpu(val):
return struct.unpack("<I", struct.pack("=I", val))[0]
def le64_to_cpu(val):
return struct.unpack("<Q", struct.pack("=Q", val))[0]
class ELF(object):
"""Representation of a ELF file."""
def __init__(self, arch):
self.ehdr = None
self.notes = []
self.segments = []
self.notes_size = 0
self.endianness = None
self.elfclass = ELFCLASS64
if arch == 'aarch64-le':
self.endianness = ELFDATA2LSB
self.elfclass = ELFCLASS64
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_AARCH
elif arch == 'aarch64-be':
self.endianness = ELFDATA2MSB
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_AARCH
elif arch == 'X86_64':
self.endianness = ELFDATA2LSB
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_X86_64
elif arch == '386':
self.endianness = ELFDATA2LSB
self.elfclass = ELFCLASS32
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_386
elif arch == 's390':
self.endianness = ELFDATA2MSB
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_S390
elif arch == 'ppc64-le':
self.endianness = ELFDATA2LSB
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_PPC64
elif arch == 'ppc64-be':
self.endianness = ELFDATA2MSB
self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
self.ehdr.e_machine = EM_PPC64
else:
raise gdb.GdbError("No valid arch type specified.\n"
"Currently supported types:\n"
"aarch64-be, aarch64-le, X86_64, 386, s390, "
"ppc64-be, ppc64-le")
self.add_segment(PT_NOTE, 0, 0)
def add_note(self, n_name, n_desc, n_type):
"""Adds a note to the ELF."""
note = get_arch_note(self.endianness, len(n_name), len(n_desc))
note.n_namesz = len(n_name) + 1
note.n_descsz = len(n_desc)
note.n_name = n_name.encode()
note.n_type = n_type
# Desc needs to be 4 byte aligned (although the 64bit spec
# specifies 8 byte). When defining n_desc as uint32 it will be
# automatically aligned but we need the memmove to copy the
# string into it.
ctypes.memmove(note.n_desc, n_desc.encode(), len(n_desc))
self.notes.append(note)
self.segments[0].p_filesz += ctypes.sizeof(note)
self.segments[0].p_memsz += ctypes.sizeof(note)
def add_vmcoreinfo_note(self, vmcoreinfo):
"""Adds a vmcoreinfo note to the ELF dump."""
# compute the header size, and copy that many bytes from the note
header = get_arch_note(self.endianness, 0, 0)
ctypes.memmove(ctypes.pointer(header),
vmcoreinfo, ctypes.sizeof(header))
if header.n_descsz > 1 << 20:
print('warning: invalid vmcoreinfo size')
return
# now get the full note
note = get_arch_note(self.endianness,
header.n_namesz - 1, header.n_descsz)
ctypes.memmove(ctypes.pointer(note), vmcoreinfo, ctypes.sizeof(note))
self.notes.append(note)
self.segments[0].p_filesz += ctypes.sizeof(note)
self.segments[0].p_memsz += ctypes.sizeof(note)
def add_segment(self, p_type, p_paddr, p_size):
"""Adds a segment to the elf."""
phdr = get_arch_phdr(self.endianness, self.elfclass)
phdr.p_type = p_type
phdr.p_paddr = p_paddr
phdr.p_vaddr = p_paddr
phdr.p_filesz = p_size
phdr.p_memsz = p_size
self.segments.append(phdr)
self.ehdr.e_phnum += 1
def to_file(self, elf_file):
"""Writes all ELF structures to the passed file.
Structure:
Ehdr
Segment 0:PT_NOTE
Segment 1:PT_LOAD
Segment N:PT_LOAD
Note 0..N
Dump contents
"""
elf_file.write(self.ehdr)
off = ctypes.sizeof(self.ehdr) + \
len(self.segments) * ctypes.sizeof(self.segments[0])
for phdr in self.segments:
phdr.p_offset = off
elf_file.write(phdr)
off += phdr.p_filesz
for note in self.notes:
elf_file.write(note)
def get_arch_note(endianness, len_name, len_desc):
"""Returns a Note class with the specified endianness."""
if endianness == ELFDATA2LSB:
superclass = ctypes.LittleEndianStructure
else:
superclass = ctypes.BigEndianStructure
len_name = len_name + 1
class Note(superclass):
"""Represents an ELF note, includes the content."""
_fields_ = [("n_namesz", ctypes.c_uint32),
("n_descsz", ctypes.c_uint32),
("n_type", ctypes.c_uint32),
("n_name", ctypes.c_char * len_name),
("n_desc", ctypes.c_uint32 * ((len_desc + 3) // 4))]
return Note()
class Ident(ctypes.Structure):
"""Represents the ELF ident array in the ehdr structure."""
_fields_ = [('ei_mag0', ctypes.c_ubyte),
('ei_mag1', ctypes.c_ubyte),
('ei_mag2', ctypes.c_ubyte),
('ei_mag3', ctypes.c_ubyte),
('ei_class', ctypes.c_ubyte),
('ei_data', ctypes.c_ubyte),
('ei_version', ctypes.c_ubyte),
('ei_osabi', ctypes.c_ubyte),
('ei_abiversion', ctypes.c_ubyte),
('ei_pad', ctypes.c_ubyte * 7)]
def __init__(self, endianness, elfclass):
self.ei_mag0 = 0x7F
self.ei_mag1 = ord('E')
self.ei_mag2 = ord('L')
self.ei_mag3 = ord('F')
self.ei_class = elfclass
self.ei_data = endianness
self.ei_version = EV_CURRENT
def get_arch_ehdr(endianness, elfclass):
"""Returns a EHDR64 class with the specified endianness."""
if endianness == ELFDATA2LSB:
superclass = ctypes.LittleEndianStructure
else:
superclass = ctypes.BigEndianStructure
class EHDR64(superclass):
"""Represents the 64 bit ELF header struct."""
_fields_ = [('e_ident', Ident),
('e_type', ctypes.c_uint16),
('e_machine', ctypes.c_uint16),
('e_version', ctypes.c_uint32),
('e_entry', ctypes.c_uint64),
('e_phoff', ctypes.c_uint64),
('e_shoff', ctypes.c_uint64),
('e_flags', ctypes.c_uint32),
('e_ehsize', ctypes.c_uint16),
('e_phentsize', ctypes.c_uint16),
('e_phnum', ctypes.c_uint16),
('e_shentsize', ctypes.c_uint16),
('e_shnum', ctypes.c_uint16),
('e_shstrndx', ctypes.c_uint16)]
def __init__(self):
super(superclass, self).__init__()
self.e_ident = Ident(endianness, elfclass)
self.e_type = ET_CORE
self.e_version = EV_CURRENT
self.e_ehsize = ctypes.sizeof(self)
self.e_phoff = ctypes.sizeof(self)
self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianness, elfclass))
self.e_phnum = 0
class EHDR32(superclass):
"""Represents the 32 bit ELF header struct."""
_fields_ = [('e_ident', Ident),
('e_type', ctypes.c_uint16),
('e_machine', ctypes.c_uint16),
('e_version', ctypes.c_uint32),
('e_entry', ctypes.c_uint32),
('e_phoff', ctypes.c_uint32),
('e_shoff', ctypes.c_uint32),
('e_flags', ctypes.c_uint32),
('e_ehsize', ctypes.c_uint16),
('e_phentsize', ctypes.c_uint16),
('e_phnum', ctypes.c_uint16),
('e_shentsize', ctypes.c_uint16),
('e_shnum', ctypes.c_uint16),
('e_shstrndx', ctypes.c_uint16)]
def __init__(self):
super(superclass, self).__init__()
self.e_ident = Ident(endianness, elfclass)
self.e_type = ET_CORE
self.e_version = EV_CURRENT
self.e_ehsize = ctypes.sizeof(self)
self.e_phoff = ctypes.sizeof(self)
self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianness, elfclass))
self.e_phnum = 0
# End get_arch_ehdr
if elfclass == ELFCLASS64:
return EHDR64()
else:
return EHDR32()
def get_arch_phdr(endianness, elfclass):
"""Returns a 32 or 64 bit PHDR class with the specified endianness."""
if endianness == ELFDATA2LSB:
superclass = ctypes.LittleEndianStructure
else:
superclass = ctypes.BigEndianStructure
class PHDR64(superclass):
"""Represents the 64 bit ELF program header struct."""
_fields_ = [('p_type', ctypes.c_uint32),
('p_flags', ctypes.c_uint32),
('p_offset', ctypes.c_uint64),
('p_vaddr', ctypes.c_uint64),
('p_paddr', ctypes.c_uint64),
('p_filesz', ctypes.c_uint64),
('p_memsz', ctypes.c_uint64),
('p_align', ctypes.c_uint64)]
class PHDR32(superclass):
"""Represents the 32 bit ELF program header struct."""
_fields_ = [('p_type', ctypes.c_uint32),
('p_offset', ctypes.c_uint32),
('p_vaddr', ctypes.c_uint32),
('p_paddr', ctypes.c_uint32),
('p_filesz', ctypes.c_uint32),
('p_memsz', ctypes.c_uint32),
('p_flags', ctypes.c_uint32),
('p_align', ctypes.c_uint32)]
# End get_arch_phdr
if elfclass == ELFCLASS64:
return PHDR64()
else:
return PHDR32()
def int128_get64(val):
"""Returns low 64bit part of Int128 struct."""
try:
assert val["hi"] == 0
return val["lo"]
except gdb.error:
u64t = gdb.lookup_type('uint64_t').array(2)
u64 = val.cast(u64t)
if sys.byteorder == 'little':
assert u64[1] == 0
return u64[0]
else:
assert u64[0] == 0
return u64[1]
def qlist_foreach(head, field_str):
"""Generator for qlists."""
var_p = head["lh_first"]
while var_p != 0:
var = var_p.dereference()
var_p = var[field_str]["le_next"]
yield var
def qemu_map_ram_ptr(block, offset):
"""Returns qemu vaddr for given guest physical address."""
return block["host"] + offset
def memory_region_get_ram_ptr(memory_region):
if memory_region["alias"] != 0:
return (memory_region_get_ram_ptr(memory_region["alias"].dereference())
+ memory_region["alias_offset"])
return qemu_map_ram_ptr(memory_region["ram_block"], 0)
def get_guest_phys_blocks():
"""Returns a list of ram blocks.
Each block entry contains:
'target_start': guest block phys start address
'target_end': guest block phys end address
'host_addr': qemu vaddr of the block's start
"""
guest_phys_blocks = []
print("guest RAM blocks:")
print("target_start target_end host_addr message "
"count")
print("---------------- ---------------- ---------------- ------- "
"-----")
current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
current_map = current_map_p.dereference()
# Conversion to int is needed for python 3
# compatibility. Otherwise range doesn't cast the value itself and
# breaks.
for cur in range(int(current_map["nr"])):
flat_range = (current_map["ranges"] + cur).dereference()
memory_region = flat_range["mr"].dereference()
# we only care about RAM
if (not memory_region["ram"] or
memory_region["ram_device"] or
memory_region["nonvolatile"]):
continue
section_size = int128_get64(flat_range["addr"]["size"])
target_start = int128_get64(flat_range["addr"]["start"])
target_end = target_start + section_size
host_addr = (memory_region_get_ram_ptr(memory_region)
+ flat_range["offset_in_region"])
predecessor = None
# find continuity in guest physical address space
if len(guest_phys_blocks) > 0:
predecessor = guest_phys_blocks[-1]
predecessor_size = (predecessor["target_end"] -
predecessor["target_start"])
# the memory API guarantees monotonically increasing
# traversal
assert predecessor["target_end"] <= target_start
# we want continuity in both guest-physical and
# host-virtual memory
if (predecessor["target_end"] < target_start or
predecessor["host_addr"] + predecessor_size != host_addr):
predecessor = None
if predecessor is None:
# isolated mapping, add it to the list
guest_phys_blocks.append({"target_start": target_start,
"target_end": target_end,
"host_addr": host_addr})
message = "added"
else:
# expand predecessor until @target_end; predecessor's
# start doesn't change
predecessor["target_end"] = target_end
message = "joined"
print("%016x %016x %016x %-7s %5u" %
(target_start, target_end, host_addr.cast(UINTPTR_T),
message, len(guest_phys_blocks)))
return guest_phys_blocks
# The leading docstring doesn't have idiomatic Python formatting. It is
# printed by gdb's "help" command (the first line is printed in the
# "help data" summary), and it should match how other help texts look in
# gdb.
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
class DumpGuestMemory(gdb.Command):
"""Extract guest vmcore from qemu process coredump.
The two required arguments are FILE and ARCH:
FILE identifies the target file to write the guest vmcore to.
ARCH specifies the architecture for which the core will be generated.
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
This GDB command reimplements the dump-guest-memory QMP command in
python, using the representation of guest memory as captured in the qemu
coredump. The qemu process that has been dumped must have had the
command line option "-machine dump-guest-core=on" which is the default.
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
For simplicity, the "paging", "begin" and "end" parameters of the QMP
command are not supported -- no attempt is made to get the guest's
internal paging structures (ie. paging=false is hard-wired), and guest
memory is always fully dumped.
Currently aarch64-be, aarch64-le, X86_64, 386, s390, ppc64-be,
ppc64-le guests are supported.
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
The CORE/NT_PRSTATUS and QEMU notes (that is, the VCPUs' statuses) are
not written to the vmcore. Preparing these would require context that is
only present in the KVM host kernel module when the guest is alive. A
fake ELF note is written instead, only to keep the ELF parser of "crash"
happy.
Dependent on how busted the qemu process was at the time of the
coredump, this command might produce unpredictable results. If qemu
deliberately called abort(), or it was dumped in response to a signal at
a halfway fortunate point, then its coredump should be in reasonable
shape and this command should mostly work."""
def __init__(self):
super(DumpGuestMemory, self).__init__("dump-guest-memory",
gdb.COMMAND_DATA,
gdb.COMPLETE_FILENAME)
self.elf = None
self.guest_phys_blocks = None
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
def dump_init(self, vmcore):
"""Prepares and writes ELF structures to core file."""
# Needed to make crash happy, data for more useful notes is
# not available in a qemu core.
self.elf.add_note("NONE", "EMPTY", 0)
# We should never reach PN_XNUM for paging=false dumps,
# there's just a handful of discontiguous ranges after
# merging.
# The constant is needed to account for the PT_NOTE segment.
phdr_num = len(self.guest_phys_blocks) + 1
assert phdr_num < PN_XNUM
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
for block in self.guest_phys_blocks:
block_size = block["target_end"] - block["target_start"]
self.elf.add_segment(PT_LOAD, block["target_start"], block_size)
self.elf.to_file(vmcore)
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
def dump_iterate(self, vmcore):
"""Writes guest core to file."""
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
qemu_core = gdb.inferiors()[0]
for block in self.guest_phys_blocks:
cur = block["host_addr"]
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
left = block["target_end"] - block["target_start"]
print("dumping range at %016x for length %016x" %
(cur.cast(UINTPTR_T), left))
while left > 0:
chunk_size = min(TARGET_PAGE_SIZE, left)
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
chunk = qemu_core.read_memory(cur, chunk_size)
vmcore.write(chunk)
cur += chunk_size
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
left -= chunk_size
def phys_memory_read(self, addr, size):
qemu_core = gdb.inferiors()[0]
for block in self.guest_phys_blocks:
if block["target_start"] <= addr \
and addr + size <= block["target_end"]:
haddr = block["host_addr"] + (addr - block["target_start"])
return qemu_core.read_memory(haddr, size)
return None
def add_vmcoreinfo(self):
if gdb.lookup_symbol("vmcoreinfo_realize")[0] is None:
return
vmci = 'vmcoreinfo_realize::vmcoreinfo_state'
if not gdb.parse_and_eval("%s" % vmci) \
or not gdb.parse_and_eval("(%s)->has_vmcoreinfo" % vmci):
return
fmt = gdb.parse_and_eval("(%s)->vmcoreinfo.guest_format" % vmci)
addr = gdb.parse_and_eval("(%s)->vmcoreinfo.paddr" % vmci)
size = gdb.parse_and_eval("(%s)->vmcoreinfo.size" % vmci)
fmt = le16_to_cpu(fmt)
addr = le64_to_cpu(addr)
size = le32_to_cpu(size)
if fmt != VMCOREINFO_FORMAT_ELF:
return
vmcoreinfo = self.phys_memory_read(addr, size)
if vmcoreinfo:
self.elf.add_vmcoreinfo_note(bytes(vmcoreinfo))
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
def invoke(self, args, from_tty):
"""Handles command invocation from gdb."""
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
# Unwittingly pressing the Enter key after the command should
# not dump the same multi-gig coredump to the same file.
self.dont_repeat()
argv = gdb.string_to_argv(args)
if len(argv) != 2:
raise gdb.GdbError("usage: dump-guest-memory FILE ARCH")
self.elf = ELF(argv[1])
self.guest_phys_blocks = get_guest_phys_blocks()
self.add_vmcoreinfo()
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
with open(argv[0], "wb") as vmcore:
self.dump_init(vmcore)
self.dump_iterate(vmcore)
Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump When qemu dies unexpectedly, for example in response to an explicit abort() call, or (more importantly) when an external signal is delivered to it that results in a coredump, sometimes it is useful to extract the guest vmcore from the qemu process' memory image. The guest vmcore might help understand an emulation problem in qemu, or help debug the guest. This script reimplements (and cuts many features of) the qmp_dump_guest_memory() command in gdb/Python, https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html working off the saved memory image of the qemu process. The docstring in the patch (serving as gdb help text) describes the limitations relative to the QMP command. Dependencies of qmp_dump_guest_memory() have been reimplemented as needed. I sought to follow the general structure, sticking to original function names where possible. However, keeping it simple prevailed in some places. The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4 (2.6.32-358.el6.x86_64) guest: - The script printed > guest RAM blocks: > target_start target_end host_addr message count > ---------------- ---------------- ---------------- ------- ----- > 0000000000000000 00000000000a0000 00007f95d0000000 added 1 > 00000000000a0000 00000000000b0000 00007f960ac00000 added 2 > 00000000000c0000 00000000000ca000 00007f95d00c0000 added 3 > 00000000000ca000 00000000000cd000 00007f95d00ca000 joined 3 > 00000000000cd000 00000000000d0000 00007f95d00cd000 joined 3 > 00000000000d0000 00000000000f0000 00007f95d00d0000 joined 3 > 00000000000f0000 0000000000100000 00007f95d00f0000 joined 3 > 0000000000100000 0000000030000000 00007f95d0100000 joined 3 > 00000000fc000000 00000000fc800000 00007f960ac00000 added 4 > 00000000fffe0000 0000000100000000 00007f9618800000 added 5 > dumping range at 00007f95d0000000 for length 00000000000a0000 > dumping range at 00007f960ac00000 for length 0000000000010000 > dumping range at 00007f95d00c0000 for length 000000002ff40000 > dumping range at 00007f960ac00000 for length 0000000000800000 > dumping range at 00007f9618800000 for length 0000000000020000 - The vmcore was checked with "readelf", comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- theirs 2013-09-12 17:38:59.797289404 +0200 > +++ mine 2013-09-12 17:39:03.820289404 +0200 > @@ -27,16 +27,16 @@ > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000 > - 0x0000000000000ca0 0x0000000000000ca0 0 > - LOAD 0x0000000000000e30 0x0000000000000000 0x0000000000000000 > + 0x000000000000001c 0x000000000000001c 0 > + LOAD 0x00000000000001ac 0x0000000000000000 0x0000000000000000 > 0x00000000000a0000 0x00000000000a0000 0 > - LOAD 0x00000000000a0e30 0x0000000000000000 0x00000000000a0000 > + LOAD 0x00000000000a01ac 0x0000000000000000 0x00000000000a0000 > 0x0000000000010000 0x0000000000010000 0 > - LOAD 0x00000000000b0e30 0x0000000000000000 0x00000000000c0000 > + LOAD 0x00000000000b01ac 0x0000000000000000 0x00000000000c0000 > 0x000000002ff40000 0x000000002ff40000 0 > - LOAD 0x000000002fff0e30 0x0000000000000000 0x00000000fc000000 > + LOAD 0x000000002fff01ac 0x0000000000000000 0x00000000fc000000 > 0x0000000000800000 0x0000000000800000 0 > - LOAD 0x00000000307f0e30 0x0000000000000000 0x00000000fffe0000 > + LOAD 0x00000000307f01ac 0x0000000000000000 0x00000000fffe0000 > 0x0000000000020000 0x0000000000020000 0 > > There is no dynamic section in this file. > @@ -47,13 +47,6 @@ > > No version information found in this file. > > -Notes at offset 0x00000190 with length 0x00000ca0: > +Notes at offset 0x00000190 with length 0x0000001c: > Owner Data size Description > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - CORE 0x00000150 NT_PRSTATUS (prstatus structure) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > - QEMU 0x000001b0 Unknown note type: (0x00000000) > + NONE 0x00000005 Unknown note type: (0x00000000) - The vmcore was checked with "crash" too, again comparing the results against a vmcore written by qmp_dump_guest_memory(): > --- guest.vmcore.log2 2013-09-12 17:52:27.074289201 +0200 > +++ example.dump.log2 2013-09-12 17:52:15.904289203 +0200 > @@ -22,11 +22,11 @@ > This GDB was configured as "x86_64-unknown-linux-gnu"... > > KERNEL: /usr/lib/debug/lib/modules/2.6.32-358.el6.x86_64/vmlinux > - DUMPFILE: /home/lacos/tmp/guest.vmcore > + DUMPFILE: /home/lacos/tmp/example.dump > CPUS: 4 > - DATE: Thu Sep 12 17:16:11 2013 > - UPTIME: 00:01:09 > -LOAD AVERAGE: 0.07, 0.03, 0.00 > + DATE: Thu Sep 12 17:17:41 2013 > + UPTIME: 00:00:38 > +LOAD AVERAGE: 0.18, 0.05, 0.01 > TASKS: 130 > NODENAME: localhost.localdomain > RELEASE: 2.6.32-358.el6.x86_64 > @@ -38,12 +38,12 @@ > COMMAND: "swapper" > TASK: ffffffff81a8d020 (1 of 4) [THREAD_INFO: ffffffff81a00000] > CPU: 0 > - STATE: TASK_RUNNING (PANIC) > + STATE: TASK_RUNNING (ACTIVE) > + WARNING: panic task not found > > crash> bt > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > - #0 [ffffffff81a01ed0] default_idle at ffffffff8101495d > - #1 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > + #0 [ffffffff81a01ef0] cpu_idle at ffffffff81009fc6 > crash> task ffffffff81a8d020 > PID: 0 TASK: ffffffff81a8d020 CPU: 0 COMMAND: "swapper" > struct task_struct { > @@ -75,7 +75,7 @@ > prev = 0xffffffff81a8d080 > }, > on_rq = 0, > - exec_start = 8618466836, > + exec_start = 7469214014, > sum_exec_runtime = 0, > vruntime = 0, > prev_sum_exec_runtime = 0, > @@ -149,7 +149,7 @@ > }, > tasks = { > next = 0xffff88002d621948, > - prev = 0xffff880029618f28 > + prev = 0xffff880023b74488 > }, > pushable_tasks = { > prio = 140, > @@ -165,7 +165,7 @@ > } > }, > mm = 0x0, > - active_mm = 0xffff88002929b780, > + active_mm = 0xffff8800297eb980, > exit_state = 0, > exit_code = 0, > exit_signal = 0, > @@ -177,7 +177,7 @@ > sched_reset_on_fork = 0, > pid = 0, > tgid = 0, > - stack_canary = 2483693585637059287, > + stack_canary = 7266362296181431986, > real_parent = 0xffffffff81a8d020, > parent = 0xffffffff81a8d020, > children = { > @@ -224,14 +224,14 @@ > set_child_tid = 0x0, > clear_child_tid = 0x0, > utime = 0, > - stime = 3, > + stime = 2, > utimescaled = 0, > - stimescaled = 3, > + stimescaled = 2, > gtime = 0, > prev_utime = 0, > prev_stime = 0, > nvcsw = 0, > - nivcsw = 1000, > + nivcsw = 1764, > start_time = { > tv_sec = 0, > tv_nsec = 0 - <name_dropping>I asked for Dave Anderson's help with verifying the extracted vmcore, and his comments make me think I should post this.</name_dropping> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-12-17 01:37:06 +01:00
DumpGuestMemory()