It can accidentally happen that the faulting insn (the exact instruction
bytes) is repeated a little further on in the trace. This causes that
same instruction to be tagged twice, see example below.
What we want to do, however, is to track back from the end of the whole
disassembly so many lines as the slice which starts with the faulting
instruction is long. This leads us to the actual faulting instruction
and *then* we tag it.
While we're at it, we can drop the sed "g" flag because we address only
this one line.
Also, if we point to an instruction which changes decoding depending on
the slice being objdumped, like a Jcc insn, for example, we do not even
tag it as a faulting instruction because the instruction decode changes
in the second slice but we use that second format as a regex on the
fsrst disassembled buffer and more often than not that instruction
doesn't match.
Again, simply tag the line which is deduced from the original "<>"
marking we've received from the kernel.
This also solves the pathologic issue of multiple tagging like this:
29:* 0f 0b ud2 <-- trapping instruction
2b:* 0f 0b ud2 <-- trapping instruction
2d:* 0f 0b ud2 <-- trapping instruction
Double tagging example:
Code: 34 dd 40 30 ad 81 48 c7 c0 80 f6 00 00 48 8b 3c 30 48 01 c6 b8 ff ff ff ff 48 8d 57 f0 48 39 f7 74 2f 49 8b 4c 24 08 48 8b 47 f0 <48> 39 48 08 75 0e eb 2a 66 90 48 8b 40 f0 48 39 48 08 74 1e 48
All code
========
0: 34 dd xor $0xdd,%al
2: 40 30 ad 81 48 c7 c0 xor %bpl,-0x3f38b77f(%rbp)
9: 80 f6 00 xor $0x0,%dh
c: 00 48 8b add %cl,-0x75(%rax)
f: 3c 30 cmp $0x30,%al
11: 48 01 c6 add %rax,%rsi
14: b8 ff ff ff ff mov $0xffffffff,%eax
19: 48 8d 57 f0 lea -0x10(%rdi),%rdx
1d: 48 39 f7 cmp %rsi,%rdi
20: 74 2f je 0x51
22: 49 8b 4c 24 08 mov 0x8(%r12),%rcx
27: 48 8b 47 f0 mov -0x10(%rdi),%rax
2b:* 48 39 48 08 cmp %rcx,0x8(%rax) <-- trapping instruction
2f: 75 0e jne 0x3f
31: eb 2a jmp 0x5d
33: 66 90 xchg %ax,%ax
35: 48 8b 40 f0 mov -0x10(%rax),%rax
39:* 48 39 48 08 cmp %rcx,0x8(%rax) <-- trapping instruction
3d: 74 1e je 0x5d
3f: 48 rex.W
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When dumping "Code: " sections from an oops, the trapping instruction
%rip points to can be a string copy
2b:* f3 a5 rep movsl %ds:(%rsi),%es:(%rdi)
and the line contain a bunch of ":". Current "cut" selects only the and
the second field output looks funnily overlaid this:
2b:* f3 a5 rep movsl %ds <-- trapping instruction:(%rsi),%es:(%rdi
Fix this by selecting the remaining fields too.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove bashisms to make scripts/decodecode work with other shells.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This patch adds support for decoding ARM oopses to scripts/decodecode.
The following things are handled:
- ARCH and CROSS_COMPILE environment variables are respected.
- The Code: in x86 oopses is in bytes, while it is in either words (4
bytes) or halfwords for ARM.
- Some versions of ARM objdump refuse to disassemble instructions
generated by literal constants (".word 0x..."). The workaround is to
strip the object file first.
- The faulting instruction is marked (liked so) in ARM, but <like so>
in x86.
- ARM mnemonics may include characters such as [] which need to be
escaped before being passed to sed for the "<- trapping instruction"
substitution.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Michal Marek <mmarek@suse.cz>
kerneloops.org has been using an improved "decodecode" script,
specifically it has a special marker that shows which line in the assembly
the oops happened at, like this:
20: 83 e0 03 and $0x3,%eax
23: 09 d8 or %ebx,%eax
25: 85 db test %ebx,%ebx
27: 89 02 mov %eax,(%edx)
29: 74 0f je 0x3a
2b:* 3b 73 04 cmp 0x4(%ebx),%esi <-- trapping instruction
2e: 75 05 jne 0x35
30: 89 53 04 mov %edx,0x4(%ebx)
33: eb 07 jmp 0x3c
35: 89 53 08 mov %edx,0x8(%ebx)
this patch updates the kernel copy to also have this functionality.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Reviewed-by: WANG Cong <wangcong@zeuux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Remove the tmp file when exiting. Noticed by Arjan van de Ven.
Catch mktemp failure and exit with message.
Trap kill or other signals and exit cleanly.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Add info that the Code: bytes line contains <xy> or (wxyz) in some
architecture oops reports and what that means.
Add a script by Andi Kleen that reads the Code: line from an Oops report
file and generates assembly code from the hex bytes.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Borislav Petkov