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197 Commits

Author SHA1 Message Date
Michael Neuling 0d855354ea perf, powerpc: Fix hw breakpoints returning -ENOSPC
I've been trying to get hardware breakpoints with perf to work
on POWER7 but I'm getting the following:

  % perf record -e mem:0x10000000 true

    Error: sys_perf_event_open() syscall returned with 28 (No space left on device).  /bin/dmesg may provide additional information.

    Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?

  true: Terminated

(FWIW adding -a and it works fine)

Debugging it seems that __reserve_bp_slot() is returning ENOSPC
because it thinks there are no free breakpoint slots on this
CPU.

I have a 2 CPUs, so perf userspace is doing two perf_event_open
syscalls to add a counter to each CPU [1].  The first syscall
succeeds but the second is failing.

On this second syscall, fetch_bp_busy_slots() sets slots.pinned
to be 1, despite there being no breakpoint on this CPU.  This is
because the call the task_bp_pinned, checks all CPUs, rather
than just the current CPU. POWER7 only has one hardware
breakpoint per CPU (ie. HBP_NUM=1), so we return ENOSPC.

The following patch fixes this by checking the associated CPU
for each breakpoint in task_bp_pinned.  I'm not familiar with
this code, so it's provided as a reference to the above issue.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Jovi Zhang <bookjovi@gmail.com>
Cc: K Prasad <prasad@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1351268936-2956-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-30 10:07:58 +01:00
Ingo Molnar f38787f4f9 Merge branch 'uprobes/core' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/urgent
Pull various uprobes bugfixes from Oleg Nesterov - mostly race and
failure path fixes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-21 18:18:17 +02:00
Linus Torvalds ade0899b29 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "This tree includes some late late perf items that missed the first
  round:

  tools:

   - Bash auto completion improvements, now we can auto complete the
     tools long options, tracepoint event names, etc, from Namhyung Kim.

   - Look up thread using tid instead of pid in 'perf sched'.

   - Move global variables into a perf_kvm struct, from David Ahern.

   - Hists refactorings, preparatory for improved 'diff' command, from
     Jiri Olsa.

   - Hists refactorings, preparatory for event group viewieng work, from
     Namhyung Kim.

   - Remove double negation on optional feature macro definitions, from
     Namhyung Kim.

   - Remove several cases of needless global variables, on most
     builtins.

   - misc fixes

  kernel:

   - sysfs support for IBS on AMD CPUs, from Robert Richter.

   - Support for an upcoming Intel CPU, the Xeon-Phi / Knights Corner
     HPC blade PMU, from Vince Weaver.

   - misc fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  perf: Fix perf_cgroup_switch for sw-events
  perf: Clarify perf_cpu_context::active_pmu usage by renaming it to ::unique_pmu
  perf/AMD/IBS: Add sysfs support
  perf hists: Add more helpers for hist entry stat
  perf hists: Move he->stat.nr_events initialization to a template
  perf hists: Introduce struct he_stat
  perf diff: Removing the total_period argument from output code
  perf tool: Add hpp interface to enable/disable hpp column
  perf tools: Removing hists pair argument from output path
  perf hists: Separate overhead and baseline columns
  perf diff: Refactor diff displacement possition info
  perf hists: Add struct hists pointer to struct hist_entry
  perf tools: Complete tracepoint event names
  perf/x86: Add support for Intel Xeon-Phi Knights Corner PMU
  perf evlist: Remove some unused methods
  perf evlist: Introduce add_newtp method
  perf kvm: Move global variables into a perf_kvm struct
  perf tools: Convert to BACKTRACE_SUPPORT
  perf tools: Long option completion support for each subcommands
  perf tools: Complete long option names of perf command
  ...
2012-10-13 10:20:11 +09:00
Haggai Eran 6bdb913f0a mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end
In order to allow sleeping during invalidate_page mmu notifier calls, we
need to avoid calling when holding the PT lock.  In addition to its direct
calls, invalidate_page can also be called as a substitute for a change_pte
call, in case the notifier client hasn't implemented change_pte.

This patch drops the invalidate_page call from change_pte, and instead
wraps all calls to change_pte with invalidate_range_start and
invalidate_range_end calls.

Note that change_pte still cannot sleep after this patch, and that clients
implementing change_pte should not take action on it in case the number of
outstanding invalidate_range_start calls is larger than one, otherwise
they might miss a later invalidation.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Cc: Liran Liss <liranl@mellanox.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:58 +09:00
Michel Lespinasse 6b2dbba8b6 mm: replace vma prio_tree with an interval tree
Implement an interval tree as a replacement for the VMA prio_tree.  The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA.  So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.

Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:39 +09:00
Konstantin Khlebnikov 314e51b985 mm: kill vma flag VM_RESERVED and mm->reserved_vm counter
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:19 +09:00
Oleg Nesterov 71434f2fcb uprobes: Fix the racy uprobe->flags manipulation
Multiple threads can manipulate uprobe->flags, this is obviously
unsafe. For example mmap can set UPROBE_COPY_INSN while register
tries to set UPROBE_RUN_HANDLER, the latter can also race with
can_skip_sstep() which clears UPROBE_SKIP_SSTEP.

Change this code to use bitops.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:43 +02:00
Oleg Nesterov 4710f05fd1 uprobes: Fix prepare_uprobe() race with itself
install_breakpoint() is called under mm->mmap_sem, this protects
set_swbp() but not prepare_uprobe(). Two or more different tasks
can call install_breakpoint()->prepare_uprobe() at the same time,
this leads to numerous problems if UPROBE_COPY_INSN is not set.

Just for example, the second copy_insn() can corrupt the already
analyzed/fixuped uprobe->arch.insn and race with handle_swbp().

This patch simply adds uprobe->copy_mutex to serialize this code.
We could probably reuse ->consumer_rwsem, but this would mean that
consumer->handler() can not use mm->mmap_sem, not good.

Note: this is another temporary ugly hack until we move this logic
into uprobe_register().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:43 +02:00
Oleg Nesterov cb9a19fe4a uprobes: Introduce prepare_uprobe()
Preparation. Extract the copy_insn/arch_uprobe_analyze_insn code
from install_breakpoint() into the new helper, prepare_uprobe().

And move uprobe->flags defines from uprobes.h to uprobes.c, nobody
else can use them anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:42 +02:00
Oleg Nesterov 142b18ddc8 uprobes: Fix handle_swbp() vs unregister() + register() race
Strictly speaking this race was added by me in 56bb4cf6. However
I think that this bug is just another indication that we should
move copy_insn/uprobe_analyze_insn code from install_breakpoint()
to uprobe_register(), there are a lot of other reasons for that.
Until then, add a hack to close the race.

A task can hit uprobe U1, but before it calls find_uprobe() this
uprobe can be unregistered *AND* another uprobe U2 can be added to
uprobes_tree at the same inode/offset. In this case handle_swbp()
will use the not-fully-initialized U2, in particular its arch.insn
for xol.

Add the additional !UPROBE_COPY_INSN check into handle_swbp(),
if this flag is not set we simply restart as if the new uprobe was
not inserted yet. This is not very nice, we need barriers, but we
will remove this hack when we change uprobe_register().

Note: with or without this patch install_breakpoint() can race with
itself, yet another reson to kill UPROBE_COPY_INSN altogether. And
even the usage of uprobe->flags is not safe. See the next patches.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:41 +02:00
Oleg Nesterov 076a365b3d uprobes: Do not delete uprobe if uprobe_unregister() fails
delete_uprobe() must not be called if register_for_each_vma(false)
fails to remove all breakpoints, __uprobe_unregister() is correct.
The problem is that register_for_each_vma(false) always returns 0
and thus this logic does not work.

1. Change verify_opcode() to return 0 rather than -EINVAL when
   unregister detects the !is_swbp insn, we can treat this case
   as success and currently unregister paths ignore the error
   code anyway.

2. Change remove_breakpoint() to propagate the error code from
   write_opcode().

3. Change register_for_each_vma(is_register => false) to remove
   as much breakpoints as possible but return non-zero if
   remove_breakpoint() fails at least once.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:41 +02:00
Oleg Nesterov a5f658b71b uprobes: Don't return success if alloc_uprobe() fails
If alloc_uprobe() fails uprobe_register() should return ENOMEM, not 0.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-10-07 21:19:41 +02:00
Peter Zijlstra 95cf59ea72 perf: Fix perf_cgroup_switch for sw-events
Jiri reported that he could trigger the WARN_ON_ONCE() in
perf_cgroup_switch() using sw-events. This is because sw-events share
a cpuctx with multiple PMUs.

Use the ->unique_pmu pointer to limit the pmu iteration to unique
cpuctx instances.

Reported-and-Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-so7wi2zf3jjzrwcutm2mkz0j@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-05 13:59:07 +02:00
Peter Zijlstra 3f1f33206c perf: Clarify perf_cpu_context::active_pmu usage by renaming it to ::unique_pmu
Stephane thought the perf_cpu_context::active_pmu name confusing and
suggested using 'unique_pmu' instead.

This pointer is a pointer to a 'random' pmu sharing the cpuctx
instance, therefore limiting a for_each_pmu loop to those where
cpuctx->unique_pmu matches the pmu we get a loop over unique cpuctx
instances.

Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kxyjqpfj2fn9gt7kwu5ag9ks@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-05 13:59:06 +02:00
Linus Torvalds aab174f0df Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs update from Al Viro:

 - big one - consolidation of descriptor-related logics; almost all of
   that is moved to fs/file.c

   (BTW, I'm seriously tempted to rename the result to fd.c.  As it is,
   we have a situation when file_table.c is about handling of struct
   file and file.c is about handling of descriptor tables; the reasons
   are historical - file_table.c used to be about a static array of
   struct file we used to have way back).

   A lot of stray ends got cleaned up and converted to saner primitives,
   disgusting mess in android/binder.c is still disgusting, but at least
   doesn't poke so much in descriptor table guts anymore.  A bunch of
   relatively minor races got fixed in process, plus an ext4 struct file
   leak.

 - related thing - fget_light() partially unuglified; see fdget() in
   there (and yes, it generates the code as good as we used to have).

 - also related - bits of Cyrill's procfs stuff that got entangled into
   that work; _not_ all of it, just the initial move to fs/proc/fd.c and
   switch of fdinfo to seq_file.

 - Alex's fs/coredump.c spiltoff - the same story, had been easier to
   take that commit than mess with conflicts.  The rest is a separate
   pile, this was just a mechanical code movement.

 - a few misc patches all over the place.  Not all for this cycle,
   there'll be more (and quite a few currently sit in akpm's tree)."

Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
  MAX_LFS_FILESIZE should be a loff_t
  compat: fs: Generic compat_sys_sendfile implementation
  fs: push rcu_barrier() from deactivate_locked_super() to filesystems
  btrfs: reada_extent doesn't need kref for refcount
  coredump: move core dump functionality into its own file
  coredump: prevent double-free on an error path in core dumper
  usb/gadget: fix misannotations
  fcntl: fix misannotations
  ceph: don't abuse d_delete() on failure exits
  hypfs: ->d_parent is never NULL or negative
  vfs: delete surplus inode NULL check
  switch simple cases of fget_light to fdget
  new helpers: fdget()/fdput()
  switch o2hb_region_dev_write() to fget_light()
  proc_map_files_readdir(): don't bother with grabbing files
  make get_file() return its argument
  vhost_set_vring(): turn pollstart/pollstop into bool
  switch prctl_set_mm_exe_file() to fget_light()
  switch xfs_find_handle() to fget_light()
  switch xfs_swapext() to fget_light()
  ...
2012-10-02 20:25:04 -07:00
Linus Torvalds 68d47a137c Merge branch 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup hierarchy update from Tejun Heo:
 "Currently, different cgroup subsystems handle nested cgroups
  completely differently.  There's no consistency among subsystems and
  the behaviors often are outright broken.

  People at least seem to agree that the broken hierarhcy behaviors need
  to be weeded out if any progress is gonna be made on this front and
  that the fallouts from deprecating the broken behaviors should be
  acceptable especially given that the current behaviors don't make much
  sense when nested.

  This patch makes cgroup emit warning messages if cgroups for
  subsystems with broken hierarchy behavior are nested to prepare for
  fixing them in the future.  This was put in a separate branch because
  more related changes were expected (didn't make it this round) and the
  memory cgroup wanted to pull in this and make changes on top."

* 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them
2012-10-02 10:52:28 -07:00
Linus Torvalds 7e92daaefa Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf update from Ingo Molnar:
 "Lots of changes in this cycle as well, with hundreds of commits from
  over 30 contributors.  Most of the activity was on the tooling side.

  Higher level changes:

   - New 'perf kvm' analysis tool, from Xiao Guangrong.

   - New 'perf trace' system-wide tracing tool

   - uprobes fixes + cleanups from Oleg Nesterov.

   - Lots of patches to make perf build on Android out of box, from
     Irina Tirdea

   - Extend ftrace function tracing utility to be more dynamic for its
     users.  It allows for data passing to the callback functions, as
     well as reading regs as if a breakpoint were to trigger at function
     entry.

     The main goal of this patch series was to allow kprobes to use
     ftrace as an optimized probe point when a probe is placed on an
     ftrace nop.  With lots of help from Masami Hiramatsu, and going
     through lots of iterations, we finally came up with a good
     solution.

   - Add cpumask for uncore pmu, use it in 'stat', from Yan, Zheng.

   - Various tracing updates from Steve Rostedt

   - Clean up and improve 'perf sched' performance by elliminating lots
     of needless calls to libtraceevent.

   - Event group parsing support, from Jiri Olsa

   - UI/gtk refactorings and improvements from Namhyung Kim

   - Add support for non-tracepoint events in perf script python, from
     Feng Tang

   - Add --symbols to 'script', similar to the one in 'report', from
     Feng Tang.

  Infrastructure enhancements and fixes:

   - Convert the trace builtins to use the growing evsel/evlist
     tracepoint infrastructure, removing several open coded constructs
     like switch like series of strcmp to dispatch events, etc.
     Basically what had already been showcased in 'perf sched'.

   - Add evsel constructor for tracepoints, that uses libtraceevent just
     to parse the /format events file, use it in a new 'perf test' to
     make sure the libtraceevent format parsing regressions can be more
     readily caught.

   - Some strange errors were happening in some builds, but not on the
     next, reported by several people, problem was some parser related
     files, generated during the build, didn't had proper make deps, fix
     from Eric Sandeen.

   - Introduce struct and cache information about the environment where
     a perf.data file was captured, from Namhyung Kim.

   - Fix handling of unresolved samples when --symbols is used in
     'report', from Feng Tang.

   - Add union member access support to 'probe', from Hyeoncheol Lee.

   - Fixups to die() removal, from Namhyung Kim.

   - Render fixes for the TUI, from Namhyung Kim.

   - Don't enable annotation in non symbolic view, from Namhyung Kim.

   - Fix pipe mode in 'report', from Namhyung Kim.

   - Move related stats code from stat to util/, will be used by the
     'stat' kvm tool, from Xiao Guangrong.

   - Remove die()/exit() calls from several tools.

   - Resolve vdso callchains, from Jiri Olsa

   - Don't pass const char pointers to basename, so that we can
     unconditionally use libgen.h and thus avoid ifdef BIONIC lines,
     from David Ahern

   - Refactor hist formatting so that it can be reused with the GTK
     browser, From Namhyung Kim

   - Fix build for another rbtree.c change, from Adrian Hunter.

   - Make 'perf diff' command work with evsel hists, from Jiri Olsa.

   - Use the only field_sep var that is set up: symbol_conf.field_sep,
     fix from Jiri Olsa.

   - .gitignore compiled python binaries, from Namhyung Kim.

   - Get rid of die() in more libtraceevent places, from Namhyung Kim.

   - Rename libtraceevent 'private' struct member to 'priv' so that it
     works in C++, from Steven Rostedt

   - Remove lots of exit()/die() calls from tools so that the main perf
     exit routine can take place, from David Ahern

   - Fix x86 build on x86-64, from David Ahern.

   - {int,str,rb}list fixes from Suzuki K Poulose

   - perf.data header fixes from Namhyung Kim

   - Allow user to indicate objdump path, needed in cross environments,
     from Maciek Borzecki

   - Fix hardware cache event name generation, fix from Jiri Olsa

   - Add round trip test for sw, hw and cache event names, catching the
     problem Jiri fixed, after Jiri's patch, the test passes
     successfully.

   - Clean target should do clean for lib/traceevent too, fix from David
     Ahern

   - Check the right variable for allocation failure, fix from Namhyung
     Kim

   - Set up evsel->tp_format regardless of evsel->name being set
     already, fix from Namhyung Kim

   - Oprofile fixes from Robert Richter.

   - Remove perf_event_attr needless version inflation, from Jiri Olsa

   - Introduce libtraceevent strerror like error reporting facility,
     from Namhyung Kim

   - Add pmu mappings to perf.data header and use event names from cmd
     line, from Robert Richter

   - Fix include order for bison/flex-generated C files, from Ben
     Hutchings

   - Build fixes and documentation corrections from David Ahern

   - Assorted cleanups from Robert Richter

   - Let O= makes handle relative paths, from Steven Rostedt

   - perf script python fixes, from Feng Tang.

   - Initial bash completion support, from Frederic Weisbecker

   - Allow building without libelf, from Namhyung Kim.

   - Support DWARF CFI based unwind to have callchains when %bp based
     unwinding is not possible, from Jiri Olsa.

   - Symbol resolution fixes, while fixing support PPC64 files with an
     .opt ELF section was the end goal, several fixes for code that
     handles all architectures and cleanups are included, from Cody
     Schafer.

   - Assorted fixes for Documentation and build in 32 bit, from Robert
     Richter

   - Cache the libtraceevent event_format associated to each evsel
     early, so that we avoid relookups, i.e.  calling pevent_find_event
     repeatedly when processing tracepoint events.

     [ This is to reduce the surface contact with libtraceevents and
        make clear what is that the perf tools needs from that lib: so
        far parsing the common and per event fields.  ]

   - Don't stop the build if the audit libraries are not installed, fix
     from Namhyung Kim.

   - Fix bfd.h/libbfd detection with recent binutils, from Markus
     Trippelsdorf.

   - Improve warning message when libunwind devel packages not present,
     from Jiri Olsa"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (282 commits)
  perf trace: Add aliases for some syscalls
  perf probe: Print an enum type variable in "enum variable-name" format when showing accessible variables
  perf tools: Check libaudit availability for perf-trace builtin
  perf hists: Add missing period_* fields when collapsing a hist entry
  perf trace: New tool
  perf evsel: Export the event_format constructor
  perf evsel: Introduce rawptr() method
  perf tools: Use perf_evsel__newtp in the event parser
  perf evsel: The tracepoint constructor should store sys:name
  perf evlist: Introduce set_filter() method
  perf evlist: Renane set_filters method to apply_filters
  perf test: Add test to check we correctly parse and match syscall open parms
  perf evsel: Handle endianity in intval method
  perf evsel: Know if byte swap is needed
  perf tools: Allow handling a NULL cpu_map as meaning "all cpus"
  perf evsel: Improve tracepoint constructor setup
  tools lib traceevent: Fix error path on pevent_parse_event
  perf test: Fix build failure
  trace: Move trace event enable from fs_initcall to core_initcall
  tracing: Add an option for disabling markers
  ...
2012-10-01 10:28:49 -07:00
Oleg Nesterov ec75fba93e uprobes: Simplify is_swbp_at_addr(), remove stale comments
After the previous change is_swbp_at_addr() is always called with
current->mm. Remove this check and move it close to its single caller.

Also, remove the obsolete comment about is_swbp_at_addr() and
uprobe_state.count.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:54 +02:00
Oleg Nesterov ed6f6a50dc uprobes: Kill set_orig_insn()->is_swbp_at_addr()
Unlike set_swbp(), set_orig_insn()->is_swbp_at_addr() makes sense,
although it can't prevent all confusions.

But the usage of is_swbp_at_addr() is equally confusing, and it adds
the extra get_user_pages() we can avoid.

This patch removes set_orig_insn()->is_swbp_at_addr() but changes
write_opcode() to do the necessary checks before replace_page().

Perhaps it also makes sense to ensure PAGE_MAPPING_ANON in unregister
case.

find_active_uprobe() becomes the only user of is_swbp_at_addr(),
we can change its semantics.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:54 +02:00
Oleg Nesterov cceb55aab7 uprobes: Introduce copy_opcode(), kill read_opcode()
No functional changes, preparations.

1. Extract the kmap-and-memcpy code from read_opcode() into the
   new trivial helper, copy_opcode(). The next patch will add
   another user.

2. read_opcode() becomes really trivial, fold it into its single
   caller, is_swbp_at_addr().

3. Remove "auprobe" argument from write_opcode(), it is not used
   since f403072c6.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:54 +02:00
Oleg Nesterov e97f65a17d uprobes: Kill set_swbp()->is_swbp_at_addr()
A separate patch for better documentation.

set_swbp()->is_swbp_at_addr() is not needed for correctness, it is
harmless to do the unnecessary __replace_page(old_page, new_page)
when these 2 pages are identical.

And it can not be counted as optimization. mmap/register races are
very unlikely, while in the likely case is_swbp_at_addr() adds the
extra get_user_pages() even if the caller is uprobe_mmap(current->mm)
and returns false.

Note also that the semantics/usage of is_swbp_at_addr() in uprobe.c
is confusing. set_swbp() uses it to detect the case when this insn
was already modified by uprobes, that is why it should always compare
the opcode with UPROBE_SWBP_INSN even if the hardware (like powerpc)
has other trap insns. It doesn't matter if this breakpoint was in fact
installed by gdb or application itself, we are going to "steal" this
breakpoint anyway and execute the original insn from vm_file even if
it no longer matches the memory.

OTOH, handle_swbp()->find_active_uprobe() uses is_swbp_at_addr() to
figure out whether we need to send SIGTRAP or not if we can not find
uprobe, so in this case it should return true for all trap variants,
not only for UPROBE_SWBP_INSN.

This patch removes set_swbp()->is_swbp_at_addr(), the next patches
will remove it from set_orig_insn() which is similar to set_swbp()
in this respect. So the only caller will be handle_swbp() and we
can make its semantics clear.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:54 +02:00
Oleg Nesterov e40cfce626 uprobes: Restrict valid_vma(false) to skip VM_SHARED vmas
valid_vma(false) ignores ->vm_flags, this is not actually right.
We should never try to write into MAP_SHARED mapping, this can
confuse an apllication which actually writes to ->vm_file.

With this patch valid_vma(false) ignores VM_WRITE only but checks
other (immutable) bits checked by valid_vma(true). This can also
speedup uprobe_munmap() and uprobe_unregister().

Note: even after this patch _unregister can confuse the probed
application if it does mprotect(PROT_WRITE) after _register and
installs "int3", but this is hardly possible to avoid and this
doesn't differ from gdb case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:54 +02:00
Oleg Nesterov 78a320542e uprobes: Change valid_vma() to demand VM_MAYEXEC rather than VM_EXEC
uprobe_register() or uprobe_mmap() requires VM_READ | VM_EXEC, this
is not right. An apllication can do mprotect(PROT_EXEC) later and
execute this code.

Change valid_vma(is_register => true) to check VM_MAYEXEC instead.
No need to check VM_MAYREAD, it is always set.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:53 +02:00
Oleg Nesterov 75ed82ea53 uprobes: Change write_opcode() to use FOLL_FORCE
write_opcode()->get_user_pages() needs FOLL_FORCE to ensure we can
read the page even if the probed task did mprotect(PROT_NONE) after
uprobe_register(). Without FOLL_WRITE, FOLL_FORCE doesn't have any
side effect but allows to read the !VM_READ memory.

Otherwiese the subsequent uprobe_unregister()->set_orig_insn() fails
and we leak "int3". If that task does mprotect(PROT_READ | EXEC) and
execute the probed insn later it will be killed.

Note: in fact this is also needed for _register, see the next patch.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:53 +02:00
Oleg Nesterov db023ea595 uprobes: Move clear_thread_flag(TIF_UPROBE) to uprobe_notify_resume()
Move clear_thread_flag(TIF_UPROBE) from do_notify_resume() to
uprobe_notify_resume() for !CONFIG_UPROBES case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:53 +02:00
Oleg Nesterov 1b08e90721 uprobes: Kill UTASK_BP_HIT state
Kill UTASK_BP_HIT state, it buys nothing but complicates the code.
It is only used in uprobe_notify_resume() to decide who should be
called, we can check utask->active_uprobe != NULL instead. And this
allows us to simplify handle_swbp(), no need to clear utask->state.

Likewise we could kill UTASK_SSTEP, but UTASK_BP_HIT is worse and
imho should die. The problem is, it creates the special case when
task->utask is NULL, we can't distinguish RUNNING and BP_HIT. With
this patch utask == NULL always means RUNNING.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:53 +02:00
Oleg Nesterov 0578a97098 uprobes: Fix UPROBE_SKIP_SSTEP checks in handle_swbp()
If handle_swbp()->add_utask() fails but UPROBE_SKIP_SSTEP is set,
cleanup_ret: path do not restart the insn, this is wrong. Remove
this check and add the additional label for can_skip_sstep() = T
case.

Note also that UPROBE_SKIP_SSTEP can be false positive, we simply
can not trust it unless arch_uprobe_skip_sstep() was already called.

Also, move another UPROBE_SKIP_SSTEP check before can_skip_sstep()
into this helper, this looks more clean and understandable.

Note: probably we should rename "skip" to "emulate" and I think
that "clear UPROBE_SKIP_SSTEP" should be moved to arch_can_skip.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:52 +02:00
Oleg Nesterov 746a9e6ba2 uprobes: Do not setup ->active_uprobe/state prematurely
handle_swbp() sets utask->active_uprobe before handler_chain(),
and UTASK_SSTEP before pre_ssout(). This complicates the code
for no reason,  arch_ hooks or consumer->handler() should not
(and can't) use this info.

Change handle_swbp() to initialize them after pre_ssout(), and
remove the no longer needed cleanup-utask code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
cked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:52 +02:00
Oleg Nesterov 79d54b249c uprobes: Do not leak UTASK_BP_HIT if find_active_uprobe() fails
If handle_swbp()->find_active_uprobe() fails we return with
utask->state = UTASK_BP_HIT.

Change handle_swbp() to reset utask->state at the start. Note
that we do this unconditionally, see the next patch(es).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-29 21:21:52 +02:00
Al Viro 2903ff019b switch simple cases of fget_light to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:08 -04:00
Al Viro ab72a7028c events: don't use get_unused_fd_flags() when get_unused_fd() will do
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:08:52 -04:00
Sebastian Andrzej Siewior 9d77878226 uprobes: Introduce arch_uprobe_enable/disable_step()
As Oleg pointed out in [0] uprobe should not use the ptrace interface
for enabling/disabling single stepping.

[0] http://lkml.kernel.org/r/20120730141638.GA5306@redhat.com

Add the new "__weak arch" helpers which simply call user_*_single_step()
as a preparation. This is only needed to not break the powerpc port, we
will fold this logic into arch_uprobe_pre/post_xol() hooks later.

We should also change handle_singlestep(), _disable_step(&uprobe->arch)
should be called before put_uprobe().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-15 17:37:28 +02:00
Oleg Nesterov 499a4f3ec0 uprobes: Teach find_active_uprobe() to clear MMF_HAS_UPROBES
The wrong MMF_HAS_UPROBES doesn't really hurt, just it triggers
the "slow" and unnecessary handle_swbp() path if the task hits
the non-uprobe breakpoint.

So this patch changes find_active_uprobe() to check every valid
vma and clear MMF_HAS_UPROBES if no uprobes were found. This is
adds the slow O(n) path, but it is only called in unlikely case
when the task hits the normal breakpoint first time after
uprobe_unregister().

Note the "not strictly accurate" comment in mmf_recalc_uprobes().
We can fix this, we only need to teach vma_has_uprobes() to return
a bit more more info, but I am not sure this worth the trouble.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-15 17:37:27 +02:00
Oleg Nesterov 9f68f672c4 uprobes: Introduce MMF_RECALC_UPROBES
Add the new MMF_RECALC_UPROBES flag, it means that MMF_HAS_UPROBES
can be false positive after remove_breakpoint() or uprobe_munmap().
It is also set by uprobe_dup_mmap(), this is not optimal but simple.
We could add the new hook, uprobe_dup_vma(), to set MMF_HAS_UPROBES
only if the new mm actually has uprobes, but I don't think this
makes sense.

The next patch will use this flag to clear MMF_HAS_UPROBES.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-15 17:37:27 +02:00
Oleg Nesterov 6f47caa0e1 uprobes: uprobes_treelock should not disable irqs
Nobody plays with uprobes_tree/uprobes_treelock in interrupt context,
no need to disable irqs.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-15 17:37:26 +02:00
Sebastian Andrzej Siewior 6d1d8dfa8b uprobes: Don't put NULL pointer in uprobe_register()
alloc_uprobe() might return a NULL pointer, put_uprobe() can't deal with
this.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-09-15 17:34:05 +02:00
Tejun Heo 8c7f6edbda cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them
Currently, cgroup hierarchy support is a mess.  cpu related subsystems
behave correctly - configuration, accounting and control on a parent
properly cover its children.  blkio and freezer completely ignore
hierarchy and treat all cgroups as if they're directly under the root
cgroup.  Others show yet different behaviors.

These differing interpretations of cgroup hierarchy make using cgroup
confusing and it impossible to co-mount controllers into the same
hierarchy and obtain sane behavior.

Eventually, we want full hierarchy support from all subsystems and
probably a unified hierarchy.  Users using separate hierarchies
expecting completely different behaviors depending on the mounted
subsystem is deterimental to making any progress on this front.

This patch adds cgroup_subsys.broken_hierarchy and sets it to %true
for controllers which are lacking in hierarchy support.  The goal of
this patch is two-fold.

* Move users away from using hierarchy on currently non-hierarchical
  subsystems, so that implementing proper hierarchy support on those
  doesn't surprise them.

* Keep track of which controllers are broken how and nudge the
  subsystems to implement proper hierarchy support.

For now, start with a single warning message.  We can whine louder
later on.

v2: Fixed a typo spotted by Michal. Warning message updated.

v3: Updated memcg part so that it doesn't generate warning in the
    cases where .use_hierarchy=false doesn't make the behavior
    different from root.use_hierarchy=true.  Fixed a typo spotted by
    Glauber.

v4: Check ->broken_hierarchy after cgroup creation is complete so that
    ->create() can affect the result per Michal.  Dropped unnecessary
    memcg root handling per Michal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2012-09-14 12:01:16 -07:00
K.Prasad 500ad2d8b0 perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled
While debugging a warning message on PowerPC while using hardware
breakpoints, it was discovered that when perf_event_disable is invoked
through hw_breakpoint_handler function with interrupts disabled, a
subsequent IPI in the code path would trigger a WARN_ON_ONCE message in
smp_call_function_single function.

This patch calls __perf_event_disable() when interrupts are already
disabled, instead of perf_event_disable().

Reported-by: Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com>
Signed-off-by: K.Prasad <Prasad.Krishnan@gmail.com>
[naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task]
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain
[ Fixed build error on MIPS. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-09-04 17:29:53 +02:00
Al Viro a6fa941d94 perf_event: Switch to internal refcount, fix race with close()
Don't mess with file refcounts (or keep a reference to file, for
that matter) in perf_event.  Use explicit refcount of its own
instead.  Deal with the race between the final reference to event
going away and new children getting created for it by use of
atomic_long_inc_not_zero() in inherit_event(); just have the
latter free what it had allocated and return NULL, that works
out just fine (children of siblings of something doomed are
created as singletons, same as if the child of leader had been
created and immediately killed).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120820135925.GG23464@ZenIV.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-09-04 17:29:22 +02:00
Oleg Nesterov ded86e7c8f uprobes: Remove "verify" argument from set_orig_insn()
Nobody does set_orig_insn(verify => false), and I think nobody will.
Remove this argument. IIUC set_orig_insn(verify => false) was needed
to single-step without xol area.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:20 +02:00
Oleg Nesterov 61559a8165 uprobes: Fold uprobe_reset_state() into uprobe_dup_mmap()
Now that we have uprobe_dup_mmap() we can fold uprobe_reset_state()
into the new hook and remove it. mmput()->uprobe_clear_state() can't
be called before dup_mmap().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:19 +02:00
Oleg Nesterov f8ac4ec9c0 uprobes: Introduce MMF_HAS_UPROBES
Add the new MMF_HAS_UPROBES flag. It is set by install_breakpoint()
and it is copied by dup_mmap(), uprobe_pre_sstep_notifier() checks
it to avoid the slow path if the task was never probed. Perhaps it
makes sense to check it in valid_vma(is_register => false) as well.

This needs the new dup_mmap()->uprobe_dup_mmap() hook. We can't use
uprobe_reset_state() or put MMF_HAS_UPROBES into MMF_INIT_MASK, we
need oldmm->mmap_sem to avoid the race with uprobe_register() or
mmap() from another thread.

Currently we never clear this bit, it can be false-positive after
uprobe_unregister() or uprobe_munmap() or if dup_mmap() hits the
probed VM_DONTCOPY vma. But this is fine correctness-wise and has
no effect unless the task hits the non-uprobe breakpoint.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:18 +02:00
Oleg Nesterov 78f7411668 uprobes: Do not use -EEXIST in install_breakpoint() paths
-EEXIST from install_breakpoint() no longer makes sense, all
callers should simply treat it as "success". Change the code
to return zero and simplify register_for_each_vma().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:18 +02:00
Oleg Nesterov 5e5be71ab3 uprobes: Change uprobe_mmap() to ignore the errors but check fatal_signal_pending()
Once install_breakpoint() fails uprobe_mmap() "ignores" all other
uprobes and returns the error.

It was never really needed to to stop after the first error, and
in fact it was always wrong at least in -ENOTSUPP case.

Change uprobe_mmap() to ignore the errors and always return 0.
This is not what we want in the long term, but until we teach
the callers to handle the failure it would be better to remove
the pointless complications. And this doesn't look too bad, the
only "reasonable" error is ENOMEM but in this case the caller
should be oom-killed in the likely case or the system has more
serious problems.

However it makes sense to stop if fatal_signal_pending() == T.
In particular this helps if the task was oom-killed.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:17 +02:00
Oleg Nesterov f1a45d0231 uprobes: Kill dup_mmap()->uprobe_mmap(), simplify uprobe_mmap/munmap
1. Kill dup_mmap()->uprobe_mmap(), it was only needed to calculate
   new_mm->uprobes_state.count removed by the previous patch.

   If the forking process has a pending uprobe (int3) in vma, it will
   be copied by copy_page_range(), note that it checks vma->anon_vma
   so "Don't copy ptes" is not possible after install_breakpoint()
   which does anon_vma_prepare().

2. Remove is_swbp_at_addr() and "int count" in uprobe_mmap(). Again,
   this was needed for uprobes_state.count.

   As a side effect this fixes the bug pointed out by Srikar,
   this code lacked the necessary put_uprobe().

3. uprobe_munmap() becomes a nop after the previous patch. Remove the
   meaningless code but do not remove the helper, we will need it.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:17 +02:00
Oleg Nesterov 647c42dfd4 uprobes: Kill uprobes_state->count
uprobes_state->count is only needed to avoid the slow path in
uprobe_pre_sstep_notifier(). It is also checked in uprobe_munmap()
but ironically its only goal to decrement this counter. However,
it is very broken. Just some examples:

- uprobe_mmap() can race with uprobe_unregister() and wrongly
  increment the counter if it hits the non-uprobe "int3". Note
  that install_breakpoint() checks ->consumers first and returns
  -EEXIST if it is NULL.

  "atomic_sub() if error" in uprobe_mmap() looks obviously wrong
  too.

- uprobe_munmap() can race with uprobe_register() and wrongly
  decrement the counter by the same reason.

- Suppose an appication tries to increase the mmapped area via
  sys_mremap(). vma_adjust() does uprobe_munmap(whole_vma) first,
  this can nullify the counter temporarily and race with another
  thread which can hit the bp, the application will be killed by
  SIGTRAP.

- Suppose an application mmaps 2 consecutive areas in the same file
  and one (or both) of these areas has uprobes. In the likely case
  mmap_region()->vma_merge() suceeds. Like above, this leads to
  uprobe_munmap/uprobe_mmap from vma_merge()->vma_adjust() but then
  mmap_region() does another uprobe_mmap(resulting_vma) and doubles
  the counter.

This patch only removes this counter and fixes the compile errors,
then we will try to cleanup the changed code and add something else
instead.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2012-08-28 18:21:16 +02:00
Sebastian Andrzej Siewior 8bd874456e uprobes: Remove check for uprobe variable in handle_swbp()
by the time we get here (after we pass cleanup_ret) uprobe is always is
set. If it is NULL we leave very early in the code.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2012-08-28 18:21:16 +02:00
Srikar Dronamraju 61e1d39498 uprobes: Remove redundant lock_page/unlock_page
Since read_opcode() reads from the referenced page and doesnt modify
the page contents nor the page attributes, there is no need to lock
the page.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2012-08-28 18:21:15 +02:00
Frederic Weisbecker d077526485 perf: Add attribute to filter out callchains
Introducing following bits to the the perf_event_attr struct:

  - exclude_callchain_kernel to filter out kernel callchain
    from the sample dump

  - exclude_callchain_user to filter out user callchain
    from the sample dump

We need to be able to disable standard user callchain dump when we use
the dwarf cfi callchain mode, because frame pointer based user
callchains are useless in this mode.

Implementing also exclude_callchain_kernel to have complete set of
options.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
[ Added kernel callchains filtering ]
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-7-git-send-email-jolsa@redhat.com
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-10 12:40:57 -03:00
Jiri Olsa c5ebcedb56 perf: Add ability to attach user stack dump to sample
Introducing PERF_SAMPLE_STACK_USER sample type bit to trigger the dump
of the user level stack on sample. The size of the dump is specified by
sample_stack_user value.

Being able to dump parts of the user stack, starting from the stack
pointer, will be useful to make a post mortem dwarf CFI based stack
unwinding.

Added HAVE_PERF_USER_STACK_DUMP config option to determine if the
architecture provides user stack dump on perf event samples.  This needs
access to the user stack pointer which is not unified across
architectures. Enabling this for x86 architecture.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Original-patch-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-6-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-10 12:17:58 -03:00