Commit Graph

100 Commits

Author SHA1 Message Date
Michael Petlan 4a4c03c1bb perf annotate: Support full source file paths for srcline fix
The --full-paths option did not show the full source file paths in the 'perf
annotate' tool, because the value of the option was not propagated into the
related functions.

With this patch the value of the --full-paths option is known to the function
that composes the srcline string, so it prints the full path when necessary.

Committer Note:

This affects annotate when the --print-line option is used:

  # perf annotate -h 2>&1 | grep print-line
      -l, --print-line      print matching source lines (may be slow)

Looking just at the lines that should be affected by this change:

Before:

  # perf annotate --print-line --full-paths --stdio fput | grep '\.[ch]:[0-9]\+'
     94.44 atomic64_64.h:114
      5.56 file_table.c:265
   file_table.c:265    5.56 :	  ffffffff81219a00:       callq  ffffffff81769360 <__fentry__>
   atomic64_64.h:114   94.44 :	  ffffffff81219a05:       lock decq 0x38(%rdi)

After:

  # perf annotate --print-line --full-paths --stdio fput | grep '\.[ch]:[0-9]\+'
     94.44 /home/git/linux/arch/x86/include/asm/atomic64_64.h:114
      5.56 /home/git/linux/fs/file_table.c:265
   /home/git/linux/fs/file_table.c:265    5.56 :	  ffffffff81219a00:       callq  ffffffff81769360 <__fentry__>
   /home/git/linux/arch/x86/include/asm/atomic64_64.h:114   94.44 :	  ffffffff81219a05:       lock decq 0x38(%rdi)
  #

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://permalink.gmane.org/gmane.linux.kernel.perf.user/2365
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-11 18:41:30 -03:00
Andi Kleen 62ec9b3f02 perf annotate: Inform the user about objdump failures in --stdio
When the browser fails to annotate it is difficult for users to find out
what went wrong.

Add some errors for objdump failures that are displayed in the UI.

Note it would be even better to handle these errors smarter, like
falling back to the binary when the debug info is somehow corrupted. But
for now just giving a better error is an improvement.

Committer note:

This works for --stdio, where errors just scroll by the screen:

  # perf annotate --stdio intel_idle
  Failure running objdump  --start-address=0xffffffff81418290 --stop-address=0xffffffff814183ae -l -d --no-show-raw -S -C /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 2>/dev/null|grep -v /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1|expand
   Percent |      Source code & Disassembly of vmlinux for cycles:pp
  ------------------------------------------------------------------

And with that one can use that command line to try to find out more about what
happened instead of getting a blank screen, an improvement.

We need tho to improve this further to get it to work with other UIs, like
--tui and --gtk, where it continues showing a blank screen, no messages, as
the pr_err() used is enough just for --stdio.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1446779167-18949-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-06 10:20:48 -03:00
Arnaldo Carvalho de Melo e3d006ce81 perf annotate: Add debug message for out of bounds sample
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-q0lde9ajs84oi38nlyjcqbwg@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-21 18:12:37 -03:00
Adrian Hunter 133de94043 perf tools: /proc/kcore requires CAP_SYS_RAWIO message too noisy
The "/proc/kcore requires CAP_SYS_RAWIO" message comes up all the time
for 'perf script' if vmlinux is not found and the user isn't root, even
when the kernel is not being traced and even though the message is only
really relevant for annotation.

Change it to pr_debug and instead put a note in the message displayed if
annotation is not possible.

Also, the file being accessed might not be /proc/kcore.  Tools can be
directed to a different location using the --kallsyms option in which
case kcore is expected to be in the same directory.  Adjust the message
so it is not misleading in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1440065260-8802-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-21 10:29:23 -03:00
Adrian Hunter 3d7245b094 perf annotate: Fix 32-bit compilation error in util/annotate.c
Fix the following 32-bit compilation errors:

  util/annotate.c: In function ‘addr_map_symbol__account_cycles’:
  util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘u64’ [-Werror=format=]
    pr_debug2("BB with bad start: addr %lx start %lx sym %lx saddr %lx\n",
      ^
  util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘u64’ [-Werror=format=]
  util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 6 has type ‘u64’ [-Werror=format=]

These were introduced by the patch:

"perf report: Add infrastructure for a cycles histogram"

Also change the 'saddr' variable from 'unsigned long' to 'u64'
noting that theoretically we could be processing data captured
on a 64-bit machine but processing it on a 32-bit machine.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: d4957633bf ("perf report: Add infrastructure for a cycles histogram")
Link: http://lkml.kernel.org/r/1439536294-18241-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-17 11:06:21 -03:00
Andi Kleen d4957633bf perf report: Add infrastructure for a cycles histogram
This adds the basic infrastructure to keep track of cycle counts per
basic block for annotate. We allocate an array similar to the normal
accounting, and then account branch cycles there.

We handle two cases:

cycles per basic block with start and cycles per branch (these are later
used for either IPC or just cycles per BB)

In the start case we cannot handle overlaps, so always the longest basic
block wins.

For the cycles per branch case everything is accurately accounted.

v2: Remove unnecessary checks. Slight restructure. Move
symbol__get_annotation to another patch. Move histogram allocation.
v3: Merged with current tree

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1437233094-12844-4-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-06 16:32:45 -03:00
Arnaldo Carvalho de Melo 276af92f10 perf annotate: Rename source_line_percent to source_line_samples
To better reflect the purpose of this struct, that is to hold
info about samples, its total number and is percentage.

Cc: Martin Liska <mliska@suse.cz>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-6bf8gwcl975uurl0ttpvtk69@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-06-19 16:39:21 -03:00
Martin Liška 0c4a5bcea4 perf annotate: Display total number of samples with --show-total-period
To compare two records on an instruction base, with --show-total-period
option provided, display total number of samples that belong to a line
in assembly language.

New hot key 't' is introduced for 'perf annotate' TUI.

Signed-off-by: Martin Liska <mliska@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/5583E26D.1040407@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-06-19 16:39:18 -03:00
Andi Kleen 83be34a7a9 perf annotation: Add symbol__get_annotation
Add a new utility function to get an function annotation out of existing
code.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1432749114-904-4-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-27 20:30:56 -03:00
Ingo Molnar 072e5a1cfa Merge branch 'perf/urgent' into perf/core, to pick up fixes and to refresh the tree
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 09:46:03 +01:00
Jiri Olsa 2c7da8c590 perf annotate: Allow annotation for decompressed kernel modules
Decompressing kernel module file for objdump command if needed.
Annotation commands now display annotation for compressed kernel
modules.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-x4jcytk2d5qjmnjvb0w75q3f@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-23 12:49:27 -03:00
Arnaldo Carvalho de Melo 3995614d9b perf annotate: Fix fallback to unparsed disassembler line
When annotating source/disasm lines the perf tools parse the output of
objdump, trying to provide augmented output that allows navigating
jumps, calls, etc.

But when a line output by objdump can't be parsed the annotation code
falls back to just presenting the unparsed line.

When fixing a leak in the 0fb9f2aab7 commit ("perf annotate: Fix
memory leaks in LOCK handling") we failed to take that into account and
instead tried to free one of the data structures that should be freed
only when successfully allocated, oops, segfault.

There was a change in the way the objdump output for lock prefixed
instructions is formatted that lead the relevant parser to fail to grok
it.

At least RHEL7 works ok, but Fedora 20 segfaults.

Fix it by making the ins__delete() destructor work like the most basic
destructor: free().

Namely make it accept a NULL pointer and when handling it just do
nothing.

Further investigation is needed to figure out the nature of the objdump
output change so as to make the parser grok it.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabin@rab.in>
Link: http://lkml.kernel.org/n/tip-7wsy0zo292pif0yjoqpfryrz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-05 15:27:28 -03:00
Arnaldo Carvalho de Melo 48000a1aed perf tools: Remove EOL whitespaces
Janitorial stuff: boredom moment.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-u70i7shys3kths4hzru72bha@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-01-21 13:24:31 -03:00
Rabin Vincent 0fb9f2aab7 perf annotate: Fix memory leaks in LOCK handling
The lock prefix handling fails to free the strdup()'d name as well as
the fields allocated by the instruction parsing.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/1421607621-15005-2-git-send-email-rabin@rab.in
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-01-21 10:05:32 -03:00
Rabin Vincent be81908c22 perf annotate: Handle ins parsing failures
Don't use the ins's ->sncprintf() if the parsing failed.

For example, this fixes the display of "imul %edx".  Without this patch:

       |      imul   (null),(null)

After this patch:

       |      imul   %edx

Signed-off-by: Rabin Vincent <rabin@rab.in>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421607621-15005-1-git-send-email-rabin@rab.in
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-01-21 10:05:17 -03:00
Andi Kleen 85c116a6cb perf callchain: Make get_srcline fall back to sym+offset
When the source line is not found fall back to sym + offset.  This is
generally much more useful than a raw address.

For this we need to pass in the symbol from the caller.

For some callers it's awkward to compute, so we stay at the old
behaviour.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-10-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-11-24 18:03:47 -03:00
Andi Kleen e592488c01 perf annotate: Support source line numbers in annotate
With srcline key/sort'ing it's useful to have line numbers in the
annotate window. This patch implements this.

Use objdump -l to request the line numbers and save them in the line
structure. Then the browser displays them for source lines.

The line numbers are not displayed by default, but can be toggled on
with 'k'

There is one unfortunate problem with this setup. For lines not
containing source and which are outside functions objdump -l reports
line numbers off by a few: it always reports the first line number in
the next function even for lines that are outside the function.

I haven't found a nice way to detect/correct this. Probably objdump has
to be fixed.

See https://sourceware.org/bugzilla/show_bug.cgi?id=16433

The line numbers are still useful even with these problems, as most are
correct and the ones which are not are nearby.

v2: Fix help text. Handle (discriminator...) output in objdump.
Left align the line numbers.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-9-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-11-19 12:33:48 -03:00
Adrian Hunter ee205503f2 perf tools: Fix annotation with kcore
Patch "perf tools: Fix build-id matching on vmlinux" breaks annotation
with kcore.  The problem is that symbol__annotate() first gets the
filename based on the build-id which was previously not set.

This patch provides a quick fix, however there should probably be only
one way to determine the filename. e.g.  symbol__annotate() should use
the same way as dso__data_fd().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1415700294-30816-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-11-19 12:33:47 -03:00
Arnaldo Carvalho de Melo 2c241bd35e perf symbols: Make sym->end be the first address after the symbol range
To follow vm_area_struct->vm_end convention.

By adhering to the convention that ->end is the first address outside
the symbol's range we can do things like:

	sym->end = start + len;
	len = sym->end - sym->start;

This is also now the convention used for struct map->end, fixing some
off-by-one bugs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-agomujr7tuqaq6lu7kr6z7h6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-10-14 17:50:58 -03:00
Alex Converse 1e2bb043f1 perf annotate: Don't truncate Intel style addresses
Instructions like "mov r9,QWORD PTR [rdx+0x8]" were being truncated to
"mov r9,QWORD" by code that assuemd operands cannot have spaces.

Signed-off-by: Alex Converse <aconverse@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1408050180-14088-1-git-send-email-aconverse@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-08-15 10:39:26 -03:00
Arnaldo Carvalho de Melo 972f393bc8 perf symbols: Make sure --symfs usage includes the path separator
Minchan reported that perf failed to load vmlinux if --symfs argument
doesn't end with '/' character.

Fix it by making sure that the '/' path separator is used when composing
pathnames with a --symfs provided directory name.

Reported-by: Minchan Kim <minchan@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-8n4s6b6zvsez5ktanw006125@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-31 09:58:21 -03:00
Arnaldo Carvalho de Melo 9cdbadceca perf annotate: Print the evsel name in the stdio output
So that when showing multiple events annotations, we can figure out
which is which:

  # perf record -a -e instructions,cycles sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.826 MB perf.data (~36078 samples) ]
  # perf evlist
  instructions
  cycles
  # perf annotate intel_idle 2> /dev/null | head -1
   Percent |	Source code & Disassembly of vmlinux for instructions
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-n1r51l329434js84qtb2c6l9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-03-18 18:17:03 -03:00
Namhyung Kim 48c65bda95 perf annotate: Check availability of annotate when processing samples
The TUI of perf report and top support annotation, but stdio and GTK
don't.  So it should be checked before calling hist_entry__inc_addr_
samples() to avoid wasting resources that will never be used.

perf annotate need it regardless of UI and sort keys, so the check
of whether to allocate resources should be on the tools that have
annotate as an option in the TUI, 'report' and 'top', not on the
function called by all of them.

It caused perf annotate on ppc64 to produce zero output, since the
buckets were not being allocated.

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1392859976-32760-1-git-send-email-namhyung@kernel.org
[ Renamed (report,top)__needs_annotate() to ui__has_annotation() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-02-24 11:12:55 -03:00
Arnaldo Carvalho de Melo 74cf249d5c perf tools: Use zfree to help detect use after free bugs
Several areas already used this technique, so do some audit to
consistently use it elsewhere.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-9sbere0kkplwe45ak6rk4a1f@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-12-27 17:08:19 -03:00
Arnaldo Carvalho de Melo 046625231a perf tools: Introduce zfree
For the frequent idiom of:

   free(ptr);
   ptr = NULL;

Make it expect a pointer to the pointer being freed, so that it becomes
clear at first sight that the variable being freed is being modified.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-pfw02ezuab37kha18wlut7ir@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-12-27 15:17:00 -03:00