<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/tools/perf, branch v4.14</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v4.14</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v4.14'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2017-11-09T13:17:32Z</updated>
<entry>
<title>perf trace: Call machine__exit() at exit</title>
<updated>2017-11-09T13:17:32Z</updated>
<author>
<name>Andrei Vagin</name>
<email>avagin@openvz.org</email>
</author>
<published>2017-11-08T00:22:45Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=33974a414ce2324554f75dbd204ff0868f499e32'/>
<id>urn:sha1:33974a414ce2324554f75dbd204ff0868f499e32</id>
<content type='text'>
Otherwise 'perf trace' leaves a temporary file /tmp/perf-vdso.so-XXXXXX.

  $ perf trace -o log true
  $ ls -l /tmp/perf-vdso.*
  -rw------- 1 root root 8192 Nov  8 03:08 /tmp/perf-vdso.so-5bCpD0

Signed-off-by: Andrei Vagin &lt;avagin@openvz.org&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Vasily Averin &lt;vvs@virtuozzo.com&gt;
Link: http://lkml.kernel.org/r/20171108002246.8924-1-avagin@openvz.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Fix eBPF event specification parsing</title>
<updated>2017-11-09T13:10:58Z</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@redhat.com</email>
</author>
<published>2017-11-09T09:02:10Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=a271bfaf30ce8f7f57c6b65c47bff6d306d0b758'/>
<id>urn:sha1:a271bfaf30ce8f7f57c6b65c47bff6d306d0b758</id>
<content type='text'>
Looks like I've reached the new level of stupidity, adding missing braces.

Committer testing:

Given the following eBPF C filter, that will add a record when it
returns true, i.e. when the tv_nsec variable is &gt; 2000ns, should be
built and installed via sys_bpf(), but fails to do so before this patch:

  # cat filter.c
  #include &lt;uapi/linux/bpf.h&gt;
  #define SEC(NAME) __attribute__((section(NAME), used))

  SEC("func=hrtimer_nanosleep rqtp-&gt;tv_nsec")
  int func(void *ctx, int err, long nsec)
  {
	  return nsec &gt; 1000;
  }
  char _license[] SEC("license") = "GPL";
  int _version SEC("version") = LINUX_VERSION_CODE;
  #

  # perf trace -e nanosleep,filter.c usleep 1
  invalid or unsupported event: 'filter.c'
  Run 'perf list' for a list of valid events

   Usage: perf trace [&lt;options&gt;] [&lt;command&gt;]
      or: perf trace [&lt;options&gt;] -- &lt;command&gt; [&lt;options&gt;]
      or: perf trace record [&lt;options&gt;] [&lt;command&gt;]
      or: perf trace record [&lt;options&gt;] -- &lt;command&gt; [&lt;options&gt;]

      -e, --event &lt;event&gt;   event/syscall selector. use 'perf list' to list available events
  #

And works again after it is applied, the nothing is inserted when the co

  # perf trace -e *sleep,filter.c usleep 1
     0.000 ( 0.066 ms): usleep/23994 nanosleep(rqtp: 0x7ffead94a0d0) = 0
  # perf trace -e *sleep,filter.c usleep 2
     0.000 ( 0.008 ms): usleep/24378 nanosleep(rqtp: 0x7fffa021ba50) ...
     0.008 (         ): perf_bpf_probe:func:(ffffffffb410cb30) tv_nsec=2000)
     0.000 ( 0.066 ms): usleep/24378  ... [continued]: nanosleep()) = 0
  #

The intent of 9445464bb831 is kept:

  # perf stat -e 'cpu/uops_executed.core,krava/'  true
  event syntax error: '..cuted.core,krava/'
                                    \___ unknown term

  valid terms: cmask,pc,event,edge,in_tx,any,ldlat,inv,umask,in_tx_cp,offcore_rsp,config,config1,config2,name,period
  Run 'perf list' for a list of valid events

   Usage: perf stat [&lt;options&gt;] [&lt;command&gt;]

      -e, --event &lt;event&gt;   event selector. use 'perf list' to list available events
  #
  # perf stat -e 'cpu/uops_executed.core,period=1/'  true

   Performance counter stats for 'true':

           808,332      cpu/uops_executed.core,period=1/

       0.002997237 seconds time elapsed

  #

Reported-by: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Fixes: 9445464bb831 ("perf tools: Unwind properly location after REJECT")
Link: http://lkml.kernel.org/n/tip-diea0ihbwpxfw6938huv3whj@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Add "reject" option for parse-events.l</title>
<updated>2017-11-09T13:09:03Z</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@redhat.com</email>
</author>
<published>2017-11-08T15:43:09Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=b6af53b7d6fa40262c16753fe2781a3e792d5e1b'/>
<id>urn:sha1:b6af53b7d6fa40262c16753fe2781a3e792d5e1b</id>
<content type='text'>
Arnaldo reported broken builds in some distros using a newer flex
release, 2.6.4, found in Alpine Linux 3.6 and Edge, with flex not
spotting the REJECT macro:

  CC       /tmp/build/perf/util/parse-events-flex.o
  util/parse-events.l: In function 'parse_events_lex':
  /tmp/build/perf/util/parse-events-flex.c:4734:16: error: \
  'reject_used_but_not_detected' undeclared (first use in this function)

It's happening because we put the REJECT under another USER_REJECT macro
in following commit:

  9445464bb831 perf tools: Unwind properly location after REJECT

Fortunately flex provides option for force it to use REJECT, adding it
to parse-events.l.

Reported-by: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Reported-by: Markus Trippelsdorf &lt;markus@trippelsdorf.de&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Reviewed-by: Andi Kleen &lt;andi@firstfloor.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Fixes: 9445464bb831 ("perf tools: Unwind properly location after REJECT")
Link: http://lkml.kernel.org/n/tip-7kdont984mw12ijk7rji6b8p@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'linus' into perf/urgent, to pick up dependent commits</title>
<updated>2017-11-03T11:30:12Z</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2017-11-03T11:30:12Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=294cbd05e32990c3b1a62be27441fc719edebbab'/>
<id>urn:sha1:294cbd05e32990c3b1a62be27441fc719edebbab</id>
<content type='text'>
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
</entry>
<entry>
<title>License cleanup: add SPDX GPL-2.0 license identifier to files with no license</title>
<updated>2017-11-02T10:10:55Z</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-11-01T14:07:57Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=b24413180f5600bcb3bb70fbed5cf186b60864bd'/>
<id>urn:sha1:b24413180f5600bcb3bb70fbed5cf186b60864bd</id>
<content type='text'>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode &amp; Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained &gt;5
   lines of source
 - File already had some variant of a license header in it (even if &lt;5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Philippe Ombredanne &lt;pombredanne@nexb.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>perf tools: Unwind properly location after REJECT</title>
<updated>2017-10-27T14:42:51Z</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2017-10-12T15:03:38Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=9445464bb8318e42e5232b37fc7218ed028517f6'/>
<id>urn:sha1:9445464bb8318e42e5232b37fc7218ed028517f6</id>
<content type='text'>
We have defined YY_USER_ACTION to keep trace of the column location
during events parsing, but we need to clean it up when we call REJECT.

When REJECT is called, the lexer shrinks the text and re-runs the
matching, so we need to address it in resuming the previous location
value to keep it correct for error display, like:

Before:
  $ perf stat -e 'cpu/uops_executed.core,krava/'  true
  event syntax error: '..38;5;9:mi=01;05;37;41:su=48;5;196;38;5;15:sg=48;5;1\
1;38;5;16:ca=48;5;196;38;5;226:tw=48;5;10;38;5;16:ow=48;5;10;38;5;21:st=48;5;\
21;38;50
�'
                                  \___ unknown term

After:
  $ ./perf stat -e 'cpu/uops_executed.core,krava/'  true
  event syntax error: '..cuted.core,krava/'
                                    \___ unknown term

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Reported-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Changbin Du &lt;changbin.du@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/n/tip-vug2hchlny30jfsfrumbym26@git.kernel.org
Link: http://lkml.kernel.org/r/20171009140944.GD28623@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf symbols: Fix memory corruption because of zero length symbols</title>
<updated>2017-10-25T16:01:09Z</updated>
<author>
<name>Ravi Bangoria</name>
<email>ravi.bangoria@linux.vnet.ibm.com</email>
</author>
<published>2017-10-24T14:20:06Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=331c7cb307971eac38e9470340e10c87855bf4bc'/>
<id>urn:sha1:331c7cb307971eac38e9470340e10c87855bf4bc</id>
<content type='text'>
Perf top is often crashing at very random locations on powerpc.  After
investigating, I found the crash only happens when sample is of zero
length symbol. Powerpc kernel has many such symbols which does not
contain length details in vmlinux binary and thus start and end
addresses of such symbols are same.

Structure

  struct sym_hist {
        u64                   nr_samples;
        u64                   period;
        struct sym_hist_entry addr[0];
  };

has last member 'addr[]' of size zero. 'addr[]' is an array of addresses
that belongs to one symbol (function). If function consist of 100
instructions, 'addr' points to an array of 100 'struct sym_hist_entry'
elements. For zero length symbol, it points to the *empty* array, i.e.
no members in the array and thus offset 0 is also invalid for such
array.

  static int __symbol__inc_addr_samples(...)
  {
        ...
        offset = addr - sym-&gt;start;
        h = annotation__histogram(notes, evidx);
        h-&gt;nr_samples++;
        h-&gt;addr[offset].nr_samples++;
        h-&gt;period += sample-&gt;period;
        h-&gt;addr[offset].period += sample-&gt;period;
        ...
  }

Here, when 'addr' is same as 'sym-&gt;start', 'offset' becomes 0, which is
valid for normal symbols but *invalid* for zero length symbols and thus
updating h-&gt;addr[offset] causes memory corruption.

Fix this by adding one dummy element for zero length symbols.

Link: https://lkml.org/lkml/2016/10/10/148
Fixes: edee44be5919 ("perf annotate: Don't throw error for zero length symbols")
Signed-off-by: Ravi Bangoria &lt;ravi.bangoria@linux.vnet.ibm.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: Naveen N. Rao &lt;naveen.n.rao@linux.vnet.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Taeung Song &lt;treeze.taeung@gmail.com&gt;
Link: http://lkml.kernel.org/r/1508854806-10542-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test shell trace+probe_libc_inet_pton.sh: Be compatible with Debian/Ubuntu</title>
<updated>2017-10-18T12:14:18Z</updated>
<author>
<name>Li Zhijian</name>
<email>lizhijian@cn.fujitsu.com</email>
</author>
<published>2017-10-18T08:34:09Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=74f8e22c153f4464060a0c2e4cfd1d6e51af2109'/>
<id>urn:sha1:74f8e22c153f4464060a0c2e4cfd1d6e51af2109</id>
<content type='text'>
In debian/ubuntu, libc.so is located at a different place,
/lib/x86_64-linux-gnu/libc-2.23.so, so it outputs like this when testing:

  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.040 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.040/0.040/0.040/0.000 ms
  0.000 probe_libc:inet_pton:(7f0e2db741c0))
  __GI___inet_pton (/lib/x86_64-linux-gnu/libc-2.23.so)
  getaddrinfo (/lib/x86_64-linux-gnu/libc-2.23.so)
  [0xffffa9d40f34ff4d] (/bin/ping)

Fix up the libc path to make sure this test works in more OSes.

Committer testing:

When this test fails one can use 'perf test -v', i.e. in verbose mode, where
it'll show the expected backtrace, so, after applying this test:

On Fedora 26:

  # perf test -v ping
  62: probe libc's inet_pton &amp; backtrace it with ping       :
  --- start ---
  test child forked, pid 23322
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.058 ms
  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.058/0.058/0.058/0.000 ms
  0.000 probe_libc:inet_pton:(7fe344310d80))
  __GI___inet_pton (/usr/lib64/libc-2.25.so)
  getaddrinfo (/usr/lib64/libc-2.25.so)
  _init (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  #

Signed-off-by: Li Zhijian &lt;lizhijian@cn.fujitsu.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: Li Zhijian &lt;lizhijian@cn.fujitsu.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Philip Li &lt;philip.li@intel.com&gt;
Link: http://lkml.kernel.org/r/1508315649-18836-1-git-send-email-lizhijian@cn.fujitsu.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf xyarray: Fix wrong processing when closing evsel fd</title>
<updated>2017-10-18T12:09:36Z</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2017-10-18T15:11:18Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=3d8bba9535ac6e79453c769dd0c8ea852a51ad60'/>
<id>urn:sha1:3d8bba9535ac6e79453c769dd0c8ea852a51ad60</id>
<content type='text'>
In current xyarray code, xyarray__max_x() returns max_y, and xyarray__max_y()
returns max_x.

It's confusing and for code logic it looks not correct.

Error happens when closing evsel fd. Let's see this scenario:

1. Allocate an fd (pseudo-code)

  perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
  {
	evsel-&gt;fd = xyarray__new(ncpus, nthreads, sizeof(int));
  }

  xyarray__new(int xlen, int ylen, size_t entry_size)
  {
	size_t row_size = ylen * entry_size;
	struct xyarray *xy = zalloc(sizeof(*xy) + xlen * row_size);

	xy-&gt;entry_size = entry_size;
	xy-&gt;row_size   = row_size;
	xy-&gt;entries    = xlen * ylen;
	xy-&gt;max_x      = xlen;
	xy-&gt;max_y      = ylen;
	......
  }

So max_x is ncpus, max_y is nthreads and row_size = nthreads * 4.

2. Use perf syscall and get the fd

  int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
		     struct thread_map *threads)
  {
	for (cpu = 0; cpu &lt; cpus-&gt;nr; cpu++) {

		for (thread = 0; thread &lt; nthreads; thread++) {
			int fd, group_fd;

			fd = sys_perf_event_open(&amp;evsel-&gt;attr, pid, cpus-&gt;map[cpu],
						 group_fd, flags);

			FD(evsel, cpu, thread) = fd;
	}
  }

  static inline void *xyarray__entry(struct xyarray *xy, int x, int y)
  {
	return &amp;xy-&gt;contents[x * xy-&gt;row_size + y * xy-&gt;entry_size];
  }

These codes don't have issues. The issue happens in the closing of fd.

3. Close fd.

  void perf_evsel__close_fd(struct perf_evsel *evsel)
  {
	int cpu, thread;

	for (cpu = 0; cpu &lt; xyarray__max_x(evsel-&gt;fd); cpu++)
		for (thread = 0; thread &lt; xyarray__max_y(evsel-&gt;fd); ++thread) {
			close(FD(evsel, cpu, thread));
			FD(evsel, cpu, thread) = -1;
		}
  }

  Since xyarray__max_x() returns max_y (nthreads) and xyarry__max_y()
  returns max_x (ncpus), so above code is actually to be:

        for (cpu = 0; cpu &lt; nthreads; cpu++)
                for (thread = 0; thread &lt; ncpus; ++thread) {
                        close(FD(evsel, cpu, thread));
                        FD(evsel, cpu, thread) = -1;
                }

  It's not correct!

This change is introduced by "475fb533fb7d" ("perf evsel: Fix buffer overflow
while freeing events")

This fix is to let xyarray__max_x() return max_x (ncpus) and
let xyarry__max_y() return max_y (nthreads)

Committer note:

This was also fixed by Ravi Bangoria, who provided the same patch,
noticing the problem with 'perf record':

&lt;quote Ravi&gt;
I see 'perf record -p &lt;pid&gt;' crashes with following log:

   *** Error in `./perf': free(): invalid next size (normal): 0x000000000298b340 ***
   ======= Backtrace: =========
   /lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f7fd85c87e5]
   /lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7f7fd85d137a]
   /lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f7fd85d553c]
   ./perf(perf_evsel__close+0xb4)[0x4b7614]
   ./perf(perf_evlist__delete+0x100)[0x4ab180]
   ./perf(cmd_record+0x1d9)[0x43a5a9]
   ./perf[0x49aa2f]
   ./perf(main+0x631)[0x427841]
   /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f7fd8571830]
   ./perf(_start+0x29)[0x427a59]
&lt;/&gt;

Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@linux.vnet.ibm.com&gt;
Fixes: d74be4767367 ("perf xyarray: Save max_x, max_y")
Link: http://lkml.kernel.org/r/1508339478-26674-1-git-send-email-yao.jin@linux.intel.com
Link: http://lkml.kernel.org/r/1508327446-15302-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf buildid-list: Fix crash when processing PERF_RECORD_NAMESPACE</title>
<updated>2017-10-17T14:09:19Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2017-10-17T13:29:00Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=7f0cd23615040b9e53bb4980c986b721cba08bbc'/>
<id>urn:sha1:7f0cd23615040b9e53bb4980c986b721cba08bbc</id>
<content type='text'>
Thomas reported that 'perf buildid-list' gets a SEGFAULT due to NULL
pointer deref when he ran it on a data with namespace events.  It was
because the buildid_id__mark_dso_hit_ops lacks the namespace event
handler and perf_too__fill_default() didn't set it.

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000000000 in ?? ()
  Missing separate debuginfos, use: dnf debuginfo-install audit-libs-2.7.7-1.fc25.s390x bzip2-libs-1.0.6-21.fc25.s390x elfutils-libelf-0.169-1.fc25.s390x
  +elfutils-libs-0.169-1.fc25.s390x libcap-ng-0.7.8-1.fc25.s390x numactl-libs-2.0.11-2.ibm.fc25.s390x openssl-libs-1.1.0e-1.1.ibm.fc25.s390x perl-libs-5.24.1-386.fc25.s390x
  +python-libs-2.7.13-2.fc25.s390x slang-2.3.0-7.fc25.s390x xz-libs-5.2.3-2.fc25.s390x zlib-1.2.8-10.fc25.s390x
  (gdb) where
  #0  0x0000000000000000 in ?? ()
  #1  0x00000000010fad6a in machines__deliver_event (machines=&lt;optimized out&gt;, machines@entry=0x2c6fd18,
      evlist=&lt;optimized out&gt;, event=event@entry=0x3fffdf00470, sample=0x3ffffffe880, sample@entry=0x3ffffffe888,
      tool=tool@entry=0x1312968 &lt;build_id.mark_dso_hit_ops&gt;, file_offset=1136) at util/session.c:1287
  #2  0x00000000010fbf4e in perf_session__deliver_event (file_offset=1136, tool=0x1312968 &lt;build_id.mark_dso_hit_ops&gt;,
      sample=0x3ffffffe888, event=0x3fffdf00470, session=0x2c6fc30) at util/session.c:1340
  #3  perf_session__process_event (session=0x2c6fc30, session@entry=0x0, event=event@entry=0x3fffdf00470,
      file_offset=file_offset@entry=1136) at util/session.c:1522
  #4  0x00000000010fddde in __perf_session__process_events (file_size=11880, data_size=&lt;optimized out&gt;,
      data_offset=&lt;optimized out&gt;, session=0x0) at util/session.c:1899
  #5  perf_session__process_events (session=0x0, session@entry=0x2c6fc30) at util/session.c:1953
  #6  0x000000000103b2ac in perf_session__list_build_ids (with_hits=&lt;optimized out&gt;, force=&lt;optimized out&gt;)
      at builtin-buildid-list.c:83
  #7  cmd_buildid_list (argc=&lt;optimized out&gt;, argv=&lt;optimized out&gt;) at builtin-buildid-list.c:115
  #8  0x00000000010a026c in run_builtin (p=0x1311f78 &lt;commands+24&gt;, argc=argc@entry=2, argv=argv@entry=0x3fffffff3c0)
      at perf.c:296
  #9  0x000000000102bc00 in handle_internal_command (argv=&lt;optimized out&gt;, argc=2) at perf.c:348
  #10 run_argv (argcp=&lt;synthetic pointer&gt;, argv=&lt;synthetic pointer&gt;) at perf.c:392
  #11 main (argc=&lt;optimized out&gt;, argv=0x3fffffff3c0) at perf.c:536
  (gdb)

Fix it by adding a stub event handler for namespace event.

Committer testing:

Further clarifying, plain using 'perf buildid-list' will not end up in a
SEGFAULT when processing a perf.data file with namespace info:

  # perf record -a --namespaces sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 2.024 MB perf.data (1058 samples) ]
  # perf buildid-list | wc -l
  38
  # perf buildid-list | head -5
  e2a171c7b905826fc8494f0711ba76ab6abbd604 /lib/modules/4.14.0-rc3+/build/vmlinux
  874840a02d8f8a31cedd605d0b8653145472ced3 /lib/modules/4.14.0-rc3+/kernel/arch/x86/kvm/kvm-intel.ko
  ea7223776730cd8a22f320040aae4d54312984bc /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/i915/i915.ko
  5961535e6732a8edb7f22b3f148bb2fa2e0be4b9 /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/drm.ko
  f045f54aa78cf1931cc893f78b6cbc52c72a8cb1 /usr/lib64/libc-2.25.so
  #

It is only when one asks for checking what of those entries actually had
samples, i.e. when we use either -H or --with-hits, that we will process
all the PERF_RECORD_ events, and since tools/perf/builtin-buildid-list.c
neither explicitely set a perf_tool.namespaces() callback nor the
default stub was set that we end up, when processing a
PERF_RECORD_NAMESPACE record, causing a SEGFAULT:

  # perf buildid-list -H
  Segmentation fault (core dumped)
  ^C
  #

Reported-and-Tested-by: Thomas-Mich Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Hari Bathini &lt;hbathini@linux.vnet.ibm.com&gt;
Cc: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas-Mich Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Fixes: f3b3614a284d ("perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info")
Link: http://lkml.kernel.org/r/20171017132900.11043-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
</feed>
