<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools/perf, branch v6.2-rc3</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>perf tools: Fix build on uClibc systems by adding missing sys/types.h include</title>
<updated>2023-01-04T19:44:01+00:00</updated>
<author>
<name>Jesus Sanchez-Palencia</name>
<email>jesussanp@google.com</email>
</author>
<published>2023-01-04T19:34:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=481028dbf1daa2808e1be06f6a865b5fe5939efc'/>
<id>481028dbf1daa2808e1be06f6a865b5fe5939efc</id>
<content type='text'>
Not all libc implementations define ssize_t as part of stdio.h like
glibc does since the standard only requires this type to be defined by
unistd.h and sys/types.h. For this reason the perf build is currently
broken for toolchains based on uClibc, for instance.

Include sys/types.h explicitly to fix that.

Committer notes:

In addition, in the past this worked in uClibc test systems as there was
another way to get to sys/types.h that got removed in that cset:

  tools/perf/util/trace-event.h
    /usr/include/traceevent/event_parse.h # This got removed from util/trace-event.h in 378ef0f5d9d7f465
      /usr/include/regex.h
        /usr/include/sys/types.h
          typedef __ssize_t ssize_t;

So the size_t that is used in tools/perf/util/trace-event.h was being
obtained indirectly, by chance.

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Signed-off-by: Jesus Sanchez-Palencia &lt;jesussanp@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20230104193414.606905-1-jesussanp@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Not all libc implementations define ssize_t as part of stdio.h like
glibc does since the standard only requires this type to be defined by
unistd.h and sys/types.h. For this reason the perf build is currently
broken for toolchains based on uClibc, for instance.

Include sys/types.h explicitly to fix that.

Committer notes:

In addition, in the past this worked in uClibc test systems as there was
another way to get to sys/types.h that got removed in that cset:

  tools/perf/util/trace-event.h
    /usr/include/traceevent/event_parse.h # This got removed from util/trace-event.h in 378ef0f5d9d7f465
      /usr/include/regex.h
        /usr/include/sys/types.h
          typedef __ssize_t ssize_t;

So the size_t that is used in tools/perf/util/trace-event.h was being
obtained indirectly, by chance.

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Signed-off-by: Jesus Sanchez-Palencia &lt;jesussanp@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20230104193414.606905-1-jesussanp@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf stat: Fix handling of --for-each-cgroup with --bpf-counters to match non BPF mode</title>
<updated>2023-01-04T14:11:41+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-01-04T06:44:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=54b353a20c7e8be98414754f5aff98c8a68fcc1f'/>
<id>54b353a20c7e8be98414754f5aff98c8a68fcc1f</id>
<content type='text'>
The --for-each-cgroup can have the same cgroup multiple times, but this
confuses BPF counters (since they have the same cgroup id), making only
the last cgroup events to be counted.

Let's check the cgroup name before adding a new entry to the cgroups
list.

Before:

  $ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1

   Performance counter stats for 'system wide':

       &lt;not counted&gt; msec cpu-clock                        /
       &lt;not counted&gt;      context-switches                 /
       &lt;not counted&gt;      cpu-migrations                   /
       &lt;not counted&gt;      page-faults                      /
       &lt;not counted&gt;      cycles                           /
       &lt;not counted&gt;      instructions                     /
       &lt;not counted&gt;      branches                         /
       &lt;not counted&gt;      branch-misses                    /
            8,016.04 msec cpu-clock                        /                #    7.998 CPUs utilized
               6,152      context-switches                 /                #  767.461 /sec
                 250      cpu-migrations                   /                #   31.187 /sec
                 442      page-faults                      /                #   55.139 /sec
         613,111,487      cycles                           /                #    0.076 GHz
         280,599,604      instructions                     /                #    0.46  insn per cycle
          57,692,724      branches                         /                #    7.197 M/sec
           3,385,168      branch-misses                    /                #    5.87% of all branches

         1.002220125 seconds time elapsed

After it becomes similar to the non-BPF mode:

  $ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/  sleep 1

   Performance counter stats for 'system wide':

            8,013.38 msec cpu-clock                        /                #    7.998 CPUs utilized
               6,859      context-switches                 /                #  855.944 /sec
                 334      cpu-migrations                   /                #   41.680 /sec
                 345      page-faults                      /                #   43.053 /sec
         782,326,119      cycles                           /                #    0.098 GHz
         471,645,724      instructions                     /                #    0.60  insn per cycle
          94,963,430      branches                         /                #   11.851 M/sec
           3,685,511      branch-misses                    /                #    3.88% of all branches

         1.001864539 seconds time elapsed

Committer notes:

As a reminder, to test with BPF counters one has to use BUILD_BPF_SKEL=1
in the make command line and have clang/llvm installed when building
perf, otherwise the --bpf-counters option will not be available:

  # perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1
  Error: unknown option `bpf-counters'

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

      -a, --all-cpus        system-wide collection from all CPUs
  &lt;SNIP&gt;
  #

Fixes: bb1c15b60b981d10 ("perf stat: Support regex pattern in --for-each-cgroup")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: bpf@vger.kernel.org
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Link: https://lore.kernel.org/r/20230104064402.1551516-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The --for-each-cgroup can have the same cgroup multiple times, but this
confuses BPF counters (since they have the same cgroup id), making only
the last cgroup events to be counted.

Let's check the cgroup name before adding a new entry to the cgroups
list.

Before:

  $ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1

   Performance counter stats for 'system wide':

       &lt;not counted&gt; msec cpu-clock                        /
       &lt;not counted&gt;      context-switches                 /
       &lt;not counted&gt;      cpu-migrations                   /
       &lt;not counted&gt;      page-faults                      /
       &lt;not counted&gt;      cycles                           /
       &lt;not counted&gt;      instructions                     /
       &lt;not counted&gt;      branches                         /
       &lt;not counted&gt;      branch-misses                    /
            8,016.04 msec cpu-clock                        /                #    7.998 CPUs utilized
               6,152      context-switches                 /                #  767.461 /sec
                 250      cpu-migrations                   /                #   31.187 /sec
                 442      page-faults                      /                #   55.139 /sec
         613,111,487      cycles                           /                #    0.076 GHz
         280,599,604      instructions                     /                #    0.46  insn per cycle
          57,692,724      branches                         /                #    7.197 M/sec
           3,385,168      branch-misses                    /                #    5.87% of all branches

         1.002220125 seconds time elapsed

After it becomes similar to the non-BPF mode:

  $ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/  sleep 1

   Performance counter stats for 'system wide':

            8,013.38 msec cpu-clock                        /                #    7.998 CPUs utilized
               6,859      context-switches                 /                #  855.944 /sec
                 334      cpu-migrations                   /                #   41.680 /sec
                 345      page-faults                      /                #   43.053 /sec
         782,326,119      cycles                           /                #    0.098 GHz
         471,645,724      instructions                     /                #    0.60  insn per cycle
          94,963,430      branches                         /                #   11.851 M/sec
           3,685,511      branch-misses                    /                #    3.88% of all branches

         1.001864539 seconds time elapsed

Committer notes:

As a reminder, to test with BPF counters one has to use BUILD_BPF_SKEL=1
in the make command line and have clang/llvm installed when building
perf, otherwise the --bpf-counters option will not be available:

  # perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1
  Error: unknown option `bpf-counters'

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

      -a, --all-cpus        system-wide collection from all CPUs
  &lt;SNIP&gt;
  #

Fixes: bb1c15b60b981d10 ("perf stat: Support regex pattern in --for-each-cgroup")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: bpf@vger.kernel.org
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Link: https://lore.kernel.org/r/20230104064402.1551516-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf stat: Fix handling of unsupported cgroup events when using BPF counters</title>
<updated>2023-01-04T13:52:07+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-01-04T06:44:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2d656b0f81b22101db0447f890e39fdd736b745e'/>
<id>2d656b0f81b22101db0447f890e39fdd736b745e</id>
<content type='text'>
When --for-each-cgroup option is used, it fails when any of events is
not supported and exits immediately.  This is not how 'perf stat'
handles unsupported events.

Let's ignore the failure and proceed with others so that the output is
similar to when BPF counters are not used:

Before:

  $ sudo ./perf stat -a --bpf-counters -e L1-icache-loads,L1-dcache-loads --for-each-cgroup system.slice,user.slice sleep 1
  Failed to open first cgroup events
  $

After it shows output similat to when --bpf-counters isn't specified:

  $ sudo ./perf stat -a --bpf-counters -e L1-icache-loads,L1-dcache-loads --for-each-cgroup system.slice,user.slice sleep 1

   Performance counter stats for 'system wide':

     &lt;not supported&gt;      L1-icache-loads                  system.slice
          29,892,418      L1-dcache-loads                  system.slice
     &lt;not supported&gt;      L1-icache-loads                  user.slice
          52,497,220      L1-dcache-loads                  user.slice
  $

Fixes: 944138f048f7d759 ("perf stat: Enable BPF counter with --for-each-cgroup")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Link: https://lore.kernel.org/r/20230104064402.1551516-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When --for-each-cgroup option is used, it fails when any of events is
not supported and exits immediately.  This is not how 'perf stat'
handles unsupported events.

Let's ignore the failure and proceed with others so that the output is
similar to when BPF counters are not used:

Before:

  $ sudo ./perf stat -a --bpf-counters -e L1-icache-loads,L1-dcache-loads --for-each-cgroup system.slice,user.slice sleep 1
  Failed to open first cgroup events
  $

After it shows output similat to when --bpf-counters isn't specified:

  $ sudo ./perf stat -a --bpf-counters -e L1-icache-loads,L1-dcache-loads --for-each-cgroup system.slice,user.slice sleep 1

   Performance counter stats for 'system wide':

     &lt;not supported&gt;      L1-icache-loads                  system.slice
          29,892,418      L1-dcache-loads                  system.slice
     &lt;not supported&gt;      L1-icache-loads                  user.slice
          52,497,220      L1-dcache-loads                  user.slice
  $

Fixes: 944138f048f7d759 ("perf stat: Enable BPF counter with --for-each-cgroup")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Link: https://lore.kernel.org/r/20230104064402.1551516-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test record_probe_libc_inet_pton: Fix test on s/390 where 'text_to_binary_address' now appears on the backtrace</title>
<updated>2023-01-04T13:04:08+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2022-12-28T14:57:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fb710ddee75fb96f50ee6d004ef777a0cf7ad5a3'/>
<id>fb710ddee75fb96f50ee6d004ef777a0cf7ad5a3</id>
<content type='text'>
perf test '84: probe libc's inet_pton &amp; backtrace it with ping' fails on
s390. Debugging revealed a changed stack trace for the ping command
using probes:

  ping 35729 [002]  8006.365063: probe_libc:inet_pton: (3ff9603e7c0)
                    13e7c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
            ---&gt;    104371 text_to_binary_address+0xef1 (inlined)
                    104371 gaih_inet+0xef1 (inlined)
                    104371 __GI_getaddrinfo+0xef1 (inlined)
                      5d4b main+0x139b (/usr/bin/ping)

The line "---&gt; text_to_binary_address ..." is new. It was introduced
with glibc version 2.36.7.2 released with Fedora 37 for s390.

Output before

  # perf test inet_pton
  84: probe libc's inet_pton &amp; backtrace it with ping   : FAILED!
  #

Output after:

  # perf test inet_pton
  84: probe libc's inet_pton &amp; backtrace it with ping   : Ok
  #

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20221228145704.2702487-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
perf test '84: probe libc's inet_pton &amp; backtrace it with ping' fails on
s390. Debugging revealed a changed stack trace for the ping command
using probes:

  ping 35729 [002]  8006.365063: probe_libc:inet_pton: (3ff9603e7c0)
                    13e7c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
            ---&gt;    104371 text_to_binary_address+0xef1 (inlined)
                    104371 gaih_inet+0xef1 (inlined)
                    104371 __GI_getaddrinfo+0xef1 (inlined)
                      5d4b main+0x139b (/usr/bin/ping)

The line "---&gt; text_to_binary_address ..." is new. It was introduced
with glibc version 2.36.7.2 released with Fedora 37 for s390.

Output before

  # perf test inet_pton
  84: probe libc's inet_pton &amp; backtrace it with ping   : FAILED!
  #

Output after:

  # perf test inet_pton
  84: probe libc's inet_pton &amp; backtrace it with ping   : Ok
  #

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20221228145704.2702487-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf lock contention: Fix core dump related to not finding the "__sched_text_end" symbol on s/390</title>
<updated>2023-01-03T18:48:23+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2022-12-30T10:26:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d8d85ce86dc82de4f88b821a78f533b9d5b22a45'/>
<id>d8d85ce86dc82de4f88b821a78f533b9d5b22a45</id>
<content type='text'>
The test case perf lock contention dumps core on s390. Run the following
commands:

  # ./perf lock record -- ./perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  # 20 sender and receiver processes per group
  # 10 groups == 400 processes run

      Total time: 2.799 [sec]
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.073 MB perf.data (100 samples) ]
  #
  # ./perf lock contention
  Segmentation fault (core dumped)
  #

The function call stack is lengthy, here are the top 5 functions:

  # gdb ./perf core.24048
  GNU gdb (GDB) Fedora Linux 12.1-6.fc37
  Core was generated by `./perf lock contention'.
  Program terminated with signal SIGSEGV, Segmentation fault.
  #0  0x00000000011dd25c in machine__is_lock_function (machine=0x3029e28, addr=1789230) at util/machine.c:3356
         3356 machine-&gt;sched.text_end = kmap-&gt;unmap_ip(kmap, sym-&gt;start);

 (gdb) where
  #0  0x00000000011dd25c in machine__is_lock_function (machine=0x3029e28, addr=1789230) at util/machine.c:3356
  #1  0x000000000109f244 in callchain_id (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:957
  #2  0x000000000109e094 in get_key_by_aggr_mode (key=0x3ffea4f7290, addr=27758136, evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:586
  #3  0x000000000109f4d0 in report_lock_contention_begin_event (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:1004
  #4  0x00000000010a00ae in evsel__process_contention_begin (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:1254
  #5  0x00000000010a0e14 in process_sample_event (tool=0x3ffea4f8480, event=0x3ff85601ef8, sample=0x3ffea4f77d0, evsel=0x30313e0, machine=0x3029e28) at builtin-lock.c:1464
  .....

The issue is in function machine__is_lock_function() in file
./util/machine.c lines 3355:

   /* should not fail from here */
   sym = machine__find_kernel_symbol_by_name(machine, "__sched_text_end", &amp;kmap);
   machine-&gt;sched.text_end = kmap-&gt;unmap_ip(kmap, sym-&gt;start)

On s390 the symbol __sched_text_end is *NOT* in the symbol list and the
resulting pointer sym is set to NULL. The sym-&gt;start is then a NULL pointer
access and generates the core dump.

The reason why __sched_text_end is not in the symbol list on s390 is
simple:

When the symbol list is created at perf start up with function calls

  dso__load
  +--&gt; dso__load_vmlinux_path
       +--&gt; dso__load_vmlinux
            +--&gt; dso__load_sym
	         +--&gt; dso__load_sym_internal (reads kernel symbols)
		 +--&gt; symbols__fixup_end
		 +--&gt; symbols__fixup_duplicate

The issue is in function symbols__fixup_duplicate(). It deletes all
symbols with have the same address. On s390:

  # nm -g  ~/linux/vmlinux| fgrep c68390
  0000000000c68390 T __cpuidle_text_start
  0000000000c68390 T __sched_text_end
  #

two symbols have identical addresses and __sched_text_end is considered
duplicate (in ascending sort order) and removed from the symbol list.
Therefore it is missing and an invalid pointer reference occurs.  The
code checks for symbol __sched_text_start and when it exists assumes
symbol __sched_text_end is also in the symbol table. However this is not
the case on s390.

Same situation exists for symbol __lock_text_start:

0000000000c68770 T __cpuidle_text_end
0000000000c68770 T __lock_text_start

This symbol is also removed from the symbol table but used in function
machine__is_lock_function().

To fix this and keep duplicate symbols in the symbol table, set
symbol_conf.allow_aliases to true. This prevents the removal of
duplicate symbols in function symbols__fixup_duplicate().

Output After:

 # ./perf lock contention
 contended total wait  max wait  avg wait    type   caller

        48   124.39 ms 123.99 ms   2.59 ms rwsem:W unlink_anon_vmas+0x24a
        47    83.68 ms  83.26 ms   1.78 ms rwsem:W free_pgtables+0x132
         5    41.22 us  10.55 us   8.24 us rwsem:W free_pgtables+0x140
         4    40.12 us  20.55 us  10.03 us rwsem:W copy_process+0x1ac8
 #

Fixes: 0d2997f750d1de39 ("perf lock: Look up callchain for the contended locks")
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20221230102627.2410847-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The test case perf lock contention dumps core on s390. Run the following
commands:

  # ./perf lock record -- ./perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  # 20 sender and receiver processes per group
  # 10 groups == 400 processes run

      Total time: 2.799 [sec]
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.073 MB perf.data (100 samples) ]
  #
  # ./perf lock contention
  Segmentation fault (core dumped)
  #

The function call stack is lengthy, here are the top 5 functions:

  # gdb ./perf core.24048
  GNU gdb (GDB) Fedora Linux 12.1-6.fc37
  Core was generated by `./perf lock contention'.
  Program terminated with signal SIGSEGV, Segmentation fault.
  #0  0x00000000011dd25c in machine__is_lock_function (machine=0x3029e28, addr=1789230) at util/machine.c:3356
         3356 machine-&gt;sched.text_end = kmap-&gt;unmap_ip(kmap, sym-&gt;start);

 (gdb) where
  #0  0x00000000011dd25c in machine__is_lock_function (machine=0x3029e28, addr=1789230) at util/machine.c:3356
  #1  0x000000000109f244 in callchain_id (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:957
  #2  0x000000000109e094 in get_key_by_aggr_mode (key=0x3ffea4f7290, addr=27758136, evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:586
  #3  0x000000000109f4d0 in report_lock_contention_begin_event (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:1004
  #4  0x00000000010a00ae in evsel__process_contention_begin (evsel=0x30313e0, sample=0x3ffea4f77d0) at builtin-lock.c:1254
  #5  0x00000000010a0e14 in process_sample_event (tool=0x3ffea4f8480, event=0x3ff85601ef8, sample=0x3ffea4f77d0, evsel=0x30313e0, machine=0x3029e28) at builtin-lock.c:1464
  .....

The issue is in function machine__is_lock_function() in file
./util/machine.c lines 3355:

   /* should not fail from here */
   sym = machine__find_kernel_symbol_by_name(machine, "__sched_text_end", &amp;kmap);
   machine-&gt;sched.text_end = kmap-&gt;unmap_ip(kmap, sym-&gt;start)

On s390 the symbol __sched_text_end is *NOT* in the symbol list and the
resulting pointer sym is set to NULL. The sym-&gt;start is then a NULL pointer
access and generates the core dump.

The reason why __sched_text_end is not in the symbol list on s390 is
simple:

When the symbol list is created at perf start up with function calls

  dso__load
  +--&gt; dso__load_vmlinux_path
       +--&gt; dso__load_vmlinux
            +--&gt; dso__load_sym
	         +--&gt; dso__load_sym_internal (reads kernel symbols)
		 +--&gt; symbols__fixup_end
		 +--&gt; symbols__fixup_duplicate

The issue is in function symbols__fixup_duplicate(). It deletes all
symbols with have the same address. On s390:

  # nm -g  ~/linux/vmlinux| fgrep c68390
  0000000000c68390 T __cpuidle_text_start
  0000000000c68390 T __sched_text_end
  #

two symbols have identical addresses and __sched_text_end is considered
duplicate (in ascending sort order) and removed from the symbol list.
Therefore it is missing and an invalid pointer reference occurs.  The
code checks for symbol __sched_text_start and when it exists assumes
symbol __sched_text_end is also in the symbol table. However this is not
the case on s390.

Same situation exists for symbol __lock_text_start:

0000000000c68770 T __cpuidle_text_end
0000000000c68770 T __lock_text_start

This symbol is also removed from the symbol table but used in function
machine__is_lock_function().

To fix this and keep duplicate symbols in the symbol table, set
symbol_conf.allow_aliases to true. This prevents the removal of
duplicate symbols in function symbols__fixup_duplicate().

Output After:

 # ./perf lock contention
 contended total wait  max wait  avg wait    type   caller

        48   124.39 ms 123.99 ms   2.59 ms rwsem:W unlink_anon_vmas+0x24a
        47    83.68 ms  83.26 ms   1.78 ms rwsem:W free_pgtables+0x132
         5    41.22 us  10.55 us   8.24 us rwsem:W free_pgtables+0x140
         4    40.12 us  20.55 us  10.03 us rwsem:W copy_process+0x1ac8
 #

Fixes: 0d2997f750d1de39 ("perf lock: Look up callchain for the contended locks")
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20221230102627.2410847-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf build: Don't propagate subdir to submakes for install_headers</title>
<updated>2023-01-03T18:35:01+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-01-03T07:09:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f89fb55714b620ff1352141a9f9315611f16573e'/>
<id>f89fb55714b620ff1352141a9f9315611f16573e</id>
<content type='text'>
subdir is added to the OUTPUT which fails as part of building
install_headers when passed from "make -C tools perf_install".

Committer testing:

The original reporter (see the Link: below) had trouble with this:

$ make -C tools perf_install

That ended up with errors like this:

  /var/home/acme/git/perf-urgent/tools/scripts/Makefile.include:17: *** output directory "/var/home/acme/git/perf-urgent/tools/perf/libperf/perf/" does not exist.  Stop.

With this patch applied we now get it installed at:

  INSTALL /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h

As expected:

  $ ls -la /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h
  -rw-r--r--. 1 acme acme 1146 Jan  3 15:42 /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h

And if we clean tools with:

  $ make -C tools clean

it gets cleaned up:

  $ ls -la /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h
  ls: cannot access '/var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h': No such file or directory
  $

Fixes: 746bd29e348f99b4 ("perf build: Use tools/lib headers from install path")
Reported-by: Torsten Hilbrich &lt;torsten.hilbrich@secunet.com&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/fa4b3115-d555-3d7f-54d1-018002e99350@secunet.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
subdir is added to the OUTPUT which fails as part of building
install_headers when passed from "make -C tools perf_install".

Committer testing:

The original reporter (see the Link: below) had trouble with this:

$ make -C tools perf_install

That ended up with errors like this:

  /var/home/acme/git/perf-urgent/tools/scripts/Makefile.include:17: *** output directory "/var/home/acme/git/perf-urgent/tools/perf/libperf/perf/" does not exist.  Stop.

With this patch applied we now get it installed at:

  INSTALL /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h

As expected:

  $ ls -la /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h
  -rw-r--r--. 1 acme acme 1146 Jan  3 15:42 /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h

And if we clean tools with:

  $ make -C tools clean

it gets cleaned up:

  $ ls -la /var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h
  ls: cannot access '/var/home/acme/git/perf-urgent/tools/perf/libperf/include/perf/bpf_perf.h': No such file or directory
  $

Fixes: 746bd29e348f99b4 ("perf build: Use tools/lib headers from install path")
Reported-by: Torsten Hilbrich &lt;torsten.hilbrich@secunet.com&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/fa4b3115-d555-3d7f-54d1-018002e99350@secunet.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test record_probe_libc_inet_pton: Fix failure due to extra inet_pton() backtrace in glibc &gt;= 2.35</title>
<updated>2023-01-03T13:47:43+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-01-03T13:21:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b963c1d6261eb7fba1ba14074fb447521be84add'/>
<id>b963c1d6261eb7fba1ba14074fb447521be84add</id>
<content type='text'>
Starting with glibc 2.35 there are extra inet_pton() calls when doing a
IPv6 ping as in one of the 'perf test' entry, which makes it fail:

  # perf test inet_pton
  89: probe libc's inet_pton &amp; backtrace it with ping   : FAILED!
  #

If we look at what this script is expecting (commenting out the removal
of the temporary files in it):

  # cat /tmp/expected.aT6
  ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)
  .*inet_pton\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6|inlined\)$
  getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6\)$
  .*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$
  #

And looking at what we are getting out of 'perf script', to match with
the above:

  # cat /tmp/perf.script.IUC
  ping 623883 [006] 265438.471610: probe_libc:inet_pton: (7f32bcf314c0)
                    1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
                     29510 __libc_start_call_main+0x80 (/usr/lib64/libc.so.6)

  ping 623883 [006] 265438.471664: probe_libc:inet_pton: (7f32bcf314c0)
                    1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
                     fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6)
                      491e [unknown] (/usr/bin/ping)
  #

We see that its just the first call to inet_pton() that didn't came thru
getaddrinfo(), so if we ignore the first the script matches what it
expects, testing that using 'perf probe' + 'perf record' + 'perf script'
with callchains on userspace targets is producing the expected results.

Since we don't have a 'perf script --skip' to help us here, use tac +
grep to do that, resulting in a one liner that makes this script work on
both older glibc versions as well as with 2.35.

With it, on fedora 36, x86, glibc 2.35:

  # perf test inet_pton
   90: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  # perf test -v inet_pton
   90: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 627197
  ping 627220 1 267956.962402: probe_libc:inet_pton_1: (7f488bf314c0)
  1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
  fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6)
  491e n (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  #

And on Ubuntu 22.04.1 LTS on a Libre Computer ROC-RK3399-PC arm64 system:

Before this patch it works (see that the script used has no 'tac' to
remove the first event):

  root@roc-rk3399-pc:~# dpkg -l | grep libc-bin
  ii  libc-bin                                2.35-0ubuntu3.1                         arm64        GNU C Library: Binaries
  root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh
  root@roc-rk3399-pc:~# perf test inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  root@roc-rk3399-pc:~# perf test -v inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 1375
  ping 1399 [000] 4114.417450: probe_libc:inet_pton: (ffffb3e26120)
  106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6)
  d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6)
  2b68 [unknown] (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  root@roc-rk3399-pc:~#

And after it continues to work:

  root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh
  	perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac &gt; $perf_script
  root@roc-rk3399-pc:~# perf test inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  root@roc-rk3399-pc:~# perf test -v inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 6995
  ping 7019 [005] 4832.160741: probe_libc:inet_pton: (ffffa62e6120)
  106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6)
  d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6)
  2b68 [unknown] (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  root@roc-rk3399-pc:~#

Reported-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/Y7QyPkPlDYip3cZH@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Starting with glibc 2.35 there are extra inet_pton() calls when doing a
IPv6 ping as in one of the 'perf test' entry, which makes it fail:

  # perf test inet_pton
  89: probe libc's inet_pton &amp; backtrace it with ping   : FAILED!
  #

If we look at what this script is expecting (commenting out the removal
of the temporary files in it):

  # cat /tmp/expected.aT6
  ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)
  .*inet_pton\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6|inlined\)$
  getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\(/usr/lib64/libc.so.6\)$
  .*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$
  #

And looking at what we are getting out of 'perf script', to match with
the above:

  # cat /tmp/perf.script.IUC
  ping 623883 [006] 265438.471610: probe_libc:inet_pton: (7f32bcf314c0)
                    1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
                     29510 __libc_start_call_main+0x80 (/usr/lib64/libc.so.6)

  ping 623883 [006] 265438.471664: probe_libc:inet_pton: (7f32bcf314c0)
                    1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
                     fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6)
                      491e [unknown] (/usr/bin/ping)
  #

We see that its just the first call to inet_pton() that didn't came thru
getaddrinfo(), so if we ignore the first the script matches what it
expects, testing that using 'perf probe' + 'perf record' + 'perf script'
with callchains on userspace targets is producing the expected results.

Since we don't have a 'perf script --skip' to help us here, use tac +
grep to do that, resulting in a one liner that makes this script work on
both older glibc versions as well as with 2.35.

With it, on fedora 36, x86, glibc 2.35:

  # perf test inet_pton
   90: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  # perf test -v inet_pton
   90: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 627197
  ping 627220 1 267956.962402: probe_libc:inet_pton_1: (7f488bf314c0)
  1314c0 __GI___inet_pton+0x0 (/usr/lib64/libc.so.6)
  fa6c6 getaddrinfo+0x126 (/usr/lib64/libc.so.6)
  491e n (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  #

And on Ubuntu 22.04.1 LTS on a Libre Computer ROC-RK3399-PC arm64 system:

Before this patch it works (see that the script used has no 'tac' to
remove the first event):

  root@roc-rk3399-pc:~# dpkg -l | grep libc-bin
  ii  libc-bin                                2.35-0ubuntu3.1                         arm64        GNU C Library: Binaries
  root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh
  root@roc-rk3399-pc:~# perf test inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  root@roc-rk3399-pc:~# perf test -v inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 1375
  ping 1399 [000] 4114.417450: probe_libc:inet_pton: (ffffb3e26120)
  106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6)
  d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6)
  2b68 [unknown] (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  root@roc-rk3399-pc:~#

And after it continues to work:

  root@roc-rk3399-pc:~# grep -w tac ~acme/libexec/perf-core/tests/shell/record+probe_libc_inet_pton.sh
  	perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac &gt; $perf_script
  root@roc-rk3399-pc:~# perf test inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 : Ok
  root@roc-rk3399-pc:~# perf test -v inet_pton
   86: probe libc's inet_pton &amp; backtrace it with ping                 :
  --- start ---
  test child forked, pid 6995
  ping 7019 [005] 4832.160741: probe_libc:inet_pton: (ffffa62e6120)
  106120 inet_pton+0x0 (/usr/lib/aarch64-linux-gnu/libc.so.6)
  d18bc getaddrinfo+0xec (/usr/lib/aarch64-linux-gnu/libc.so.6)
  2b68 [unknown] (/usr/bin/ping)
  test child finished with 0
  ---- end ----
  probe libc's inet_pton &amp; backtrace it with ping: Ok
  root@roc-rk3399-pc:~#

Reported-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/Y7QyPkPlDYip3cZH@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Fix segfault when trying to process tracepoints in perf.data and not linked with libtraceevent</title>
<updated>2023-01-02T16:45:19+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-01-02T16:06:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=77fe30fed1c0cd282eadb0728999ea3d3350e0b0'/>
<id>77fe30fed1c0cd282eadb0728999ea3d3350e0b0</id>
<content type='text'>
When we have a perf.data file with tracepoints, such as:

  # perf evlist -f
  probe_perf:lzma_decompress_to_file
  # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
  #

We end up segfaulting when using perf built with NO_LIBTRACEEVENT=1 by
trying to find an evsel with a NULL 'event_name' variable:

  (gdb) run report --stdio -f
  Starting program: /root/bin/perf report --stdio -f

  Program received signal SIGSEGV, Segmentation fault.
  0x000000000055219d in find_evsel (evlist=0xfda7b0, event_name=0x0) at util/sort.c:2830
  warning: Source file is more recent than executable.
  2830		if (event_name[0] == '%') {
  Missing separate debuginfos, use: dnf debuginfo-install bzip2-libs-1.0.8-11.fc36.x86_64 cyrus-sasl-lib-2.1.27-18.fc36.x86_64 elfutils-debuginfod-client-0.188-3.fc36.x86_64 elfutils-libelf-0.188-3.fc36.x86_64 elfutils-libs-0.188-3.fc36.x86_64 glibc-2.35-20.fc36.x86_64 keyutils-libs-1.6.1-4.fc36.x86_64 krb5-libs-1.19.2-12.fc36.x86_64 libbrotli-1.0.9-7.fc36.x86_64 libcap-2.48-4.fc36.x86_64 libcom_err-1.46.5-2.fc36.x86_64 libcurl-7.82.0-12.fc36.x86_64 libevent-2.1.12-6.fc36.x86_64 libgcc-12.2.1-4.fc36.x86_64 libidn2-2.3.4-1.fc36.x86_64 libnghttp2-1.51.0-1.fc36.x86_64 libpsl-0.21.1-5.fc36.x86_64 libselinux-3.3-4.fc36.x86_64 libssh-0.9.6-4.fc36.x86_64 libstdc++-12.2.1-4.fc36.x86_64 libunistring-1.0-1.fc36.x86_64 libunwind-1.6.2-2.fc36.x86_64 libxcrypt-4.4.33-4.fc36.x86_64 libzstd-1.5.2-2.fc36.x86_64 numactl-libs-2.0.14-5.fc36.x86_64 opencsd-1.2.0-1.fc36.x86_64 openldap-2.6.3-1.fc36.x86_64 openssl-libs-3.0.5-2.fc36.x86_64 slang-2.3.2-11.fc36.x86_64 xz-libs-5.2.5-9.fc36.x86_64 zlib-1.2.11-33.fc36.x86_64
  (gdb) bt
  #0  0x000000000055219d in find_evsel (evlist=0xfda7b0, event_name=0x0) at util/sort.c:2830
  #1  0x0000000000552416 in add_dynamic_entry (evlist=0xfda7b0, tok=0xffb6eb "trace", level=2) at util/sort.c:2976
  #2  0x0000000000552d26 in sort_dimension__add (list=0xf93e00 &lt;perf_hpp_list&gt;, tok=0xffb6eb "trace", evlist=0xfda7b0, level=2) at util/sort.c:3193
  #3  0x0000000000552e1c in setup_sort_list (list=0xf93e00 &lt;perf_hpp_list&gt;, str=0xffb6eb "trace", evlist=0xfda7b0) at util/sort.c:3227
  #4  0x00000000005532fa in __setup_sorting (evlist=0xfda7b0) at util/sort.c:3381
  #5  0x0000000000553cdc in setup_sorting (evlist=0xfda7b0) at util/sort.c:3608
  #6  0x000000000042eb9f in cmd_report (argc=0, argv=0x7fffffffe470) at builtin-report.c:1596
  #7  0x00000000004aee7e in run_builtin (p=0xf64ca0 &lt;commands+288&gt;, argc=3, argv=0x7fffffffe470) at perf.c:330
  #8  0x00000000004af0f2 in handle_internal_command (argc=3, argv=0x7fffffffe470) at perf.c:384
  #9  0x00000000004af241 in run_argv (argcp=0x7fffffffe29c, argv=0x7fffffffe290) at perf.c:428
  #10 0x00000000004af5fc in main (argc=3, argv=0x7fffffffe470) at perf.c:562
  (gdb)

So check if we have tracepoint events in add_dynamic_entry() and bail
out instead:

  # perf report --stdio -f
  This perf binary isn't linked with libtraceevent, can't process probe_perf:lzma_decompress_to_file
  Error:
  Unknown --sort key: `trace'
  #

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/Y7MDb7kRaHZB6APC@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When we have a perf.data file with tracepoints, such as:

  # perf evlist -f
  probe_perf:lzma_decompress_to_file
  # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
  #

We end up segfaulting when using perf built with NO_LIBTRACEEVENT=1 by
trying to find an evsel with a NULL 'event_name' variable:

  (gdb) run report --stdio -f
  Starting program: /root/bin/perf report --stdio -f

  Program received signal SIGSEGV, Segmentation fault.
  0x000000000055219d in find_evsel (evlist=0xfda7b0, event_name=0x0) at util/sort.c:2830
  warning: Source file is more recent than executable.
  2830		if (event_name[0] == '%') {
  Missing separate debuginfos, use: dnf debuginfo-install bzip2-libs-1.0.8-11.fc36.x86_64 cyrus-sasl-lib-2.1.27-18.fc36.x86_64 elfutils-debuginfod-client-0.188-3.fc36.x86_64 elfutils-libelf-0.188-3.fc36.x86_64 elfutils-libs-0.188-3.fc36.x86_64 glibc-2.35-20.fc36.x86_64 keyutils-libs-1.6.1-4.fc36.x86_64 krb5-libs-1.19.2-12.fc36.x86_64 libbrotli-1.0.9-7.fc36.x86_64 libcap-2.48-4.fc36.x86_64 libcom_err-1.46.5-2.fc36.x86_64 libcurl-7.82.0-12.fc36.x86_64 libevent-2.1.12-6.fc36.x86_64 libgcc-12.2.1-4.fc36.x86_64 libidn2-2.3.4-1.fc36.x86_64 libnghttp2-1.51.0-1.fc36.x86_64 libpsl-0.21.1-5.fc36.x86_64 libselinux-3.3-4.fc36.x86_64 libssh-0.9.6-4.fc36.x86_64 libstdc++-12.2.1-4.fc36.x86_64 libunistring-1.0-1.fc36.x86_64 libunwind-1.6.2-2.fc36.x86_64 libxcrypt-4.4.33-4.fc36.x86_64 libzstd-1.5.2-2.fc36.x86_64 numactl-libs-2.0.14-5.fc36.x86_64 opencsd-1.2.0-1.fc36.x86_64 openldap-2.6.3-1.fc36.x86_64 openssl-libs-3.0.5-2.fc36.x86_64 slang-2.3.2-11.fc36.x86_64 xz-libs-5.2.5-9.fc36.x86_64 zlib-1.2.11-33.fc36.x86_64
  (gdb) bt
  #0  0x000000000055219d in find_evsel (evlist=0xfda7b0, event_name=0x0) at util/sort.c:2830
  #1  0x0000000000552416 in add_dynamic_entry (evlist=0xfda7b0, tok=0xffb6eb "trace", level=2) at util/sort.c:2976
  #2  0x0000000000552d26 in sort_dimension__add (list=0xf93e00 &lt;perf_hpp_list&gt;, tok=0xffb6eb "trace", evlist=0xfda7b0, level=2) at util/sort.c:3193
  #3  0x0000000000552e1c in setup_sort_list (list=0xf93e00 &lt;perf_hpp_list&gt;, str=0xffb6eb "trace", evlist=0xfda7b0) at util/sort.c:3227
  #4  0x00000000005532fa in __setup_sorting (evlist=0xfda7b0) at util/sort.c:3381
  #5  0x0000000000553cdc in setup_sorting (evlist=0xfda7b0) at util/sort.c:3608
  #6  0x000000000042eb9f in cmd_report (argc=0, argv=0x7fffffffe470) at builtin-report.c:1596
  #7  0x00000000004aee7e in run_builtin (p=0xf64ca0 &lt;commands+288&gt;, argc=3, argv=0x7fffffffe470) at perf.c:330
  #8  0x00000000004af0f2 in handle_internal_command (argc=3, argv=0x7fffffffe470) at perf.c:384
  #9  0x00000000004af241 in run_argv (argcp=0x7fffffffe29c, argv=0x7fffffffe290) at perf.c:428
  #10 0x00000000004af5fc in main (argc=3, argv=0x7fffffffe470) at perf.c:562
  (gdb)

So check if we have tracepoint events in add_dynamic_entry() and bail
out instead:

  # perf report --stdio -f
  This perf binary isn't linked with libtraceevent, can't process probe_perf:lzma_decompress_to_file
  Error:
  Unknown --sort key: `trace'
  #

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/Y7MDb7kRaHZB6APC@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Don't include signature in version strings</title>
<updated>2023-01-02T15:34:06+00:00</updated>
<author>
<name>Ahelenia Ziemiańska</name>
<email>nabijaczleweli@nabijaczleweli.xyz</email>
</author>
<published>2022-12-27T20:58:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f24fb53984cfba42ff72a47466eabfd772da647b'/>
<id>f24fb53984cfba42ff72a47466eabfd772da647b</id>
<content type='text'>
This explodes the build if HEAD is signed, since the generated version
is gpg: Signature made Mon 26 Dec 2022 20:34:48 CET, then a few more
lines, then the SHA.

Signed-off-by: Ahelenia Ziemiańska &lt;nabijaczleweli@nabijaczleweli.xyz&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/7c9637711271f50ec2341fb8a7c29585335dab04.1672174189.git.nabijaczleweli@nabijaczleweli.xyz
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This explodes the build if HEAD is signed, since the generated version
is gpg: Signature made Mon 26 Dec 2022 20:34:48 CET, then a few more
lines, then the SHA.

Signed-off-by: Ahelenia Ziemiańska &lt;nabijaczleweli@nabijaczleweli.xyz&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/7c9637711271f50ec2341fb8a7c29585335dab04.1672174189.git.nabijaczleweli@nabijaczleweli.xyz
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf help: Use HAVE_LIBTRACEEVENT to filter out unsupported commands</title>
<updated>2023-01-02T14:51:53+00:00</updated>
<author>
<name>Yang Jihong</name>
<email>yangjihong1@huawei.com</email>
</author>
<published>2022-12-26T08:57:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=55c41f2e4f7e81e48f3ecc9fba1e316e770213f2'/>
<id>55c41f2e4f7e81e48f3ecc9fba1e316e770213f2</id>
<content type='text'>
Commands such as kmem, kwork, lock, sched, trace and timechart depend on
libtraceevent, these commands need to be isolated using HAVE_LIBTRACEEVENT
macro when cmdlist generation.

The output of the generate-cmdlist.sh script is as follows:

  # ./util/generate-cmdlist.sh
  /* Automatically generated by ./util/generate-cmdlist.sh */
  struct cmdname_help
  {
      char name[16];
      char help[80];
  };

  static struct cmdname_help common_cmds[] = {
    {"annotate", "Read perf.data (created by perf record) and display annotated code"},
    {"archive", "Create archive with object files with build-ids found in perf.data file"},
    {"bench", "General framework for benchmark suites"},
    {"buildid-cache", "Manage build-id cache."},
    {"buildid-list", "List the buildids in a perf.data file"},
    {"c2c", "Shared Data C2C/HITM Analyzer."},
    {"config", "Get and set variables in a configuration file."},
    {"daemon", "Run record sessions on background"},
    {"data", "Data file related processing"},
    {"diff", "Read perf.data files and display the differential profile"},
    {"evlist", "List the event names in a perf.data file"},
    {"ftrace", "simple wrapper for kernel's ftrace functionality"},
    {"inject", "Filter to augment the events stream with additional information"},
    {"iostat", "Show I/O performance metrics"},
    {"kallsyms", "Searches running kernel for symbols"},
    {"kvm", "Tool to trace/measure kvm guest os"},
    {"list", "List all symbolic event types"},
    {"mem", "Profile memory accesses"},
    {"record", "Run a command and record its profile into perf.data"},
    {"report", "Read perf.data (created by perf record) and display the profile"},
    {"script", "Read perf.data (created by perf record) and display trace output"},
    {"stat", "Run a command and gather performance counter statistics"},
    {"test", "Runs sanity tests."},
    {"top", "System profiling tool."},
    {"version", "display the version of perf binary"},
  #ifdef HAVE_LIBELF_SUPPORT
    {"probe", "Define new dynamic tracepoints"},
  #endif /* HAVE_LIBELF_SUPPORT */
  #if defined(HAVE_LIBTRACEEVENT) &amp;&amp; (defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT))
    {"trace", "strace inspired tool"},
  #endif /* HAVE_LIBTRACEEVENT &amp;&amp; (HAVE_LIBAUDIT_SUPPORT || HAVE_SYSCALL_TABLE_SUPPORT) */
  #ifdef HAVE_LIBTRACEEVENT
    {"kmem", "Tool to trace/measure kernel memory properties"},
    {"kwork", "Tool to trace/measure kernel work properties (latencies)"},
    {"lock", "Analyze lock events"},
    {"sched", "Tool to trace/measure scheduler properties (latencies)"},
    {"timechart", "Tool to visualize total system behavior during a workload"},
  #endif /* HAVE_LIBTRACEEVENT */
  };

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20221226085703.95081-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commands such as kmem, kwork, lock, sched, trace and timechart depend on
libtraceevent, these commands need to be isolated using HAVE_LIBTRACEEVENT
macro when cmdlist generation.

The output of the generate-cmdlist.sh script is as follows:

  # ./util/generate-cmdlist.sh
  /* Automatically generated by ./util/generate-cmdlist.sh */
  struct cmdname_help
  {
      char name[16];
      char help[80];
  };

  static struct cmdname_help common_cmds[] = {
    {"annotate", "Read perf.data (created by perf record) and display annotated code"},
    {"archive", "Create archive with object files with build-ids found in perf.data file"},
    {"bench", "General framework for benchmark suites"},
    {"buildid-cache", "Manage build-id cache."},
    {"buildid-list", "List the buildids in a perf.data file"},
    {"c2c", "Shared Data C2C/HITM Analyzer."},
    {"config", "Get and set variables in a configuration file."},
    {"daemon", "Run record sessions on background"},
    {"data", "Data file related processing"},
    {"diff", "Read perf.data files and display the differential profile"},
    {"evlist", "List the event names in a perf.data file"},
    {"ftrace", "simple wrapper for kernel's ftrace functionality"},
    {"inject", "Filter to augment the events stream with additional information"},
    {"iostat", "Show I/O performance metrics"},
    {"kallsyms", "Searches running kernel for symbols"},
    {"kvm", "Tool to trace/measure kvm guest os"},
    {"list", "List all symbolic event types"},
    {"mem", "Profile memory accesses"},
    {"record", "Run a command and record its profile into perf.data"},
    {"report", "Read perf.data (created by perf record) and display the profile"},
    {"script", "Read perf.data (created by perf record) and display trace output"},
    {"stat", "Run a command and gather performance counter statistics"},
    {"test", "Runs sanity tests."},
    {"top", "System profiling tool."},
    {"version", "display the version of perf binary"},
  #ifdef HAVE_LIBELF_SUPPORT
    {"probe", "Define new dynamic tracepoints"},
  #endif /* HAVE_LIBELF_SUPPORT */
  #if defined(HAVE_LIBTRACEEVENT) &amp;&amp; (defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT))
    {"trace", "strace inspired tool"},
  #endif /* HAVE_LIBTRACEEVENT &amp;&amp; (HAVE_LIBAUDIT_SUPPORT || HAVE_SYSCALL_TABLE_SUPPORT) */
  #ifdef HAVE_LIBTRACEEVENT
    {"kmem", "Tool to trace/measure kernel memory properties"},
    {"kwork", "Tool to trace/measure kernel work properties (latencies)"},
    {"lock", "Analyze lock events"},
    {"sched", "Tool to trace/measure scheduler properties (latencies)"},
    {"timechart", "Tool to visualize total system behavior during a workload"},
  #endif /* HAVE_LIBTRACEEVENT */
  };

Fixes: 378ef0f5d9d7f465 ("perf build: Use libtraceevent from the system")
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20221226085703.95081-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
