<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools/perf/util, branch v5.12.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>perf map: Fix error return code in maps__clone()</title>
<updated>2021-04-23T19:03:09+00:00</updated>
<author>
<name>Zhen Lei</name>
<email>thunder.leizhen@huawei.com</email>
</author>
<published>2021-04-15T09:27:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c6f87141254d16e281e4b4431af7316895207b8f'/>
<id>c6f87141254d16e281e4b4431af7316895207b8f</id>
<content type='text'>
Although 'err' has been initialized to -ENOMEM, but it will be reassigned
by the "err = unwind__prepare_access(...)" statement in the for loop. So
that, the value of 'err' is unknown when map__clone() failed.

Fixes: 6c502584438bda63 ("perf unwind: Call unwind__prepare_access for forked thread")
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Zhen Lei &lt;thunder.leizhen@huawei.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: zhen lei &lt;thunder.leizhen@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20210415092744.3793-1-thunder.leizhen@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>
Although 'err' has been initialized to -ENOMEM, but it will be reassigned
by the "err = unwind__prepare_access(...)" statement in the for loop. So
that, the value of 'err' is unknown when map__clone() failed.

Fixes: 6c502584438bda63 ("perf unwind: Call unwind__prepare_access for forked thread")
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Zhen Lei &lt;thunder.leizhen@huawei.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: zhen lei &lt;thunder.leizhen@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20210415092744.3793-1-thunder.leizhen@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf auxtrace: Fix potential NULL pointer dereference</title>
<updated>2021-04-23T18:34:32+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2021-04-20T15:15:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b14585d9f18dc617e975815570fe836be656b1da'/>
<id>b14585d9f18dc617e975815570fe836be656b1da</id>
<content type='text'>
In the function auxtrace_parse_snapshot_options(), the callback pointer
"itr-&gt;parse_snapshot_options" can be NULL if it has not been set during
the AUX record initialization.  This can cause tool crashing if the
callback pointer "itr-&gt;parse_snapshot_options" is dereferenced without
performing NULL check.

Add a NULL check for the pointer "itr-&gt;parse_snapshot_options" before
invoke the callback.

Fixes: d20031bb63dd6dde ("perf tools: Add AUX area tracing Snapshot Mode")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Link: http://lore.kernel.org/lkml/20210420151554.2031768-1-leo.yan@linaro.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>
In the function auxtrace_parse_snapshot_options(), the callback pointer
"itr-&gt;parse_snapshot_options" can be NULL if it has not been set during
the AUX record initialization.  This can cause tool crashing if the
callback pointer "itr-&gt;parse_snapshot_options" is dereferenced without
performing NULL check.

Add a NULL check for the pointer "itr-&gt;parse_snapshot_options" before
invoke the callback.

Fixes: d20031bb63dd6dde ("perf tools: Add AUX area tracing Snapshot Mode")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Link: http://lore.kernel.org/lkml/20210420151554.2031768-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf data: Fix error return code in perf_data__create_dir()</title>
<updated>2021-04-20T17:46:48+00:00</updated>
<author>
<name>Zhen Lei</name>
<email>thunder.leizhen@huawei.com</email>
</author>
<published>2021-04-15T08:34:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f2211881e737cade55e0ee07cf6a26d91a35a6fe'/>
<id>f2211881e737cade55e0ee07cf6a26d91a35a6fe</id>
<content type='text'>
Although 'ret' has been initialized to -1, but it will be reassigned by
the "ret = open(...)" statement in the for loop. So that, the value of
'ret' is unknown when asprintf() failed.

Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Zhen Lei &lt;thunder.leizhen@huawei.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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: http://lore.kernel.org/lkml/20210415083417.3740-1-thunder.leizhen@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>
Although 'ret' has been initialized to -1, but it will be reassigned by
the "ret = open(...)" statement in the for loop. So that, the value of
'ret' is unknown when asprintf() failed.

Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Zhen Lei &lt;thunder.leizhen@huawei.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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: http://lore.kernel.org/lkml/20210415083417.3740-1-thunder.leizhen@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf arm-spe: Avoid potential buffer overrun</title>
<updated>2021-04-07T19:23:20+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2021-04-07T15:39:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=92f1e8adf7db2ef9b90e5662182810c0cf8ac22e'/>
<id>92f1e8adf7db2ef9b90e5662182810c0cf8ac22e</id>
<content type='text'>
SPE extended headers are &gt; 1 byte so ensure the buffer contains at least
this before reading. This issue was detected by fuzzing.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andre Przywara &lt;andre.przywara@arm.com&gt;
Cc: Dave Martin &lt;dave.martin@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.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;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20210407153955.317215-1-irogers@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>
SPE extended headers are &gt; 1 byte so ensure the buffer contains at least
this before reading. This issue was detected by fuzzing.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andre Przywara &lt;andre.przywara@arm.com&gt;
Cc: Dave Martin &lt;dave.martin@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.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;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20210407153955.317215-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf report: Fix wrong LBR block sorting</title>
<updated>2021-04-07T19:18:49+00:00</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2021-04-07T02:44:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f2013278ae40b89cc27916366c407ce5261815ef'/>
<id>f2013278ae40b89cc27916366c407ce5261815ef</id>
<content type='text'>
When '--total-cycles' is specified, it supports sorting for all blocks
by 'Sampled Cycles%'. This is useful to concentrate on the globally
hottest blocks.

'Sampled Cycles%' - block sampled cycles aggregation / total sampled cycles

But in current code, it doesn't use the cycles aggregation. Part of
'cycles' counting is possibly dropped for some overlap jumps. But for
identifying the hot block, we always need the full cycles.

  # perf record -b ./triad_loop
  # perf report --total-cycles --stdio

Before:

  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles                                          [Program Block Range]      Shared Object
  # ...............  ..............  ...........  ..........  .............................................................  .................
  #
              0.81%             793        4.32%         793                           [setup-vdso.h:34 -&gt; setup-vdso.h:40]         ld-2.27.so
              0.49%             480        0.87%         160                    [native_write_msr+0 -&gt; native_write_msr+16]  [kernel.kallsyms]
              0.48%             476        0.52%          95                      [native_read_msr+0 -&gt; native_read_msr+29]  [kernel.kallsyms]
              0.31%             303        1.65%         303                              [nmi_restore+0 -&gt; nmi_restore+37]  [kernel.kallsyms]
              0.26%             255        1.39%         255      [nohz_balance_exit_idle+75 -&gt; nohz_balance_exit_idle+162]  [kernel.kallsyms]
              0.24%             234        1.28%         234                       [end_repeat_nmi+67 -&gt; end_repeat_nmi+83]  [kernel.kallsyms]
              0.23%             227        1.24%         227            [__irqentry_text_end+96 -&gt; __irqentry_text_end+126]  [kernel.kallsyms]
              0.20%             194        1.06%         194             [native_set_debugreg+52 -&gt; native_set_debugreg+56]  [kernel.kallsyms]
              0.11%             106        0.14%          26                [native_sched_clock+0 -&gt; native_sched_clock+98]  [kernel.kallsyms]
              0.10%              97        0.53%          97            [trigger_load_balance+0 -&gt; trigger_load_balance+67]  [kernel.kallsyms]
              0.09%              85        0.46%          85             [get-dynamic-info.h:102 -&gt; get-dynamic-info.h:111]         ld-2.27.so
  ...
              0.00%           92.7K        0.02%           4                           [triad_loop.c:64 -&gt; triad_loop.c:65]         triad_loop

The hottest block '[triad_loop.c:64 -&gt; triad_loop.c:65]' is not at
the top of output.

After:

  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles                                           [Program Block Range]      Shared Object
  # ...............  ..............  ...........  ..........  ..............................................................  .................
  #
             94.35%           92.7K        0.02%           4                            [triad_loop.c:64 -&gt; triad_loop.c:65]         triad_loop
              0.81%             793        4.32%         793                            [setup-vdso.h:34 -&gt; setup-vdso.h:40]         ld-2.27.so
              0.49%             480        0.87%         160                     [native_write_msr+0 -&gt; native_write_msr+16]  [kernel.kallsyms]
              0.48%             476        0.52%          95                       [native_read_msr+0 -&gt; native_read_msr+29]  [kernel.kallsyms]
              0.31%             303        1.65%         303                               [nmi_restore+0 -&gt; nmi_restore+37]  [kernel.kallsyms]
              0.26%             255        1.39%         255       [nohz_balance_exit_idle+75 -&gt; nohz_balance_exit_idle+162]  [kernel.kallsyms]
              0.24%             234        1.28%         234                        [end_repeat_nmi+67 -&gt; end_repeat_nmi+83]  [kernel.kallsyms]
              0.23%             227        1.24%         227             [__irqentry_text_end+96 -&gt; __irqentry_text_end+126]  [kernel.kallsyms]
              0.20%             194        1.06%         194              [native_set_debugreg+52 -&gt; native_set_debugreg+56]  [kernel.kallsyms]
              0.11%             106        0.14%          26                 [native_sched_clock+0 -&gt; native_sched_clock+98]  [kernel.kallsyms]
              0.10%              97        0.53%          97             [trigger_load_balance+0 -&gt; trigger_load_balance+67]  [kernel.kallsyms]
              0.09%              85        0.46%          85              [get-dynamic-info.h:102 -&gt; get-dynamic-info.h:111]         ld-2.27.so
              0.08%              82        0.06%          11  [intel_pmu_drain_pebs_nhm+580 -&gt; intel_pmu_drain_pebs_nhm+627]  [kernel.kallsyms]
              0.08%              77        0.42%          77                  [lru_add_drain_cpu+0 -&gt; lru_add_drain_cpu+133]  [kernel.kallsyms]
              0.08%              74        0.10%          18                [handle_pmi_common+271 -&gt; handle_pmi_common+310]  [kernel.kallsyms]
              0.08%              74        0.40%          74              [get-dynamic-info.h:131 -&gt; get-dynamic-info.h:157]         ld-2.27.so
              0.07%              69        0.09%          17  [intel_pmu_drain_pebs_nhm+432 -&gt; intel_pmu_drain_pebs_nhm+468]  [kernel.kallsyms]

Now the hottest block is reported at the top of output.

Fixes: b65a7d372b1a55db ("perf hist: Support block formats with compare/sort/display")
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Reviewed-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210407024452.29988-1-yao.jin@linux.intel.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>
When '--total-cycles' is specified, it supports sorting for all blocks
by 'Sampled Cycles%'. This is useful to concentrate on the globally
hottest blocks.

'Sampled Cycles%' - block sampled cycles aggregation / total sampled cycles

But in current code, it doesn't use the cycles aggregation. Part of
'cycles' counting is possibly dropped for some overlap jumps. But for
identifying the hot block, we always need the full cycles.

  # perf record -b ./triad_loop
  # perf report --total-cycles --stdio

Before:

  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles                                          [Program Block Range]      Shared Object
  # ...............  ..............  ...........  ..........  .............................................................  .................
  #
              0.81%             793        4.32%         793                           [setup-vdso.h:34 -&gt; setup-vdso.h:40]         ld-2.27.so
              0.49%             480        0.87%         160                    [native_write_msr+0 -&gt; native_write_msr+16]  [kernel.kallsyms]
              0.48%             476        0.52%          95                      [native_read_msr+0 -&gt; native_read_msr+29]  [kernel.kallsyms]
              0.31%             303        1.65%         303                              [nmi_restore+0 -&gt; nmi_restore+37]  [kernel.kallsyms]
              0.26%             255        1.39%         255      [nohz_balance_exit_idle+75 -&gt; nohz_balance_exit_idle+162]  [kernel.kallsyms]
              0.24%             234        1.28%         234                       [end_repeat_nmi+67 -&gt; end_repeat_nmi+83]  [kernel.kallsyms]
              0.23%             227        1.24%         227            [__irqentry_text_end+96 -&gt; __irqentry_text_end+126]  [kernel.kallsyms]
              0.20%             194        1.06%         194             [native_set_debugreg+52 -&gt; native_set_debugreg+56]  [kernel.kallsyms]
              0.11%             106        0.14%          26                [native_sched_clock+0 -&gt; native_sched_clock+98]  [kernel.kallsyms]
              0.10%              97        0.53%          97            [trigger_load_balance+0 -&gt; trigger_load_balance+67]  [kernel.kallsyms]
              0.09%              85        0.46%          85             [get-dynamic-info.h:102 -&gt; get-dynamic-info.h:111]         ld-2.27.so
  ...
              0.00%           92.7K        0.02%           4                           [triad_loop.c:64 -&gt; triad_loop.c:65]         triad_loop

The hottest block '[triad_loop.c:64 -&gt; triad_loop.c:65]' is not at
the top of output.

After:

  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles                                           [Program Block Range]      Shared Object
  # ...............  ..............  ...........  ..........  ..............................................................  .................
  #
             94.35%           92.7K        0.02%           4                            [triad_loop.c:64 -&gt; triad_loop.c:65]         triad_loop
              0.81%             793        4.32%         793                            [setup-vdso.h:34 -&gt; setup-vdso.h:40]         ld-2.27.so
              0.49%             480        0.87%         160                     [native_write_msr+0 -&gt; native_write_msr+16]  [kernel.kallsyms]
              0.48%             476        0.52%          95                       [native_read_msr+0 -&gt; native_read_msr+29]  [kernel.kallsyms]
              0.31%             303        1.65%         303                               [nmi_restore+0 -&gt; nmi_restore+37]  [kernel.kallsyms]
              0.26%             255        1.39%         255       [nohz_balance_exit_idle+75 -&gt; nohz_balance_exit_idle+162]  [kernel.kallsyms]
              0.24%             234        1.28%         234                        [end_repeat_nmi+67 -&gt; end_repeat_nmi+83]  [kernel.kallsyms]
              0.23%             227        1.24%         227             [__irqentry_text_end+96 -&gt; __irqentry_text_end+126]  [kernel.kallsyms]
              0.20%             194        1.06%         194              [native_set_debugreg+52 -&gt; native_set_debugreg+56]  [kernel.kallsyms]
              0.11%             106        0.14%          26                 [native_sched_clock+0 -&gt; native_sched_clock+98]  [kernel.kallsyms]
              0.10%              97        0.53%          97             [trigger_load_balance+0 -&gt; trigger_load_balance+67]  [kernel.kallsyms]
              0.09%              85        0.46%          85              [get-dynamic-info.h:102 -&gt; get-dynamic-info.h:111]         ld-2.27.so
              0.08%              82        0.06%          11  [intel_pmu_drain_pebs_nhm+580 -&gt; intel_pmu_drain_pebs_nhm+627]  [kernel.kallsyms]
              0.08%              77        0.42%          77                  [lru_add_drain_cpu+0 -&gt; lru_add_drain_cpu+133]  [kernel.kallsyms]
              0.08%              74        0.10%          18                [handle_pmi_common+271 -&gt; handle_pmi_common+310]  [kernel.kallsyms]
              0.08%              74        0.40%          74              [get-dynamic-info.h:131 -&gt; get-dynamic-info.h:157]         ld-2.27.so
              0.07%              69        0.09%          17  [intel_pmu_drain_pebs_nhm+432 -&gt; intel_pmu_drain_pebs_nhm+468]  [kernel.kallsyms]

Now the hottest block is reported at the top of output.

Fixes: b65a7d372b1a55db ("perf hist: Support block formats with compare/sort/display")
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Reviewed-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210407024452.29988-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf record: Fix memory leak in vDSO found using ASAN</title>
<updated>2021-03-24T13:38:56+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2021-03-15T04:56:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=41d585411311abf187e5f09042978fe7073a9375'/>
<id>41d585411311abf187e5f09042978fe7073a9375</id>
<content type='text'>
I got several memory leak reports from Asan with a simple command.  It
was because VDSO is not released due to the refcount.  Like in
__dsos_addnew_id(), it should put the refcount after adding to the list.

  $ perf record true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.030 MB perf.data (10 samples) ]

  =================================================================
  ==692599==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 439 byte(s) in 1 object(s) allocated from:
    #0 0x7fea52341037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
    #1 0x559bce4aa8ee in dso__new_id util/dso.c:1256
    #2 0x559bce59245a in __machine__addnew_vdso util/vdso.c:132
    #3 0x559bce59245a in machine__findnew_vdso util/vdso.c:347
    #4 0x559bce50826c in map__new util/map.c:175
    #5 0x559bce503c92 in machine__process_mmap2_event util/machine.c:1787
    #6 0x559bce512f6b in machines__deliver_event util/session.c:1481
    #7 0x559bce515107 in perf_session__deliver_event util/session.c:1551
    #8 0x559bce51d4d2 in do_flush util/ordered-events.c:244
    #9 0x559bce51d4d2 in __ordered_events__flush util/ordered-events.c:323
    #10 0x559bce519bea in __perf_session__process_events util/session.c:2268
    #11 0x559bce519bea in perf_session__process_events util/session.c:2297
    #12 0x559bce2e7a52 in process_buildids /home/namhyung/project/linux/tools/perf/builtin-record.c:1017
    #13 0x559bce2e7a52 in record__finish_output /home/namhyung/project/linux/tools/perf/builtin-record.c:1234
    #14 0x559bce2ed4f6 in __cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2026
    #15 0x559bce2ed4f6 in cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2858
    #16 0x559bce422db4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:313
    #17 0x559bce2acac8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:365
    #18 0x559bce2acac8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:409
    #19 0x559bce2acac8 in main /home/namhyung/project/linux/tools/perf/perf.c:539
    #20 0x7fea51e76d09 in __libc_start_main ../csu/libc-start.c:308

  Indirect leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x7fea52341037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
    #1 0x559bce520907 in nsinfo__copy util/namespaces.c:169
    #2 0x559bce50821b in map__new util/map.c:168
    #3 0x559bce503c92 in machine__process_mmap2_event util/machine.c:1787
    #4 0x559bce512f6b in machines__deliver_event util/session.c:1481
    #5 0x559bce515107 in perf_session__deliver_event util/session.c:1551
    #6 0x559bce51d4d2 in do_flush util/ordered-events.c:244
    #7 0x559bce51d4d2 in __ordered_events__flush util/ordered-events.c:323
    #8 0x559bce519bea in __perf_session__process_events util/session.c:2268
    #9 0x559bce519bea in perf_session__process_events util/session.c:2297
    #10 0x559bce2e7a52 in process_buildids /home/namhyung/project/linux/tools/perf/builtin-record.c:1017
    #11 0x559bce2e7a52 in record__finish_output /home/namhyung/project/linux/tools/perf/builtin-record.c:1234
    #12 0x559bce2ed4f6 in __cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2026
    #13 0x559bce2ed4f6 in cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2858
    #14 0x559bce422db4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:313
    #15 0x559bce2acac8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:365
    #16 0x559bce2acac8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:409
    #17 0x559bce2acac8 in main /home/namhyung/project/linux/tools/perf/perf.c:539
    #18 0x7fea51e76d09 in __libc_start_main ../csu/libc-start.c:308

  SUMMARY: AddressSanitizer: 471 byte(s) leaked in 2 allocation(s).

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210315045641.700430-1-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>
I got several memory leak reports from Asan with a simple command.  It
was because VDSO is not released due to the refcount.  Like in
__dsos_addnew_id(), it should put the refcount after adding to the list.

  $ perf record true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.030 MB perf.data (10 samples) ]

  =================================================================
  ==692599==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 439 byte(s) in 1 object(s) allocated from:
    #0 0x7fea52341037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
    #1 0x559bce4aa8ee in dso__new_id util/dso.c:1256
    #2 0x559bce59245a in __machine__addnew_vdso util/vdso.c:132
    #3 0x559bce59245a in machine__findnew_vdso util/vdso.c:347
    #4 0x559bce50826c in map__new util/map.c:175
    #5 0x559bce503c92 in machine__process_mmap2_event util/machine.c:1787
    #6 0x559bce512f6b in machines__deliver_event util/session.c:1481
    #7 0x559bce515107 in perf_session__deliver_event util/session.c:1551
    #8 0x559bce51d4d2 in do_flush util/ordered-events.c:244
    #9 0x559bce51d4d2 in __ordered_events__flush util/ordered-events.c:323
    #10 0x559bce519bea in __perf_session__process_events util/session.c:2268
    #11 0x559bce519bea in perf_session__process_events util/session.c:2297
    #12 0x559bce2e7a52 in process_buildids /home/namhyung/project/linux/tools/perf/builtin-record.c:1017
    #13 0x559bce2e7a52 in record__finish_output /home/namhyung/project/linux/tools/perf/builtin-record.c:1234
    #14 0x559bce2ed4f6 in __cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2026
    #15 0x559bce2ed4f6 in cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2858
    #16 0x559bce422db4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:313
    #17 0x559bce2acac8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:365
    #18 0x559bce2acac8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:409
    #19 0x559bce2acac8 in main /home/namhyung/project/linux/tools/perf/perf.c:539
    #20 0x7fea51e76d09 in __libc_start_main ../csu/libc-start.c:308

  Indirect leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x7fea52341037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
    #1 0x559bce520907 in nsinfo__copy util/namespaces.c:169
    #2 0x559bce50821b in map__new util/map.c:168
    #3 0x559bce503c92 in machine__process_mmap2_event util/machine.c:1787
    #4 0x559bce512f6b in machines__deliver_event util/session.c:1481
    #5 0x559bce515107 in perf_session__deliver_event util/session.c:1551
    #6 0x559bce51d4d2 in do_flush util/ordered-events.c:244
    #7 0x559bce51d4d2 in __ordered_events__flush util/ordered-events.c:323
    #8 0x559bce519bea in __perf_session__process_events util/session.c:2268
    #9 0x559bce519bea in perf_session__process_events util/session.c:2297
    #10 0x559bce2e7a52 in process_buildids /home/namhyung/project/linux/tools/perf/builtin-record.c:1017
    #11 0x559bce2e7a52 in record__finish_output /home/namhyung/project/linux/tools/perf/builtin-record.c:1234
    #12 0x559bce2ed4f6 in __cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2026
    #13 0x559bce2ed4f6 in cmd_record /home/namhyung/project/linux/tools/perf/builtin-record.c:2858
    #14 0x559bce422db4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:313
    #15 0x559bce2acac8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:365
    #16 0x559bce2acac8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:409
    #17 0x559bce2acac8 in main /home/namhyung/project/linux/tools/perf/perf.c:539
    #18 0x7fea51e76d09 in __libc_start_main ../csu/libc-start.c:308

  SUMMARY: AddressSanitizer: 471 byte(s) leaked in 2 allocation(s).

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210315045641.700430-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Fix BPF support related crash with perf_event_paranoid=3 + kptr_restrict</title>
<updated>2021-03-16T13:01:44+00:00</updated>
<author>
<name>Jackie Liu</name>
<email>jackieliu2113@gmail.com</email>
</author>
<published>2021-03-16T01:24:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1a096ae46e21b73f83a581e617f76326c1de592d'/>
<id>1a096ae46e21b73f83a581e617f76326c1de592d</id>
<content type='text'>
After installing the libelf-dev package and compiling perf, if we have
kptr_restrict=2 and perf_event_paranoid=3 'perf top' will crash because
the value of /proc/kallsyms cannot be obtained, which leads to
info-&gt;jited_ksyms == NULL. In order to solve this problem, Add a
check before use.

Also plug some leaks on the error path.

Suggested-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Jackie Liu &lt;liuyun01@kylinos.cn&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: jackie liu &lt;liuyun01@kylinos.cn&gt;
Link: http://lore.kernel.org/lkml/20210316012453.1156-1-liuyun01@kylinos.cn
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>
After installing the libelf-dev package and compiling perf, if we have
kptr_restrict=2 and perf_event_paranoid=3 'perf top' will crash because
the value of /proc/kallsyms cannot be obtained, which leads to
info-&gt;jited_ksyms == NULL. In order to solve this problem, Add a
check before use.

Also plug some leaks on the error path.

Suggested-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Jackie Liu &lt;liuyun01@kylinos.cn&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: jackie liu &lt;liuyun01@kylinos.cn&gt;
Link: http://lore.kernel.org/lkml/20210316012453.1156-1-liuyun01@kylinos.cn
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf pmu: Validate raw event with sysfs exported format bits</title>
<updated>2021-03-15T13:12:02+00:00</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2021-03-10T05:11:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e40647762fb5881360874e08e03e972d58d63c42'/>
<id>e40647762fb5881360874e08e03e972d58d63c42</id>
<content type='text'>
A raw PMU event (eventsel+umask) in the form of rNNN is supported
by perf but lacks of checking for the validity of raw encoding.

For example, bit 16 and bit 17 are not valid on KBL but perf doesn't
report warning when encoding with these bits.

Before:

  # ./perf stat -e cpu/r031234/ -a -- sleep 1

   Performance counter stats for 'system wide':

                   0      cpu/r031234/

         1.003798924 seconds time elapsed

It may silently measure the wrong event!

The kernel supported bits have been exported through
/sys/devices/&lt;pmu&gt;/format/. Perf collects the information to
'struct perf_pmu_format' and links it to 'pmu-&gt;format' list.

The 'struct perf_pmu_format' has a bitmap which records the
valid bits for this format. For example,

  root@kbl-ppc:/sys/devices/cpu/format# cat umask
  config:8-15

The valid bits (bit8-bit15) are recorded in bitmap of format 'umask'.

We collect total valid bits of all formats, save to a local variable
'masks' and reverse it. Now '~masks' represents total invalid bits.

bits = config &amp; ~masks;

The set bits in 'bits' indicate the invalid bits used in config.
Finally we use bitmap_scnprintf to report the invalid bits.

Some architectures may not export supported bits through sysfs,
so if masks is 0, perf_pmu__warn_invalid_config directly returns.

After:

Single event without name:

  # ./perf stat -e cpu/r031234/ -a -- sleep 1
  WARNING: event 'N/A' not valid (bits 16-17 of config '31234' not supported by kernel)!

   Performance counter stats for 'system wide':

                   0      cpu/r031234/

         1.001597373 seconds time elapsed

Multiple events with names:

  # ./perf stat -e cpu/rf01234,name=aaa/,cpu/r031234,name=bbb/ -a -- sleep 1
  WARNING: event 'aaa' not valid (bits 20,22 of config 'f01234' not supported by kernel)!
  WARNING: event 'bbb' not valid (bits 16-17 of config '31234' not supported by kernel)!

   Performance counter stats for 'system wide':

                   0      aaa
                   0      bbb

         1.001573787 seconds time elapsed

Warnings are reported for invalid bits.

Co-developed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210310051138.12154-1-yao.jin@linux.intel.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>
A raw PMU event (eventsel+umask) in the form of rNNN is supported
by perf but lacks of checking for the validity of raw encoding.

For example, bit 16 and bit 17 are not valid on KBL but perf doesn't
report warning when encoding with these bits.

Before:

  # ./perf stat -e cpu/r031234/ -a -- sleep 1

   Performance counter stats for 'system wide':

                   0      cpu/r031234/

         1.003798924 seconds time elapsed

It may silently measure the wrong event!

The kernel supported bits have been exported through
/sys/devices/&lt;pmu&gt;/format/. Perf collects the information to
'struct perf_pmu_format' and links it to 'pmu-&gt;format' list.

The 'struct perf_pmu_format' has a bitmap which records the
valid bits for this format. For example,

  root@kbl-ppc:/sys/devices/cpu/format# cat umask
  config:8-15

The valid bits (bit8-bit15) are recorded in bitmap of format 'umask'.

We collect total valid bits of all formats, save to a local variable
'masks' and reverse it. Now '~masks' represents total invalid bits.

bits = config &amp; ~masks;

The set bits in 'bits' indicate the invalid bits used in config.
Finally we use bitmap_scnprintf to report the invalid bits.

Some architectures may not export supported bits through sysfs,
so if masks is 0, perf_pmu__warn_invalid_config directly returns.

After:

Single event without name:

  # ./perf stat -e cpu/r031234/ -a -- sleep 1
  WARNING: event 'N/A' not valid (bits 16-17 of config '31234' not supported by kernel)!

   Performance counter stats for 'system wide':

                   0      cpu/r031234/

         1.001597373 seconds time elapsed

Multiple events with names:

  # ./perf stat -e cpu/rf01234,name=aaa/,cpu/r031234,name=bbb/ -a -- sleep 1
  WARNING: event 'aaa' not valid (bits 20,22 of config 'f01234' not supported by kernel)!
  WARNING: event 'bbb' not valid (bits 16-17 of config '31234' not supported by kernel)!

   Performance counter stats for 'system wide':

                   0      aaa
                   0      bbb

         1.001573787 seconds time elapsed

Warnings are reported for invalid bits.

Co-developed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210310051138.12154-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf synthetic events: Avoid write of uninitialized memory when generating PERF_RECORD_MMAP* records</title>
<updated>2021-03-10T12:20:59+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2021-03-09T23:49:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2a76f6de07906f0bb5f2a13fb02845db1695cc29'/>
<id>2a76f6de07906f0bb5f2a13fb02845db1695cc29</id>
<content type='text'>
Account for alignment bytes in the zero-ing memset.

Fixes: 1a853e36871b533c ("perf record: Allow specifying a pid to record")
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&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;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: http://lore.kernel.org/lkml/20210309234945.419254-1-irogers@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>
Account for alignment bytes in the zero-ing memset.

Fixes: 1a853e36871b533c ("perf record: Allow specifying a pid to record")
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&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;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: http://lore.kernel.org/lkml/20210309234945.419254-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf synthetic-events: Fix uninitialized 'kernel_thread' variable</title>
<updated>2021-03-10T12:16:47+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2021-03-09T11:04:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c3d59cfde9cc1fa699eb6bf0d3ce4156354e3a98'/>
<id>c3d59cfde9cc1fa699eb6bf0d3ce4156354e3a98</id>
<content type='text'>
perf build fails on 5.12.0rc2 on s390 with this error message:

util/synthetic-events.c: In function
				‘__event__synthesize_thread.part.0.isra’:
util/synthetic-events.c:787:19: error: ‘kernel_thread’ may be
    used uninitialized in this function [-Werror=maybe-uninitialized]
    787 |   if (_pid == pid &amp;&amp; !kernel_thread) {
        |       ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~

The build succeeds using command 'make DEBUG=y'.

The variable kernel_thread is set by this function sequence:

__event__synthesize_thread()
|    defines bool kernel_thread; as local variable and calls
+--&gt; perf_event__prepare_comm(..., &amp;kernel_thread)
     +--&gt; perf_event__get_comm_ids(..., bool *kernel);
          On return of this function variable kernel is always
          set to true or false.

To prevent this compile error, assign variable kernel_thread
a value when it is defined.

Output after:

  [root@m35lp76 perf]# make  util/synthetic-events.o
  ....
   CC       util/synthetic-events.o
  [root@m35lp76 perf]#

Fixes: c1b907953b2cd9ff ("perf tools: Skip PERF_RECORD_MMAP event synthesis for kernel threads")
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&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/20210309110447.834292-1-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 build fails on 5.12.0rc2 on s390 with this error message:

util/synthetic-events.c: In function
				‘__event__synthesize_thread.part.0.isra’:
util/synthetic-events.c:787:19: error: ‘kernel_thread’ may be
    used uninitialized in this function [-Werror=maybe-uninitialized]
    787 |   if (_pid == pid &amp;&amp; !kernel_thread) {
        |       ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~

The build succeeds using command 'make DEBUG=y'.

The variable kernel_thread is set by this function sequence:

__event__synthesize_thread()
|    defines bool kernel_thread; as local variable and calls
+--&gt; perf_event__prepare_comm(..., &amp;kernel_thread)
     +--&gt; perf_event__get_comm_ids(..., bool *kernel);
          On return of this function variable kernel is always
          set to true or false.

To prevent this compile error, assign variable kernel_thread
a value when it is defined.

Output after:

  [root@m35lp76 perf]# make  util/synthetic-events.o
  ....
   CC       util/synthetic-events.o
  [root@m35lp76 perf]#

Fixes: c1b907953b2cd9ff ("perf tools: Skip PERF_RECORD_MMAP event synthesis for kernel threads")
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&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/20210309110447.834292-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
