linux-stable.git/tools/perf, branch v5.9.8

perf hists browser: Increase size of 'buf' in perf_evsel__hists_browse()

2020-11-10T11:39:01+00:00

commit 86449b12f626a65d2a2ecfada1e024488471f9e2 upstream.

Making perf with gcc-9.1.1 generates the following warning:

    CC       ui/browsers/hists.o
  ui/browsers/hists.c: In function 'perf_evsel__hists_browse':
  ui/browsers/hists.c:3078:61: error: '%d' directive output may be \
  truncated writing between 1 and 11 bytes into a region of size \
  between 2 and 12 [-Werror=format-truncation=]

   3078 |       "Max event group index to sort is %d (index from 0 to %d)",
        |                                                             ^~
  ui/browsers/hists.c:3078:7: note: directive argument in the range [-2147483648, 8]
   3078 |       "Max event group index to sort is %d (index from 0 to %d)",
        |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In file included from /usr/include/stdio.h:937,
                   from ui/browsers/hists.c:5:

IOW, the string in line 3078 might be too long for buf[] of 64 bytes.

Fix this by increasing the size of buf[] to 128.

Fixes: dbddf1747441  ("perf report/top TUI: Support hotkeys to let user select any event for sorting")
Signed-off-by: Song Liu 
Acked-by: Jiri Olsa 
Cc: Jin Yao 
Cc: stable@vger.kernel.org # v5.7+
Link: http://lore.kernel.org/lkml/20201030235431.534417-1-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf python scripting: Fix printable strings in python3 scripts

2020-11-05T10:51:47+00:00

commit 6fcd5ddc3b1467b3586972ef785d0d926ae4cdf4 upstream.

Hagen reported broken strings in python3 tracepoint scripts:

  make PYTHON=python3
  perf record -e sched:sched_switch -a -- sleep 5
  perf script --gen-script py
  perf script -s ./perf-script.py

  [..]
  sched__sched_switch      7 563231.759525792        0 swapper   prev_comm=bytearray(b'swapper/7\x00\x00\x00\x00\x00\x00\x00'), prev_pid=0, prev_prio=120, prev_state=, next_comm=bytearray(b'mutex-thread-co\x00'),

The problem is in the is_printable_array function that does not take the
zero byte into account and claim such string as not printable, so the
code will create byte array instead of string.

Committer testing:

After this fix:

sched__sched_switch 3 484522.497072626  1158680 kworker/3:0-eve  prev_comm=kworker/3:0, prev_pid=1158680, prev_prio=120, prev_state=I, next_comm=swapper/3, next_pid=0, next_prio=120
Sample: {addr=0, cpu=3, datasrc=84410401, datasrc_decode=N/A|SNP N/A|TLB N/A|LCK N/A, ip=18446744071841817196, period=1, phys_addr=0, pid=1158680, tid=1158680, time=484522497072626, transaction=0, values=[(0, 0)], weight=0}

sched__sched_switch 4 484522.497085610  1225814 perf             prev_comm=perf, prev_pid=1225814, prev_prio=120, prev_state=, next_comm=migration/4, next_pid=30, next_prio=0
Sample: {addr=0, cpu=4, datasrc=84410401, datasrc_decode=N/A|SNP N/A|TLB N/A|LCK N/A, ip=18446744071841817196, period=1, phys_addr=0, pid=1225814, tid=1225814, time=484522497085610, transaction=0, values=[(0, 0)], weight=0}

Fixes: 249de6e07458 ("perf script python: Fix string vs byte array resolving")
Signed-off-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Hagen Paul Pfeifer 
Cc: Alexander Shishkin 
Cc: Mark Rutland 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200928201135.3633850-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf vendor events amd: Add L2 Prefetch events for zen1

2020-11-05T10:51:47+00:00

commit 60d804521ec4cd01217a96f33cd1bb29e295333d upstream.

Later revisions of PPRs that post-date the original Family 17h events
submission patch add these events.

Specifically, they were not in this 2017 revision of the F17h PPR:

Processor Programming Reference (PPR) for AMD Family 17h Model 01h, Revision B1 Processors Rev 1.14 - April 15, 2017

But e.g., are included in this 2019 version of the PPR:

Processor Programming Reference (PPR) for AMD Family 17h Model 18h, Revision B1 Processors Rev. 3.14 - Sep 26, 2019

Fixes: 98c07a8f74f8 ("perf vendor events amd: perf PMU events for AMD Family 17h")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Kim Phillips 
Reviewed-by: Ian Rogers 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Borislav Petkov 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Jon Grimm 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Martin Jambor 
Cc: Martin Liška 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: stable@vger.kernel.org
Cc: Stephane Eranian 
Cc: Vijay Thakkar 
Cc: William Cohen 
Cc: Yunfeng Ye 
Link: http://lore.kernel.org/lkml/20200901220944.277505-1-kim.phillips@amd.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-04T17:09:05+00:00

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream.

In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.

Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:

  On Fri, May 1, 2020 at 11:28 AM Linus Torvalds  wrote:
  >
  > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams  wrote:
  > >
  > > However now I see that copy_user_generic() works for the wrong reason.
  > > It works because the exception on the source address due to poison
  > > looks no different than a write fault on the user address to the
  > > caller, it's still just a short copy. So it makes copy_to_user() work
  > > for the wrong reason relative to the name.
  >
  > Right.
  >
  > And it won't work that way on other architectures. On x86, we have a
  > generic function that can take faults on either side, and we use it
  > for both cases (and for the "in_user" case too), but that's an
  > artifact of the architecture oddity.
  >
  > In fact, it's probably wrong even on x86 - because it can hide bugs -
  > but writing those things is painful enough that everybody prefers
  > having just one function.

Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().

Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.

One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.

 [ bp: Massage a bit. ]

Signed-off-by: Dan Williams 
Signed-off-by: Borislav Petkov 
Reviewed-by: Tony Luck 
Acked-by: Michael Ellerman 
Cc: 
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman

Revert "x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()"

2020-11-04T17:08:28+00:00

This reverts commit a85748ed9eb70108f9605558f2754ca94ee91401 which is
commit ec6347bb43395cb92126788a1a5b25302543f815 upstream.

We had a mistake when merging a later patch in this series due to some
file movements, so revert this change for now, as we will add it back in
a later commit.

Signed-off-by: Greg Kroah-Hartman

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-01T11:47:03+00:00

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream.

In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.

Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:

  On Fri, May 1, 2020 at 11:28 AM Linus Torvalds  wrote:
  >
  > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams  wrote:
  > >
  > > However now I see that copy_user_generic() works for the wrong reason.
  > > It works because the exception on the source address due to poison
  > > looks no different than a write fault on the user address to the
  > > caller, it's still just a short copy. So it makes copy_to_user() work
  > > for the wrong reason relative to the name.
  >
  > Right.
  >
  > And it won't work that way on other architectures. On x86, we have a
  > generic function that can take faults on either side, and we use it
  > for both cases (and for the "in_user" case too), but that's an
  > artifact of the architecture oddity.
  >
  > In fact, it's probably wrong even on x86 - because it can hide bugs -
  > but writing those things is painful enough that everybody prefers
  > having just one function.

Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().

Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.

One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.

 [ bp: Massage a bit. ]

Signed-off-by: Dan Williams 
Signed-off-by: Borislav Petkov 
Reviewed-by: Tony Luck 
Acked-by: Michael Ellerman 
Cc: 
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman

perf trace: Fix off by ones in memset() after realloc() in arches using libaudit

2020-10-29T09:11:50+00:00

[ Upstream commit f3013f7ed465479e60c1ab1921a5718fc541cc3b ]

'perf trace ls' started crashing after commit d21cb73a9025 on
!HAVE_SYSCALL_TABLE_SUPPORT configs (armv7l here) like this:

  0  strlen () at ../sysdeps/arm/armv6t2/strlen.S:126
  1  0xb6800780 in __vfprintf_internal (s=0xbeff9908, s@entry=0xbeff9900, format=0xa27160 "]: %s()", ap=..., mode_flags=) at vfprintf-internal.c:1688
  ...
  5  0x0056ecdc in fprintf (__fmt=0xa27160 "]: %s()", __stream=) at /usr/include/bits/stdio2.h:100
  6  trace__sys_exit (trace=trace@entry=0xbeffc710, evsel=evsel@entry=0xd968d0, event=, sample=sample@entry=0xbeffc3e8) at builtin-trace.c:2475
  7  0x00566d40 in trace__handle_event (sample=0xbeffc3e8, event=, trace=0xbeffc710) at builtin-trace.c:3122
  ...
  15 main (argc=2, argv=0xbefff6e8) at perf.c:538

It is because memset in trace__read_syscall_info zeroes wrong memory:

1) when initializing for the first time, it does not reset the last id.

2) in other cases, it resets the last id of previous buffer.

ad 1) it causes the crash above as sc->name used in the fprintf above
      contains garbage.

ad 2) it sets nonexistent from true back to false for id 11 here. Not
      sure, what the consequences are.

So fix it by introducing a special case for the initial initialization
and do the right +1 in both cases.

Fixes: d21cb73a9025 ("perf trace: Grow the syscall table as needed when using libaudit")
Signed-off-by: Jiri Slaby 
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20201001093419.15761-1-jslaby@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf stat: Skip duration_time in setup_system_wide

2020-10-29T09:11:45+00:00

[ Upstream commit 002a3d690f95804bdef6b70b26154103518e13d9 ]

Some metrics (such as DRAM_BW_Use) consists of uncore events and
duration_time. For uncore events, counter->core.system_wide is true. But
for duration_time, counter->core.system_wide is false so
target.system_wide is set to false.

Then 'enable_on_exec' is set in perf_event_attr of uncore event.  Kernel
will return error when trying to open the uncore event.

This patch skips the duration_time in setup_system_wide then
target.system_wide will be set to true for the evlist of uncore events +
duration_time.

Before (tested on skylake desktop):

  # perf stat -M DRAM_BW_Use -- sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
  /bin/dmesg | grep -i perf may provide additional information.

After:

  # perf stat -M DRAM_BW_Use -- sleep 1

   Performance counter stats for 'system wide':

                169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
             40,427      arb/event=0x81,umask=0x1/
      1,000,902,197 ns   duration_time

        1.000902197 seconds time elapsed

Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")
Signed-off-by: Jin Yao 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20200922015004.30114-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf metricgroup: Fix uncore metric expressions

2020-10-29T09:11:44+00:00

[ Upstream commit dcc81be0fc4e66943041e6e19a5faf8f8704a27e ]

A metric like DRAM_BW_Use has on SkylakeX events uncore_imc/cas_count_read/
and uncore_imc/case_count_write/.

These events open 6 events per socket with pmu names of
uncore_imc_[0-5].

The current metric setup code in find_evsel_group assumes one ID will
map to 1 event to be recorded in metric_events.

For events with multiple matches, the first event is recorded in
metric_events (avoiding matching >1 event with the same name) and the
evlist_used updated so that duplicate events aren't removed when the
evlist has unused events removed.

Before this change:

  $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1

   Performance counter stats for 'system wide':

               41.14 MiB  uncore_imc/cas_count_read/
       1,002,614,251 ns   duration_time

         1.002614251 seconds time elapsed

After this change:

  $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1

   Performance counter stats for 'system wide':

              157.47 MiB  uncore_imc/cas_count_read/ #     0.00 DRAM_BW_Use
              126.97 MiB  uncore_imc/cas_count_write/
       1,003,019,728 ns   duration_time

Erroneous duplication introduced in:
commit 2440689d62e9 ("perf metricgroup: Remove duped metric group events").

Fixes: ded80bda8bc9 ("perf expr: Migrate expr ids table to a hashmap").
Reported-by: Jin Yao 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexei Starovoitov 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Athira Jajeev 
Cc: Daniel Borkmann 
Cc: Jiri Olsa 
Cc: John Fastabend 
Cc: KP Singh 
Cc: Mark Rutland 
Cc: Martin KaFai Lau 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Song Liu 
Cc: Stephane Eranian 
Cc: Yonghong Song 
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200917201807.4090224-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf intel-pt: Fix "context_switch event has no tid" error

2020-10-29T09:11:44+00:00

[ Upstream commit 7d537a8d2e76bc4fc71e34545ceaa463ac2cd928 ]

A context_switch event can have no tid because pids can be detached from
a task while the task is still running (in do_exit()). Note this won't
happen with per-task contexts because then tracing stops at
perf_event_exit_task()

If a task with no tid gets preempted, or a dying task gets preempted and
its parent releases it, when it subsequently gets switched back in,
Intel PT will not be able to determine what task is running and prints
an error "context_switch event has no tid". However, it is not really an
error because the task is in kernel space and the decoder can continue
to decode successfully. Fix by changing the error to be only a logged
message, and make allowance for tid == -1.

Example:

  Using 5.9-rc4 with Preemptible Kernel (Low-Latency Desktop) e.g.
  $ uname -r
  5.9.0-rc4
  $ grep PREEMPT .config
  # CONFIG_PREEMPT_NONE is not set
  # CONFIG_PREEMPT_VOLUNTARY is not set
  CONFIG_PREEMPT=y
  CONFIG_PREEMPT_COUNT=y
  CONFIG_PREEMPTION=y
  CONFIG_PREEMPT_RCU=y
  CONFIG_PREEMPT_NOTIFIERS=y
  CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
  CONFIG_DEBUG_PREEMPT=y
  # CONFIG_PREEMPT_TRACER is not set
  # CONFIG_PREEMPTIRQ_DELAY_TEST is not set

Before:

  $ cat forkit.c

  #include 
  #include 
  #include 

  int main()
  {
          pid_t child;
          int status = 0;

          child = fork();
          if (child == 0)
                  return 123;
          wait(&status);
          return 0;
  }

  $ gcc -o forkit forkit.c
  $ sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k &
  [1] 11016
  $ taskset 2 ./forkit
  $ sudo pkill perf
  $ [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 17.262 MB perf.data ]

  [1]+  Terminated              sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k
  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
  context_switch event has no tid
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)

After:

  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)
            forkit 11019 [001] 66663.271688752: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:    -1/-1
               :-1    -1 [001] 66663.271692086: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
                :-1    -1 [001] 66663.271707466:          1 instructions:k:  ffffffffb18eb096 update_load_avg+0x306 ([kernel.kallsyms])

Fixes: 86c2786994bd7c ("perf intel-pt: Add support for PERF_RECORD_SWITCH")
Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Yu-cheng Yu 
Link: http://lore.kernel.org/lkml/20200909084923.9096-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin