Metrics containing duration_time cause a segfault:
$ perf stat -v -M L1D_Cache_Fill_BW sleep 1
Using CPUID GenuineIntel-6-3D-4
metric expr 64 * l1d.replacement / 1000000000 / duration_time for L1D_Cache_Fill_BW
found event duration_time
found event l1d.replacement
adding {l1d.replacement}:W,duration_time
l1d.replacement -> cpu/umask=0x1,(null)=0x1e8483,event=0x51/
Segmentation fault
$
In commit c2337d6719 ("perf metricgroup: Fix metrics using aliases
covering multiple PMUs"), the logic in find_evsel_group() when iter'ing
events was changed to not only select events in same group, but also for
aliased PMUs.
Checking whether events were for aliased PMUs was done by comparing the
event PMU name. This was not safe for duration_time event, which has no
associated PMU (and no PMU name), so fix by checking if the event PMU name
is set also.
Committer testing:
Reproduced the bug, then, on a:
$ grep -m1 ^'model name' /proc/cpuinfo
model name : Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
$
We now get:
$ perf stat -M L1D_Cache_Fill_BW sleep 1
Performance counter stats for 'sleep 1':
4,141 l1d.replacement:u
1,001,285,107 ns duration_time:u
1.001285107 seconds time elapsed
0.000000000 seconds user
0.001119000 seconds sys
$
Detais from -v:
Using CPUID GenuineIntel-6-8E-A
metric expr 64 * l1d.replacement / 1000000000 / duration_time for L1D_Cache_Fill_BW
found event duration_time
found event l1d.replacement
adding {l1d.replacement}:W,duration_time
l1d.replacement -> cpu/(null)=0x1e8483,umask=0x1,event=0x51/
Control descriptor is not initialized
Warning:
kernel.perf_event_paranoid=2, trying to fall back to excluding kernel and hypervisor samples
Warning:
kernel.perf_event_paranoid=2, trying to fall back to excluding kernel and hypervisor samples
l1d.replacement:u: 4592 612201 612201
duration_time:u: 1001478621 1001478621 1001478621
Fixes: c2337d6719 ("perf metricgroup: Fix metrics using aliases covering multiple PMUs")
Reported-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linuxarm@openeuler.org
Link: https://lore.kernel.org/r/1611159518-226883-1-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
9c880c24cb