From: John Garry john.garry@huawei.com

mainline inclusion from mainline-v5.11-rc5 commit 9c880c24cb0db49d6e62e6d882df1470b0be8038 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAXCB2 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 c2337d67199a1ea1 ("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: c2337d67199a1ea1 ("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@huaw... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: zhangqz 14294317+zhangqizhi3@user.noreply.gitee.com --- tools/perf/util/metricgroup.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c index 4c1321bfabd8..fc796b3694d2 100644 --- a/tools/perf/util/metricgroup.c +++ b/tools/perf/util/metricgroup.c @@ -162,6 +162,14 @@ static bool contains_event(struct evsel **metric_events, int num_events, return false; }

+static bool evsel_same_pmu(struct evsel *ev1, struct evsel *ev2) +{ + if (!ev1->pmu_name || !ev2->pmu_name) + return false; + + return !strcmp(ev1->pmu_name, ev2->pmu_name); +} + /** * Find a group of events in perf_evlist that correspond to those from a parsed * metric expression. Note, as find_evsel_group is called in the same order as @@ -280,8 +288,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, */ if (!has_constraint && ev->leader != metric_events[i]->leader && - !strcmp(ev->leader->pmu_name, - metric_events[i]->leader->pmu_name)) + evsel_same_pmu(ev->leader, metric_events[i]->leader)) break; if (!strcmp(metric_events[i]->name, ev->name)) { set_bit(ev->idx, evlist_used);