99 lines
3.8 KiB
Diff
99 lines
3.8 KiB
Diff
From 736d13f5a840e28e2db51c749e9ef67a7099a277 Mon Sep 17 00:00:00 2001
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From: John Garry <john.garry@huawei.com>
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Date: Thu, 10 Jun 2021 22:32:59 +0800
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Subject: [PATCH 201/201] perf metricgroup: Fix find_evsel_group() event
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selector
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mainline inclusion
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from mainline-v5.13-rc7
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commit fc96ec4d5d4155c61cbafd49fb2dd403c899a9f4
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category: bugfix
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bugzilla: https://gitee.com/openeuler/kernel/issues/I8C0CX
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Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fc96ec4d5d4155c61cbafd49fb2dd403c899a9f4
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----------------------------------------------------------------------
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The following command segfaults on my x86 broadwell:
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$ ./perf stat -M frontend_bound,retiring,backend_bound,bad_speculation sleep 1
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WARNING: grouped events cpus do not match, disabling group:
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anon group { raw 0x10e }
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anon group { raw 0x10e }
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perf: util/evsel.c:1596: get_group_fd: Assertion `!(!leader->core.fd)' failed.
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Aborted (core dumped)
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The issue shows itself as a use-after-free in evlist__check_cpu_maps(),
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whereby the leader of an event selector (evsel) has been deleted (yet we
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still attempt to verify for an evsel).
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Fundamentally the problem comes from metricgroup__setup_events() ->
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find_evsel_group(), and has developed from the previous fix attempt in
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commit 9c880c24cb0d ("perf metricgroup: Fix for metrics containing
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duration_time").
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The problem now is that the logic in checking if an evsel is in the same
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group is subtly broken for the "cycles" event. For the "cycles" event,
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the pmu_name is NULL; however the logic in find_evsel_group() may set an
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event matched against "cycles" as used, when it should not be.
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This leads to a condition where an evsel is set, yet its leader is not.
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Fix the check for evsel pmu_name by not matching evsels when either has a
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NULL pmu_name.
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There is still a pre-existing metric issue whereby the ordering of the
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metrics may break the 'stat' function, as discussed at:
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https://lore.kernel.org/lkml/49c6fccb-b716-1bf0-18a6-cace1cdb66b9@huawei.com/
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Fixes: 9c880c24cb0d ("perf metricgroup: Fix for metrics containing duration_time")
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Signed-off-by: John Garry <john.garry@huawei.com>
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Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> # On a Thinkpad T450S
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Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Cc: Ian Rogers <irogers@google.com>
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Cc: Jiri Olsa <jolsa@redhat.com>
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Cc: Kajol Jain <kjain@linux.ibm.com>
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Cc: Mark Rutland <mark.rutland@arm.com>
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Cc: Namhyung Kim <namhyung@kernel.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Link: http://lore.kernel.org/lkml/1623335580-187317-2-git-send-email-john.garry@huawei.com
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Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Signed-off-by: hongrongxuan <hongrongxuan@huawei.com>
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Conflicts:
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tools/perf/util/metricgroup.c
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---
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tools/perf/util/metricgroup.c | 7 ++++---
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1 file changed, 4 insertions(+), 3 deletions(-)
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diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
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index 32c5919c9413..c6679f9cad9c 100644
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--- a/tools/perf/util/metricgroup.c
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+++ b/tools/perf/util/metricgroup.c
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@@ -167,10 +167,11 @@ static bool contains_event(struct perf_evsel **metric_events, int num_events,
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return false;
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}
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-static bool evsel_same_pmu(struct perf_evsel *ev1, struct perf_evsel *ev2)
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+static bool evsel_same_pmu_or_none(struct perf_evsel *ev1,
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+ struct perf_evsel *ev2)
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{
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if (!ev1->pmu_name || !ev2->pmu_name)
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- return false;
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+ return true;
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return !strcmp(ev1->pmu_name, ev2->pmu_name);
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}
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@@ -293,7 +294,7 @@ static struct perf_evsel *find_evsel_group(struct perf_evlist *perf_evlist,
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*/
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if (!has_constraint &&
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ev->leader != metric_events[i]->leader &&
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- evsel_same_pmu(ev->leader, metric_events[i]->leader))
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+ evsel_same_pmu_or_none(ev->leader, metric_events[i]->leader))
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break;
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if (!strcmp(metric_events[i]->name, ev->name)) {
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set_bit(ev->idx, evlist_used);
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--
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2.27.0
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