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authorSong Liu <songliubraving@fb.com>2020-01-22 11:50:27 -0800
committerIngo Molnar <mingo@kernel.org>2020-01-28 21:20:19 +0100
commit07c5972951f088094776038006a0592a46d14bbc (patch)
tree520cbc9d27be3122880b5ddc43226e1350a08eec /kernel/events
parent003461559ef7a9bd0239bae35a22ad8924d6e9ad (diff)
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perf/cgroups: Install cgroup events to correct cpuctx
cgroup events are always installed in the cpuctx. However, when it is not installed via IPI, list_update_cgroup_event() adds it to cpuctx of current CPU, which triggers list corruption: [] list_add double add: new=ffff888ff7cf0db0, prev=ffff888ff7ce82f0, next=ffff888ff7cf0db0. To reproduce this, we can simply run: # perf stat -e cs -a & # perf stat -e cs -G anycgroup Fix this by installing it to cpuctx that contains event->ctx, and the proper cgrp_cpuctx_list. Fixes: db0503e4f675 ("perf/core: Optimize perf_install_in_event()") Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200122195027.2112449-1-songliubraving@fb.com
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2d9aeba1f3e2..fdb7f7ef380c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -951,9 +951,9 @@ list_update_cgroup_event(struct perf_event *event,
/*
* Because cgroup events are always per-cpu events,
- * this will always be called from the right CPU.
+ * @ctx == &cpuctx->ctx.
*/
- cpuctx = __get_cpu_context(ctx);
+ cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
/*
* Since setting cpuctx->cgrp is conditional on the current @cgrp
@@ -979,7 +979,8 @@ list_update_cgroup_event(struct perf_event *event,
cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
if (add)
- list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
+ list_add(cpuctx_entry,
+ per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
else
list_del(cpuctx_entry);
}