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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-10-02 15:41:23 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-01 09:10:52 -0700
commit1d48ca6f38fa39298474708abebeffef4ef2cd2d (patch)
tree54af1961ab8589ebc3e6533c4083c0cdb2581db9
parent2cd21fa1b54efaf6b5912ef2833fa474fdcf92b7 (diff)
downloadlinux-linaro-stable-1d48ca6f38fa39298474708abebeffef4ef2cd2d.tar.gz
perf: Fix perf_cgroup_switch for sw-events
commit 95cf59ea72331d0093010543b8951bb43f262cac upstream. Jiri reported that he could trigger the WARN_ON_ONCE() in perf_cgroup_switch() using sw-events. This is because sw-events share a cpuctx with multiple PMUs. Use the ->unique_pmu pointer to limit the pmu iteration to unique cpuctx instances. Reported-and-Tested-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-so7wi2zf3jjzrwcutm2mkz0j@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/events/core.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f2c7f11247b7..8e82398c2843 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -368,6 +368,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
list_for_each_entry_rcu(pmu, &pmus, entry) {
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+ if (cpuctx->unique_pmu != pmu)
+ continue; /* ensure we process each cpuctx once */
/*
* perf_cgroup_events says at least one
@@ -391,9 +393,10 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
if (mode & PERF_CGROUP_SWIN) {
WARN_ON_ONCE(cpuctx->cgrp);
- /* set cgrp before ctxsw in to
- * allow event_filter_match() to not
- * have to pass task around
+ /*
+ * set cgrp before ctxsw in to allow
+ * event_filter_match() to not have to pass
+ * task around
*/
cpuctx->cgrp = perf_cgroup_from_task(task);
cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);