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authorPeter Zijlstra <peterz@infradead.org>2015-02-25 15:56:04 +0100
committerIngo Molnar <mingo@kernel.org>2015-03-27 09:49:45 +0100
commitccd41c86ad4d464d0ed4e48d80759ff85c2115b0 (patch)
treeb53b1e7507761a9144f900eff6f97cd4bb6d15c5 /kernel
parent9332d250b4b4f67c633894b311e022e3cf943bd5 (diff)
perf: Fix racy group access
While looking at some fuzzer output I noticed that we do not hold any locks on leader->ctx and therefore the sibling_list iteration is unsafe. Acquire the relevant ctx->mutex before calling into the pmu specific code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Link: http://lkml.kernel.org/r/20150225151639.GL5029@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b01dfb602db1..bb1a7c36e794 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7036,12 +7036,23 @@ EXPORT_SYMBOL_GPL(perf_pmu_unregister);
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
+ struct perf_event_context *ctx = NULL;
int ret;
if (!try_module_get(pmu->module))
return -ENODEV;
+
+ if (event->group_leader != event) {
+ ctx = perf_event_ctx_lock(event->group_leader);
+ BUG_ON(!ctx);
+ }
+
event->pmu = pmu;
ret = pmu->event_init(event);
+
+ if (ctx)
+ perf_event_ctx_unlock(event->group_leader, ctx);
+
if (ret)
module_put(pmu->module);