Commit-ID: ccd41c86ad4d464d0ed4e48d80759ff85c2115b0 Gitweb: http://git.kernel.org/tip/ccd41c86ad4d464d0ed4e48d80759ff85c2115b0 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Wed, 25 Feb 2015 15:56:04 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 27 Mar 2015 09:49:45 +0100
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) <pet...@infradead.org> Cc: Vince Weaver <vincent.wea...@maine.edu> Cc: Jiri Olsa <jo...@redhat.com> Cc: Sasha Levin <sasha.le...@oracle.com> Link: http://lkml.kernel.org/r/20150225151639.gl5...@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index b01dfb6..bb1a7c3 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
