[PATCH 2/5] perf: Support disable() after stop() on software events
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From: Frederic Weisbecker on 12 Jun 2010 03:40 If we call perf_event_stop() on a software event and then the disable() pmu callback on them after that, we'll call twice hlist_del_rcu() on the same hlist node and then bring a crash by dereferencing LIST_POISON2. Just use hlist_del_init_rcu() instead to fix this problem. This preparates for new context exclusions. Signed-off-by: Frederic Weisbecker <fweisbec(a)gmail.com> Cc: Ingo Molnar <mingo(a)elte.hu> Cc: Peter Zijlstra <a.p.zijlstra(a)chello.nl> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Paul Mackerras <paulus(a)samba.org> Cc: Stephane Eranian <eranian(a)google.com> Cc: Cyrill Gorcunov <gorcunov(a)gmail.com> Cc: Zhang Yanmin <yanmin_zhang(a)linux.intel.com> Cc: Steven Rostedt <rostedt(a)goodmis.org> --- kernel/perf_event.c | 2 +- kernel/trace/trace_event_perf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 95a56ed..c5f2306 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4292,7 +4292,7 @@ static int perf_swevent_enable(struct perf_event *event) static void perf_swevent_disable(struct perf_event *event) { - hlist_del_rcu(&event->hlist_entry); + hlist_del_init_rcu(&event->hlist_entry); } static void perf_swevent_void(struct perf_event *event) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 4799d70..7bc1f26 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -122,7 +122,7 @@ int perf_trace_enable(struct perf_event *p_event) void perf_trace_disable(struct perf_event *p_event) { - hlist_del_rcu(&p_event->hlist_entry); + hlist_del_init_rcu(&p_event->hlist_entry); } void perf_trace_destroy(struct perf_event *p_event) -- 1.6.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |