Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 2/5] perf: Support disable() after stop() on software events | Date | Thu, 10 Jun 2010 05:49:17 +0200 |
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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@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Zhang Yanmin <yanmin_zhang@linux.intel.com> Cc: Steven Rostedt <rostedt@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 5c004f7..2d818bc 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4291,7 +4291,7 @@ 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
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