From 3771f0771154675d4a0ca780be2411f3cc357208 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 May 2010 12:31:09 +0200 Subject: perf_events, trace: Fix probe unregister race tracepoint_probe_unregister() does not synchronize against the probe callbacks, so do that explicitly. This properly serializes the callbacks and the free of the data used therein. Also, use this_cpu_ptr() where possible. Acked-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra LKML-Reference: <1274438476.1674.1702.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/trace/trace_event_perf.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace_event_perf.c') diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index cb6f365016e4..49c7abf2ba5c 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -116,7 +116,7 @@ int perf_trace_enable(struct perf_event *p_event) if (WARN_ON_ONCE(!list)) return -EINVAL; - list = per_cpu_ptr(list, smp_processor_id()); + list = this_cpu_ptr(list); hlist_add_head_rcu(&p_event->hlist_entry, list); return 0; @@ -142,6 +142,12 @@ void perf_trace_destroy(struct perf_event *p_event) tp_event->class->perf_probe, tp_event); + /* + * Ensure our callback won't be called anymore. See + * tracepoint_probe_unregister() and __DO_TRACE(). + */ + synchronize_sched(); + free_percpu(tp_event->perf_events); tp_event->perf_events = NULL; @@ -169,7 +175,7 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type, if (*rctxp < 0) return NULL; - raw_data = per_cpu_ptr(perf_trace_buf[*rctxp], smp_processor_id()); + raw_data = this_cpu_ptr(perf_trace_buf[*rctxp]); /* zero the dead bytes from align to not leak stack to user */ memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64)); -- cgit v1.2.2 From 2e97942fe57864588774f173cf4cd7bb68968b76 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 May 2010 16:22:33 +0200 Subject: perf_events, trace: Fix perf_trace_destroy(), mutex went missing Steve spotted I forgot to do the destroy under event_mutex. Reported-by: Steven Rostedt Signed-off-by: Peter Zijlstra LKML-Reference: <1274451913.1674.1707.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/trace/trace_event_perf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace_event_perf.c') diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 49c7abf2ba5c..e6f65887842c 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -132,8 +132,9 @@ void perf_trace_destroy(struct perf_event *p_event) struct ftrace_event_call *tp_event = p_event->tp_event; int i; + mutex_lock(&event_mutex); if (--tp_event->perf_refcount > 0) - return; + goto out; if (tp_event->class->reg) tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER); @@ -157,6 +158,8 @@ void perf_trace_destroy(struct perf_event *p_event) perf_trace_buf[i] = NULL; } } +out: + mutex_unlock(&event_mutex); } __kprobes void *perf_trace_buf_prepare(int size, unsigned short type, -- cgit v1.2.2