perf_events, trace: Fix probe unregister race

[mv-sheeva.git] / kernel / trace / trace_event_perf.c

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index cb6f365016e48f0c7f7848cbaebb39d45fb80c45..49c7abf2ba5c1fafce486293c6f95688e017c2ba 100644 (file)
--- 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));