tracepoints: fix disable

Impact: fix race

Set the probe array pointer to NULL when the tracepoint is disabled.
The probe array point not being NULL could generate a race condition
where the reader would dereference a freed pointer.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index e96590f17de16903115c0a21e17a585d9cb72bda..47a7303d6cd9813ab583ebc79a05d09d47f536d0 100644 (file)
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -262,6 +262,7 @@ static void set_tracepoint(struct tracepoint_entry **entry,
 static void disable_tracepoint(struct tracepoint *elem)
 {
        elem->state = 0;
+       rcu_assign_pointer(elem->funcs, NULL);
 }
 
 /**