From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Fri, 14 Nov 2008 22:47:42 +0000 (-0500)
Subject: tracepoints: fix disable
X-Git-Tag: v2.6.30-rc1~2^2~265^3~9
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=de0baf9ad661ac630a45a50ea1717cc4f4b33ace

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 e96590f..47a7303 100644
--- 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);
 }
 
 /**