[PATCH] kprobes: NULL out non-relevant fields in struct kretprobe

In cases where a struct kretprobe's *_handler fields are non-NULL, it is
possible to cause a system crash, due to the possibility of calls ending up
in zombie functions.  Documentation clearly states that unused *_handlers
should be set to NULL, but kprobe users sometimes fail to do so.

Fix it by setting the non-relevant fields of the struct kretprobe to NULL.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1156eb0..1fbf466 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -585,6 +585,9 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
        int i;
 
        rp->kp.pre_handler = pre_handler_kretprobe;
+       rp->kp.post_handler = NULL;
+       rp->kp.fault_handler = NULL;
+       rp->kp.break_handler = NULL;
 
        /* Pre-allocate memory for max kretprobe instances */
        if (rp->maxactive <= 0) {