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

[Ananth N Mavinakayanahalli <ananth@in.ibm.com>]

From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

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>

---
 kernel/kprobes.c |    3 +++
 1 files changed, 3 insertions(+)

Index: linux-2.6.17-rc1/kernel/kprobes.c
===================================================================
--- linux-2.6.17-rc1.orig/kernel/kprobes.c
+++ linux-2.6.17-rc1/kernel/kprobes.c
@@ -585,6 +585,9 @@ int __kprobes register_kretprobe(struct 
 	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) {