From 04dea5f93231204cc3ca0ab793ce76dbb10c86ba Mon Sep 17 00:00:00 2001
From: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Date: Thu, 5 May 2005 16:15:41 -0700
Subject: [PATCH] Kprobes: Oops! in unregister_kprobe()

kernel oops!  when unregister_kprobe() is called on a non-registered
kprobe.  This patch fixes the above problem by checking if the probe exists
before unregistering.

Signed-off-by: Prasanna S Panchamukhi <prasanna@in.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 1d5dd13..d8903e6 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -107,13 +107,17 @@ rm_kprobe:
 void unregister_kprobe(struct kprobe *p)
 {
 	unsigned long flags;
-	arch_remove_kprobe(p);
 	spin_lock_irqsave(&kprobe_lock, flags);
+	if (!get_kprobe(p->addr)) {
+		spin_unlock_irqrestore(&kprobe_lock, flags);
+		return;
+	}
 	*p->addr = p->opcode;
 	hlist_del(&p->hlist);
 	flush_icache_range((unsigned long) p->addr,
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 	spin_unlock_irqrestore(&kprobe_lock, flags);
+	arch_remove_kprobe(p);
 }
 
 static struct notifier_block kprobe_exceptions_nb = {
-- 
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