[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>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1d5dd1337bd1..d8903e60c99a 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 = {