futex: Check for NULL keys in match_futex

If userspace tries to perform a requeue_pi on a non-requeue_pi waiter, it will find the futex_q->requeue_pi_key to be NULL and OOPS. Check for NULL in match_futex() instead of doing explicit NULL pointer checks on all call sites. While match_futex(NULL, NULL) returning false is a little odd, it's still correct as we expect valid key references. Signed-off-by: Darren Hart <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ingo Molnar <[email protected]> CC: Eric Dumazet <[email protected]> CC: Dinakar Guniguntala <[email protected]> CC: John Stultz <[email protected]> Cc: [email protected] LKML-Reference: <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]>
ambv · Oct 14, 2009 · 2bc8720 · 2bc8720
1 parent d58e657
commit 2bc8720
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/futex.c b/kernel/futex.c
@@ -150,7 +150,8 @@ static struct futex_hash_bucket *hash_futex(union futex_key *key)
  */
 static inline int match_futex(union futex_key *key1, union futex_key *key2)
 {
-	return (key1->both.word == key2->both.word
+	return (key1 && key2
+		&& key1->both.word == key2->both.word
 		&& key1->both.ptr == key2->both.ptr
 		&& key1->both.offset == key2->both.offset);
 }