Commit 2bc87203 authored Oct 14, 2009 by Darren Hart Committed by Thomas Gleixner Oct 14, 2009

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 <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dinakar Guniguntala <dino@in.ibm.com>
CC: John Stultz <johnstul@us.ibm.com>
Cc: stable@kernel.org
LKML-Reference: <4AD60687.10306@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent d58e6576

kernel/futex.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -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)		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.ptr == key2->both.ptr
	&& key1->both.offset == key2->both.offset);		&& key1->both.offset == key2->both.offset);
	}		}

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