Commit d69cba5c authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

futex: Reorder sanity checks in futex_requeue() 



No point in allocating memory when the input parameters are bogus.
Validate all parameters before proceeding.

Suggested-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.581789253@linutronix.de
parent c18eaa3a

kernel/futex.c

+7 −7
Original line number Diff line number Diff line
@@ -1933,13 +1933,6 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, 
		if (uaddr1 == uaddr2)

			return -EINVAL;



		/*

		 * requeue_pi requires a pi_state, try to allocate it now

		 * without any locks in case it fails.

		 */

		if (refill_pi_state_cache())

			return -ENOMEM;



		/*

		 * futex_requeue() allows the caller to define the number

		 * of waiters to wake up via the @nr_wake argument. With
@@ -1963,6 +1956,13 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, 
		 */

		if (nr_wake != 1)

			return -EINVAL;



		/*

		 * requeue_pi requires a pi_state, try to allocate it now

		 * without any locks in case it fails.

		 */

		if (refill_pi_state_cache())

			return -ENOMEM;

	}



retry: