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futex: Reorder sanity checks in futex_requeue()

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

Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.581789253@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-08-15 23:29:15 +02:00 committed by Ingo Molnar
parent c18eaa3aca
commit d69cba5c71
1 changed files with 7 additions and 7 deletions
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14
kernel/futex.c
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@ -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: