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Commit a99e4e41 authored by Vernon Mauery's avatar Vernon Mauery Committed by Linus Torvalds
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[PATCH] pi-futex: fix mm_struct memory leak 



lock_queue was getting called essentially twice in a row and was
continually incrementing the mm_count ref count, thus causing a memory
leak.

Dinakar Guniguntala provided a proper fix for the problem that simply grabs
the spinlock for the hash bucket queue rather than calling lock_queue.

The second time we do a queue_lock in futex_lock_pi, we really only need to
take the hash bucket lock.

Signed-off-by: default avatarDinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: default avatarVernon Mauery <vernux@us.ibm.com>
Acked-by: default avatarPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9262e914

kernel/futex.c

+1 −1
Original line number Diff line number Diff line
@@ -1208,7 +1208,7 @@ static int do_futex_lock_pi(u32 __user *uaddr, int detect, int trylock, 
	}



	down_read(&curr->mm->mmap_sem);

	hb = queue_lock(&q, -1, NULL);

	spin_lock(q.lock_ptr);



	/*

	 * Got the lock. We might not be the anticipated owner if we