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Commit 8074b26f authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
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mm: fix refcounting in swapon 



Grab a reference to bdev before calling blkdev_get(), which expects
the refcount to be already incremented and either returns success or
decrements the refcount and returns an error.

The bug was introduced by e525fd89 (block: make blkdev_get/put()
handle exclusive access), which didn't take into account this behavior
of blkdev_get().

Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3c522ced

mm/swapfile.c

+1 −1
Original line number Diff line number Diff line
@@ -1940,7 +1940,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) 


	error = -EINVAL;

	if (S_ISBLK(inode->i_mode)) {

		bdev = I_BDEV(inode);

		bdev = bdgrab(I_BDEV(inode));

		error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,

				   sys_swapon);

		if (error < 0) {