Commit 8074b26f authored Feb 24, 2011 by Miklos Szeredi Committed by Linus Torvalds Feb 24, 2011

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: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Linus 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) {

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