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Commit 647a20d5 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: do not reuse dm_blk_ioctl block_device input as local variable 



(Ab)using the @bdev passed to dm_blk_ioctl() opens the potential for
targets' .prepare_ioctl to fail if they go on to check the bdev for
!NULL.

Fixes: e56f81e0 ("dm: refactor ioctl handling")
Reported-by: default avatarJunichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 5bbbfdf6

drivers/md/dm.c

+3 −2
Original line number Diff line number Diff line
@@ -603,9 +603,10 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, 
{

	struct mapped_device *md = bdev->bd_disk->private_data;

	struct dm_target *tgt;

	struct block_device *tgt_bdev = NULL;

	int srcu_idx, r;



	r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);

	r = dm_get_live_table_for_ioctl(md, &tgt, &tgt_bdev, &mode, &srcu_idx);

	if (r < 0)

		return r;
@@ -620,7 +621,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, 
			goto out;

	}



	r =  __blkdev_driver_ioctl(bdev, mode, cmd, arg);

	r =  __blkdev_driver_ioctl(tgt_bdev, mode, cmd, arg);

out:

	dm_put_live_table(md, srcu_idx);

	return r;