Commit 49379e6d authored Nov 29, 2018 by Dan Carpenter Committed by Jens Axboe Nov 29, 2018

ataflop: fix error handling in atari_floppy_init()



Smatch complains that there is an off by one if the allocation fails in:

	DMABuffer = atari_stram_alloc(BUFFER_SIZE+512, "ataflop");

In that situation, "i" would be point to one element beyond the end of
the unit[] array.

There is a second bug because the error handling calls
blk_mq_free_tag_set(&unit[i].tag_set); regardless of whether
"disk->queue" is NULL or non-NULL.  So if blk_mq_init_sq_queue() fails,
then that means unit[i].tag_set->tags is NULL and it leads to an Oops.

It's easiest to call put_disk() before the goto to clean up the partial
iteration.  Then the earlier unit[] elements are fully allocated so we
can remove the checks whether "disk->queue" is NULL and the code is
simpler.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 65cd1d13

drivers/block/ataflop.c

+6 −10

Original line number	Diff line number	Diff line
		@@ -1982,6 +1982,7 @@ static int __init atari_floppy_init (void)
		&ataflop_mq_ops, 2,
		BLK_MQ_F_SHOULD_MERGE);
		if (IS_ERR(unit[i].disk->queue)) {
		put_disk(unit[i].disk);
		ret = PTR_ERR(unit[i].disk->queue);
		unit[i].disk->queue = NULL;
		goto err;
		@@ -2033,18 +2034,13 @@ static int __init atari_floppy_init (void)
		return 0;

		err:
		do {
		while (--i >= 0) {
		struct gendisk *disk = unit[i].disk;

		if (disk) {
		if (disk->queue) {
		blk_cleanup_queue(disk->queue);
		disk->queue = NULL;
		}
		blk_mq_free_tag_set(&unit[i].tag_set);
		put_disk(unit[i].disk);
		}
		} while (i--);

		unregister_blkdev(FLOPPY_MAJOR, "fd");
		return ret;

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