Commit 99d8690a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: fix error unwinding in device_add_disk 



One device_add is called disk->ev will be freed by disk_release, so we
should free it twice.  Fix this by allocating disk->ev after device_add
so that the extra local unwinding can be removed entirely.

Based on an earlier patch from Tetsuo Handa.

Reported-by: default avatarsyzbot <syzbot+28a66a9fbc621c939000@syzkaller.appspotmail.com>
Tested-by: default avatarsyzbot <syzbot+28a66a9fbc621c939000@syzkaller.appspotmail.com>
Fixes: 83cbce95 ("block: add error handling for device_add_disk / add_disk")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211221161851.788424-1-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 37e11c36

block/genhd.c

+6 −7
Original line number Diff line number Diff line
@@ -442,10 +442,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, 
		disk->first_minor = ret;

	}



	ret = disk_alloc_events(disk);

	if (ret)

		goto out_free_ext_minor;



	/* delay uevents, until we scanned partition table */

	dev_set_uevent_suppress(ddev, 1);
@@ -456,7 +452,12 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, 
		ddev->devt = MKDEV(disk->major, disk->first_minor);

	ret = device_add(ddev);

	if (ret)

		goto out_disk_release_events;

		goto out_free_ext_minor;



	ret = disk_alloc_events(disk);

	if (ret)

		goto out_device_del;



	if (!sysfs_deprecated) {

		ret = sysfs_create_link(block_depr, &ddev->kobj,

					kobject_name(&ddev->kobj));
@@ -538,8 +539,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, 
		sysfs_remove_link(block_depr, dev_name(ddev));

out_device_del:

	device_del(ddev);

out_disk_release_events:

	disk_release_events(disk);

out_free_ext_minor:

	if (disk->major == BLOCK_EXT_MAJOR)

		blk_free_ext_minor(disk->first_minor);