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Commit 84fe3ca6 authored by Eric Biggers's avatar Eric Biggers Committed by Greg Kroah-Hartman
Browse files

block: don't delete queue kobject before its children 



[ Upstream commit 0f69288253e9fc7c495047720e523b9f1aba5712 ]

kobjects aren't supposed to be deleted before their child kobjects are
deleted.  Apparently this is usually benign; however, a WARN will be
triggered if one of the child kobjects has a named attribute group:

    sysfs group 'modes' not found for kobject 'crypto'
    WARNING: CPU: 0 PID: 1 at fs/sysfs/group.c:278 sysfs_remove_group+0x72/0x80
    ...
    Call Trace:
      sysfs_remove_groups+0x29/0x40 fs/sysfs/group.c:312
      __kobject_del+0x20/0x80 lib/kobject.c:611
      kobject_cleanup+0xa4/0x140 lib/kobject.c:696
      kobject_release lib/kobject.c:736 [inline]
      kref_put include/linux/kref.h:65 [inline]
      kobject_put+0x53/0x70 lib/kobject.c:753
      blk_crypto_sysfs_unregister+0x10/0x20 block/blk-crypto-sysfs.c:159
      blk_unregister_queue+0xb0/0x110 block/blk-sysfs.c:962
      del_gendisk+0x117/0x250 block/genhd.c:610

Fix this by moving the kobject_del() and the corresponding
kobject_uevent() to the correct place.

Fixes: 2c2086af ("block: Protect less code with sysfs_lock in blk_{un,}register_queue()")
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220124215938.2769-3-ebiggers@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent b68d1742

block/blk-sysfs.c

+5 −3
Original line number Diff line number Diff line
@@ -1060,15 +1060,17 @@ void blk_unregister_queue(struct gendisk *disk) 
	 */

	if (queue_is_mq(q))

		blk_mq_unregister_dev(disk_to_dev(disk), q);



	kobject_uevent(&q->kobj, KOBJ_REMOVE);

	kobject_del(&q->kobj);

	blk_trace_remove_sysfs(disk_to_dev(disk));



	mutex_lock(&q->sysfs_lock);

	if (q->elevator)

		elv_unregister_queue(q);

	mutex_unlock(&q->sysfs_lock);



	/* Now that we've deleted all child objects, we can delete the queue. */

	kobject_uevent(&q->kobj, KOBJ_REMOVE);

	kobject_del(&q->kobj);



	mutex_unlock(&q->sysfs_dir_lock);



	kobject_put(&disk_to_dev(disk)->kobj);