From: Eric Biggers ebiggers@google.com
[ 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: 2c2086afc2b8 ("block: Protect less code with sysfs_lock in blk_{un,}register_queue()") Reviewed-by: Hannes Reinecke hare@suse.de Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Eric Biggers ebiggers@google.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20220124215938.2769-3-ebiggers@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-sysfs.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 07494deb1a26..67836f212e2d 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -1002,9 +1002,6 @@ void blk_unregister_queue(struct gendisk *disk) */ if (q->mq_ops) 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); @@ -1015,6 +1012,11 @@ void blk_unregister_queue(struct gendisk *disk) if (q->request_fn || 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);