On 11/30/21 5:03 AM, Eric Biggers wrote:

From: Eric Biggers <redacted>

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()")
Signed-off-by: Eric Biggers <redacted>
---
  block/blk-sysfs.c | 8 +++++---
  1 file changed, 5 insertions(+), 3 deletions(-)

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer