[lkml]   [2022]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 5.10 147/599] block: dont delete queue kobject before its children
From: Eric Biggers <>

[ 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 <>
Reviewed-by: Greg Kroah-Hartman <>
Reviewed-by: Bart Van Assche <>
Signed-off-by: Eric Biggers <>
Reviewed-by: Christoph Hellwig <>
Signed-off-by: Jens Axboe <>
Signed-off-by: Sasha Levin <>
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 b513f1683af0..8c5816364dd1 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -958,15 +958,17 @@ 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);

if (q->elevator)
+ /* Now that we've deleted all child objects, we can delete the queue. */
+ kobject_uevent(&q->kobj, KOBJ_REMOVE);
+ kobject_del(&q->kobj);


 \ /
  Last update: 2022-04-05 22:43    [W:1.231 / U:1.484 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site