From: Eric Biggers <ebiggers@kernel.org>
To: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-mmc@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bart Van Assche <bvanassche@acm.org>,
Hannes Reinecke <hare@suse.de>
Subject: [PATCH v4 2/3] block: don't delete queue kobject before its children
Date: Mon, 24 Jan 2022 13:59:37 -0800 [thread overview]
Message-ID: <20220124215938.2769-3-ebiggers@kernel.org> (raw)
In-Reply-To: <20220124215938.2769-1-ebiggers@kernel.org>
From: Eric Biggers <ebiggers@google.com>
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>
---
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 a02b42ad9a6e0..66deaa9f3bc97 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -954,15 +954,17 @@ 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);
elv_unregister_queue(q);
disk_unregister_independent_access_ranges(disk);
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);
--
2.34.1
next prev parent reply other threads:[~2022-01-24 23:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 21:59 [PATCH v4 0/3] block: show crypto capabilities in sysfs Eric Biggers
2022-01-24 21:59 ` [PATCH v4 1/3] block: simplify calling convention of elv_unregister_queue() Eric Biggers
2022-01-25 7:25 ` Christoph Hellwig
2022-01-24 21:59 ` Eric Biggers [this message]
2022-01-25 7:26 ` [PATCH v4 2/3] block: don't delete queue kobject before its children Christoph Hellwig
2022-01-24 21:59 ` [PATCH v4 3/3] blk-crypto: show crypto capabilities in sysfs Eric Biggers
2022-02-21 2:23 ` [PATCH v4 0/3] block: " Eric Biggers
2022-02-28 8:11 ` Eric Biggers
2022-02-28 13:40 ` Jens Axboe
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