Re: [PATCH v2 2/3] block: don't delete queue kobject before its children

Hannes Reinecke
2021-11-30T06:46:01Z

On 11/30/21 5:03 AM, Eric Biggers wrote:
> 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()")
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
> 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
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