| Message ID | 20220415035607.1836495-1-yukuai3@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND] blk-mq: fix possible creation failure for 'debugfs_dir' | expand |
On Fri, 15 Apr 2022 11:56:07 +0800, Yu Kuai wrote: > 'q->debugfs_dir' is created in blk_register_queue(), however, it's not > removed in blk_unregister_queue() and is delayed to blk_release_queue(). > Thus it's possible that del_gendisk() is done and blk_release_queue() > is not called yet, and in the mean time blk_register_queue() is called > for the new device with the same name. In this case, kernel will > compalin about creation failure for 'debugfs_dir' like following: > > [...] Applied, thanks! [1/1] blk-mq: fix possible creation failure for 'debugfs_dir' commit: a87c29e1a85e64b28445bb1e80505230bf2e3b4b Best regards,
On Fri, 2022-04-15 at 11:56 +0800, Yu Kuai wrote: > 'q->debugfs_dir' is created in blk_register_queue(), however, it's not > removed in blk_unregister_queue() and is delayed to blk_release_queue(). > Thus it's possible that del_gendisk() is done and blk_release_queue() > is not called yet, and in the mean time blk_register_queue() is called > for the new device with the same name. In this case, kernel will > compalin about creation failure for 'debugfs_dir' like following: > > debugfs: Directory 'nullb1' with parent 'block' already present! > > Fix the problem by moving forward the removal of 'debgfs_dir' to > blk_unregister_queue(). > > Signed-off-by: Yu Kuai <yukuai3@huawei.com> Looks like I'm late to the party, but for what its worth: Tested-by: Dan Williams <dan.j.williams@intel.com> Thanks!
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 88bd41d4cb59..15fc3f0786e3 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -779,11 +779,6 @@ static void blk_release_queue(struct kobject *kobj) if (queue_is_mq(q)) blk_mq_release(q); - blk_trace_shutdown(q); - mutex_lock(&q->debugfs_mutex); - debugfs_remove_recursive(q->debugfs_dir); - mutex_unlock(&q->debugfs_mutex); - if (queue_is_mq(q)) blk_mq_debugfs_unregister(q); @@ -951,5 +946,11 @@ void blk_unregister_queue(struct gendisk *disk) mutex_unlock(&q->sysfs_dir_lock); + blk_trace_shutdown(q); + mutex_lock(&q->debugfs_mutex); + blk_mq_debugfs_unregister_hctxs(q); + debugfs_remove_recursive(q->debugfs_dir); + mutex_unlock(&q->debugfs_mutex); + kobject_put(&disk_to_dev(disk)->kobj); }
'q->debugfs_dir' is created in blk_register_queue(), however, it's not removed in blk_unregister_queue() and is delayed to blk_release_queue(). Thus it's possible that del_gendisk() is done and blk_release_queue() is not called yet, and in the mean time blk_register_queue() is called for the new device with the same name. In this case, kernel will compalin about creation failure for 'debugfs_dir' like following: debugfs: Directory 'nullb1' with parent 'block' already present! Fix the problem by moving forward the removal of 'debgfs_dir' to blk_unregister_queue(). Signed-off-by: Yu Kuai <yukuai3@huawei.com> --- block/blk-sysfs.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)