From: Christoph Hellwig hch@lst.de
mainline inclusion from mainline-v5.19-rc4 commit 99d055b4fd4bbb309c6cdb51a0d420669f777944 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9QJ1S CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The block debugfs files are created in blk_register_queue, which is called by add_disk and use a naming scheme based on the disk_name. After del_gendisk returns that name can be reused and thus we must not leave these debugfs files around, otherwise the kernel is unhappy and spews messages like:
Directory XXXXX with parent 'block' already present!
and the newly created devices will not have working debugfs files.
Move the unregistration to blk_unregister_queue instead (which matches the sysfs unregistration) to make sure the debugfs life time rules match those of the disk name.
As part of the move also make sure the whole debugfs unregistration is inside a single debugfs_mutex critical section.
Note that this breaks blktests block/002, which checks that the debugfs directory has not been removed while blktests is running, but that particular check should simply be removed from the test case.
Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20220614074827.458955-4-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Yu Kuai yukuai3@huawei.com --- block/blk-mq-debugfs.c | 8 -------- block/blk-mq-debugfs.h | 5 ----- block/blk-rq-qos.c | 4 ---- block/blk-sysfs.c | 16 ++++++++-------- 4 files changed, 8 insertions(+), 25 deletions(-)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index d8623d9a7b18..1e4a5ff73bd8 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -1009,14 +1009,6 @@ void blk_mq_debugfs_register_rqos(struct rq_qos *rqos) debugfs_create_files(rqos->debugfs_dir, rqos, rqos->ops->debugfs_attrs); }
-void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q) -{ - lockdep_assert_held(&q->debugfs_mutex); - - debugfs_remove_recursive(q->rqos_debugfs_dir); - q->rqos_debugfs_dir = NULL; -} - void blk_mq_debugfs_register_sched_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx) { diff --git a/block/blk-mq-debugfs.h b/block/blk-mq-debugfs.h index 891c3af6f611..f6898560b1f3 100644 --- a/block/blk-mq-debugfs.h +++ b/block/blk-mq-debugfs.h @@ -33,7 +33,6 @@ void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx);
void blk_mq_debugfs_register_rqos(struct rq_qos *rqos); void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos); -void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q); #else static inline void blk_mq_debugfs_register(struct request_queue *q) { @@ -80,10 +79,6 @@ static inline void blk_mq_debugfs_register_rqos(struct rq_qos *rqos) static inline void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos) { } - -static inline void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q) -{ -} #endif
#ifdef CONFIG_BLK_DEBUG_FS_ZONED diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index 249a6f05dd3b..d3a75693adbf 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -294,10 +294,6 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
void rq_qos_exit(struct request_queue *q) { - mutex_lock(&q->debugfs_mutex); - blk_mq_debugfs_unregister_queue_rqos(q); - mutex_unlock(&q->debugfs_mutex); - while (q->rq_qos) { struct rq_qos *rqos = q->rq_qos; q->rq_qos = rqos->next; diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 9e74668f98cc..ef38e165bb30 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -804,13 +804,6 @@ static void blk_release_queue(struct kobject *kobj) if (queue_is_mq(q)) blk_mq_release(q);
- mutex_lock(&q->debugfs_mutex); - blk_trace_shutdown(q); - debugfs_remove_recursive(q->debugfs_dir); - q->debugfs_dir = NULL; - q->sched_debugfs_dir = NULL; - mutex_unlock(&q->debugfs_mutex); - bioset_exit(&q->bio_split);
ida_simple_remove(&blk_queue_ida, q->id); @@ -973,8 +966,15 @@ void blk_unregister_queue(struct gendisk *disk) /* 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);
+ mutex_lock(&q->debugfs_mutex); + blk_trace_shutdown(q); + debugfs_remove_recursive(q->debugfs_dir); + q->debugfs_dir = NULL; + q->sched_debugfs_dir = NULL; + q->rqos_debugfs_dir = NULL; + mutex_unlock(&q->debugfs_mutex); + kobject_put(&disk_to_dev(disk)->kobj); }