6.8-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
[ Upstream commit 8b8ace080319a866f5dfe9da8e665ae51d971c54 ]
Multiple gendisk instances can allocated/added for single request queue in case of disk rebind. blkg may still stay in q->blkg_list when calling blkcg_init_disk() for rebind, then q->blkg_list becomes corrupted.
Fix the list corruption issue by:
- add blkg_init_queue() to initialize q->blkg_list & q->blkcg_mutex only - move calling blkg_init_queue() into blk_alloc_queue()
The list corruption should be started since commit f1c006f1c685 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()") which delays removing blkg from q->blkg_list into blkg_free_workfn().
Fixes: f1c006f1c685 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()") Fixes: 1059699f87eb ("block: move blkcg initialization/destroy into disk allocation/release handler") Cc: Yu Kuai yukuai3@huawei.com Cc: Tejun Heo tj@kernel.org Signed-off-by: Ming Lei ming.lei@redhat.com Reviewed-by: Yu Kuai yukuai3@huawei.com Link: https://lore.kernel.org/r/20240407125910.4053377-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-cgroup.c | 9 ++++++--- block/blk-cgroup.h | 2 ++ block/blk-core.c | 2 ++ 3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index ff93c385ba5af..4529122e0cbdb 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1409,6 +1409,12 @@ static int blkcg_css_online(struct cgroup_subsys_state *css) return 0; }
+void blkg_init_queue(struct request_queue *q) +{ + INIT_LIST_HEAD(&q->blkg_list); + mutex_init(&q->blkcg_mutex); +} + int blkcg_init_disk(struct gendisk *disk) { struct request_queue *q = disk->queue; @@ -1416,9 +1422,6 @@ int blkcg_init_disk(struct gendisk *disk) bool preloaded; int ret;
- INIT_LIST_HEAD(&q->blkg_list); - mutex_init(&q->blkcg_mutex); - new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); if (!new_blkg) return -ENOMEM; diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index b927a4a0ad030..5b0bdc268ade9 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -188,6 +188,7 @@ struct blkcg_policy { extern struct blkcg blkcg_root; extern bool blkcg_debug_stats;
+void blkg_init_queue(struct request_queue *q); int blkcg_init_disk(struct gendisk *disk); void blkcg_exit_disk(struct gendisk *disk);
@@ -481,6 +482,7 @@ struct blkcg { };
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } +static inline void blkg_init_queue(struct request_queue *q) { } static inline int blkcg_init_disk(struct gendisk *disk) { return 0; } static inline void blkcg_exit_disk(struct gendisk *disk) { } static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; } diff --git a/block/blk-core.c b/block/blk-core.c index de771093b5268..99d684085719d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -431,6 +431,8 @@ struct request_queue *blk_alloc_queue(int node_id) init_waitqueue_head(&q->mq_freeze_wq); mutex_init(&q->mq_freeze_lock);
+ blkg_init_queue(q); + /* * Init percpu_ref in atomic mode so that it's faster to shutdown. * See blk_register_queue() for details.