On Jun 22, 2023 / 16:42, Ming Lei wrote:
> When __blkcg_rstat_flush() is called from cgroup_rstat_flush*() code
> path, interrupt is always disabled.
>
> When we start to flush blkcg per-cpu stats list in __blkg_release()
> for avoiding to leak blkcg_gq's reference in commit 20cb1c2fb756
> ("blk-cgroup: Flush stats before releasing blkcg_gq"), local irq
> isn't disabled yet, then lockdep warning may be triggered because
> the dependent cgroup locks may be acquired from irq(soft irq) handler.
>
> Fix the issue by disabling local irq always.
>
> Fixes: 20cb1c2fb756 ("blk-cgroup: Flush stats before releasing blkcg_gq")
> Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
> Closes: https://lore.kernel.org/linux-block/pz2wzwnmn5tk3pwpskmjhli6g3qly7eoknilb26of376c7kwxy@qydzpvt6zpis/T/#u
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Jay Shin <jaeshin@xxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Waiman Long <longman@xxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Thanks Ming, I confirmed this avoids the WARN I reported. I also ran my test
sets and observed no regression. Looks good.
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
