Re: [PATCH v2] block/blk-cgroup-rwstat: use data_race() for online test

[Tejun Heo]

On Mon, Aug 03, 2026 at 09:34:00PM +0800, Tao Cui wrote:
> From: Tao Cui <cuitao@xxxxxxxxxx>
> 
> blkg_rwstat_recursive_sum() reads pos_blkg->online without the queue
> lock that its doc comment requires, since blkcg_print_blkgs() stopped
> holding it in 56cc24f59c14.  Concurrent blkg_create/destroy flips
> ->online, tripping KCSAN.  The race is harmless (RCU-protected, stale
> online only causes minor stat noise).  Use data_race() to annotate
> the intentional lockless read.
> 
> Also update the stale doc comment that still requires the queue lock.
> 
> Reviewed-by: Yu Kuai <yukuai@xxxxxxx>
> Signed-off-by: Tao Cui <cuitao@xxxxxxxxxx>

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

-- 
tejun