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

Jens Axboe <[email protected]> Mon, 03 Aug 2026 20:17:07 -0600

Newsgroups	org.kernel.vger.linux-block,org.kernel.vger.cgroups,org.kernel.vger.linux-kernel
Message-ID	<178580982757.518281.5036620938854770535.b4-ty@b4>

On Mon, 03 Aug 2026 21:34:00 +0800, Tao Cui wrote:
> 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.
> 
> [...]

Applied, thanks!

[1/1] block/blk-cgroup-rwstat: use data_race() for online test
      (no commit info)

Best regards,
-- 
Jens Axboe