From: Ming Lei <ming.lei@xxxxxxxxxx> [ Upstream commit 27b13e209ddca5979847a1b57890e0372c1edcee ] Inside blkg_for_each_descendant_pre(), both css_for_each_descendant_pre() and blkg_lookup() requires RCU read lock, and either cgroup_assert_mutex_or_rcu_locked() or rcu_read_lock_held() is called. Fix the warning by adding rcu read lock. Reported-by: Changhui Zhong <czhong@xxxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Link: https://lore.kernel.org/r/20231117023527.3188627-2-ming.lei@xxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- block/blk-throttle.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 853b1770df367..e58c03c504c10 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1383,6 +1383,7 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global) tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); + rcu_read_lock(); /* * Update has_rules[] flags for the updated tg's subtree. A tg is * considered to have rules if either the tg itself or any of its @@ -1410,6 +1411,7 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global) this_tg->latency_target = max(this_tg->latency_target, parent_tg->latency_target); } + rcu_read_unlock(); /* * We're already holding queue_lock and know @tg is valid. Let's -- 2.42.0
