Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a0231628 authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
Browse files

blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" 



[ 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: default avatarChanghui Zhong <czhong@redhat.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231117023527.3188627-2-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent eac54659

block/blk-throttle.c

+2 −0
Original line number Diff line number Diff line
@@ -1391,6 +1391,7 @@ 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
@@ -1418,6 +1419,7 @@ 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