From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9D8E42ABF; Tue, 28 Nov 2023 21:10:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lK9pGEHE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5570FC433AB; Tue, 28 Nov 2023 21:10:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701205804; bh=OMDZ9fqASL7nffEFfENMmnry5V0Pn1SmoWTR5bFEqlE=; h=From:To:Cc:Subject:Date:From; b=lK9pGEHEsC/ILGl0AHGYsGUmHDD0NBfZYEi0+f1k4hHVt4gUMsYo3UNhwFBTuIE8P qhldBZewe5b/P0jvsXyqDlZM0Lm9MiGlQYiIw1L/8LF2YkXGf40ntgY9AX2po7yhHQ lrvoKXP85wVdZeVDxzaw8O6MgyR6S1kUS/nNwXSIMiMUEjzRePcCNjI3T/Umchr4Ri WQbGHPiuT7Zmv07XFqCJVlHDCRAULqlG9aIL/vIvEXPFs10edHWJ9uLSe8hInf4A9r WGvAslYZVWF2SO7lelmYZULA4eMoMg/O006P7rRu3gIkBUMB5siu37c0IY5ErCl7dk Pis+3GTHd5B6Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ming Lei , Changhui Zhong , Jens Axboe , Sasha Levin , tj@kernel.org, josef@toxicpanda.com, cgroups@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 01/10] blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" Date: Tue, 28 Nov 2023 16:09:50 -0500 Message-ID: <20231128211001.877333-1-sashal@kernel.org> X-Mailer: git-send-email 2.42.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.300 Content-Transfer-Encoding: 8bit From: Ming Lei [ 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 Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20231117023527.3188627-2-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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