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 5B2A744C7B; Tue, 28 Nov 2023 21:09:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="auKkZZhF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12C00C433CD; Tue, 28 Nov 2023 21:09:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701205786; bh=gfTRgwpbepPJtGUiW85IAfzQ70VbVccuFpv2c4zqL2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=auKkZZhF7Z+Tqw/wgc6uJMJxD1r79Ah5zuidp5HwsqAnaIV0aBQ5WN22xW7MG2B1T qAAZjN6slRhkkpWBZe50J3vMyLo8shIIV6t8+vFyRUTHeiwEyKPYYo5bJp9hOneY5O agkhQqA+e7EFPo9eRbbBy3Yf8ELXupkl8+6KMz2xXdn3sb4GAcCUNqzMdNPvH+rV8k eKV07bBublXnWrY1xbEQRehq7EQlO1xWF6SjuUVW6l4RqQTjsm2qfiifwVWzFpXs/G a8VtlzQkYuemU1GHRjmTOQ4x9UAlz3HTYW6+rjnkLMRcB7ciNQm1CdyNusAbdvWVhY Z5RZ0LsFJ2sTw== 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 5.4 02/11] blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" Date: Tue, 28 Nov 2023 16:09:26 -0500 Message-ID: <20231128210941.877094-2-sashal@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231128210941.877094-1-sashal@kernel.org> References: <20231128210941.877094-1-sashal@kernel.org> 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 5.4.262 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 bd870f9ae4586..43444934b9850 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1374,6 +1374,7 @@ 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 @@ -1401,6 +1402,7 @@ 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