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 8595937874; Mon, 18 Dec 2023 14:13:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mO7GE+f9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DAE7C433C9; Mon, 18 Dec 2023 14:13:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702908828; bh=DOPJ2fjS5c+lhhhZDqbIENydPGc9YI0YCcH1H4csrtM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mO7GE+f9fOfzDxCrW5Z2VmKFPgA3gB7R5KN1ywPhgm8rmnK6PLWVjHY0gRNqI2bWp m1vpKwZKgA0EQ9j8ujv5EvIhrvGxyh8ETFxbHPvkNYXvyssO2/+5AnVMjaXxjv9dZ9 0qnhyjiPVtN5rHYRL6MTJ+rNvdpp94+Rrik+kDP0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Changhui Zhong , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 5.15 48/83] blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" Date: Mon, 18 Dec 2023 14:52:09 +0100 Message-ID: <20231218135051.858511420@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218135049.738602288@linuxfoundation.org> References: <20231218135049.738602288@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ 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 68cf8dbb4c67a..4da4b25b12f48 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1415,6 +1415,7 @@ 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 @@ -1442,6 +1443,7 @@ 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 -- 2.43.0