From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C09FC76195 for ; Mon, 15 Jul 2019 14:22:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1116A21537 for ; Mon, 15 Jul 2019 14:22:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200531; bh=raCm2z9IR6RzYY5VMxy8o2cFZlPyoTrU7xWbKHrzAn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a+vz3LE4jEnAj+ApWxhXszUmB2W86UjiC+V3ttQ2A2iIWRDBW/Crxv5kQeFJLtsRv lJMjv3hGSSZiycTcyUmmkBf6ly8UN68pxhz1+bEPt+dhRyE+MLL+/dzjU7TsICqwi3 lVeXqc2dWCIOpoZGMRK/neR5Lic65nIiaOVkFRhk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389841AbfGOOWE (ORCPT ); Mon, 15 Jul 2019 10:22:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:48668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390545AbfGOOVy (ORCPT ); Mon, 15 Jul 2019 10:21:54 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 978AA2184C; Mon, 15 Jul 2019 14:21:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200514; bh=raCm2z9IR6RzYY5VMxy8o2cFZlPyoTrU7xWbKHrzAn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gi+oZm8JA8IhKUZ8U6lO2JoPBqduAld6zpOrd1zcda/AjwNNV9zYdzOL/JeGHmnaM BtFDNhi/Q8YQbiRW83KQZjFOF+n+QsZhwm1doQlEp7Z68WaWoO4hdp+qHjNRT3BA74 JG6Pshwd6AmB0o6SbIiwC2CteRUG7ZDbMYb6K/gk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Waiman Long , "Paul E . McKenney" , Sasha Levin , rcu@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 067/158] rcu: Force inlining of rcu_read_lock() Date: Mon, 15 Jul 2019 10:16:38 -0400 Message-Id: <20190715141809.8445-67-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715141809.8445-1-sashal@kernel.org> References: <20190715141809.8445-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Waiman Long [ Upstream commit 6da9f775175e516fc7229ceaa9b54f8f56aa7924 ] When debugging options are turned on, the rcu_read_lock() function might not be inlined. This results in lockdep's print_lock() function printing "rcu_read_lock+0x0/0x70" instead of rcu_read_lock()'s caller. For example: [ 10.579995] ============================= [ 10.584033] WARNING: suspicious RCU usage [ 10.588074] 4.18.0.memcg_v2+ #1 Not tainted [ 10.593162] ----------------------------- [ 10.597203] include/linux/rcupdate.h:281 Illegal context switch in RCU read-side critical section! [ 10.606220] [ 10.606220] other info that might help us debug this: [ 10.606220] [ 10.614280] [ 10.614280] rcu_scheduler_active = 2, debug_locks = 1 [ 10.620853] 3 locks held by systemd/1: [ 10.624632] #0: (____ptrval____) (&type->i_mutex_dir_key#5){.+.+}, at: lookup_slow+0x42/0x70 [ 10.633232] #1: (____ptrval____) (rcu_read_lock){....}, at: rcu_read_lock+0x0/0x70 [ 10.640954] #2: (____ptrval____) (rcu_read_lock){....}, at: rcu_read_lock+0x0/0x70 These "rcu_read_lock+0x0/0x70" strings are not providing any useful information. This commit therefore forces inlining of the rcu_read_lock() function so that rcu_read_lock()'s caller is instead shown. Signed-off-by: Waiman Long Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- include/linux/rcupdate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e102c5bccbb9..68cbe111420b 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -620,7 +620,7 @@ static inline void rcu_preempt_sleep_check(void) { } * read-side critical sections may be preempted and they may also block, but * only when acquiring spinlocks that are subject to priority inheritance. */ -static inline void rcu_read_lock(void) +static __always_inline void rcu_read_lock(void) { __rcu_read_lock(); __acquire(RCU); -- 2.20.1