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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05CA6C3DA7D for ; Wed, 28 Dec 2022 16:43:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234900AbiL1QnP (ORCPT ); Wed, 28 Dec 2022 11:43:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234991AbiL1Qmr (ORCPT ); Wed, 28 Dec 2022 11:42:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2CA319297 for ; Wed, 28 Dec 2022 08:37:06 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8D3E261582 for ; Wed, 28 Dec 2022 16:36:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E1EBC433EF; Wed, 28 Dec 2022 16:36:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245396; bh=JUAeLU86nUvk5bPoxhEtCwSImejOmLGxr2MFOlOWN1M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hUfhCW2T8ULqG0SVqIxJ6HQV44FeatC9s2QhEPdpMeDeD1WXptMmOGVn9l8XhfQCV A2GoB3jPEPLBmwiaXNgfYlrf0POOZ+qSjByOvk2AeUnfKEZ5fnOEubHdxK9Pwhh4BO 2BcJnVniKP3wpu8096iimWWV9jSb1zCnX5kptHdY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zqiang , "Joel Fernandes (Google)" , "Paul E. McKenney" , Sasha Levin Subject: [PATCH 6.0 0885/1073] rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Date: Wed, 28 Dec 2022 15:41:13 +0100 Message-Id: <20221228144352.066228933@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144328.162723588@linuxfoundation.org> References: <20221228144328.162723588@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Zqiang [ Upstream commit ceb1c8c9b8aa9199da46a0f29d2d5f08d9b44c15 ] Running rcutorture with non-zero fqs_duration module parameter in a kernel built with CONFIG_PREEMPTION=y results in the following splat: BUG: using __this_cpu_read() in preemptible [00000000] code: rcu_torture_fqs/398 caller is __this_cpu_preempt_check+0x13/0x20 CPU: 3 PID: 398 Comm: rcu_torture_fqs Not tainted 6.0.0-rc1-yoctodev-standard+ Call Trace: dump_stack_lvl+0x5b/0x86 dump_stack+0x10/0x16 check_preemption_disabled+0xe5/0xf0 __this_cpu_preempt_check+0x13/0x20 rcu_force_quiescent_state.part.0+0x1c/0x170 rcu_force_quiescent_state+0x1e/0x30 rcu_torture_fqs+0xca/0x160 ? rcu_torture_boost+0x430/0x430 kthread+0x192/0x1d0 ? kthread_complete_and_exit+0x30/0x30 ret_from_fork+0x22/0x30 The problem is that rcu_force_quiescent_state() uses __this_cpu_read() in preemptible code instead of the proper raw_cpu_read(). This commit therefore changes __this_cpu_read() to raw_cpu_read(). Signed-off-by: Zqiang Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 5b52727dcc1c..aedd43e1f21c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2415,7 +2415,7 @@ void rcu_force_quiescent_state(void) struct rcu_node *rnp_old = NULL; /* Funnel through hierarchy to reduce memory contention. */ - rnp = __this_cpu_read(rcu_data.mynode); + rnp = raw_cpu_read(rcu_data.mynode); for (; rnp != NULL; rnp = rnp->parent) { ret = (READ_ONCE(rcu_state.gp_flags) & RCU_GP_FLAG_FQS) || !raw_spin_trylock(&rnp->fqslock); -- 2.35.1