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 11661C3DA6E for ; Sat, 17 Dec 2022 00:13:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230326AbiLQANS (ORCPT ); Fri, 16 Dec 2022 19:13:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230328AbiLQAMS (ORCPT ); Fri, 16 Dec 2022 19:12:18 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3BD9175AA; Fri, 16 Dec 2022 16:11:03 -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 ams.source.kernel.org (Postfix) with ESMTPS id 8953DB81E54; Sat, 17 Dec 2022 00:11:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D56EC433F0; Sat, 17 Dec 2022 00:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671235861; bh=xQSnoJUDlQ16f2L8CuWavgbI1e8D0xygcd69tyFUEqg=; h=From:To:Cc:Subject:Date:From; b=NFS2d06NkQsoRTY6muccCoLm66auuE79J3xo8YPivunWAjuJ4fwWSKRcxEs5yrvWU 9jEHgTWZ9457r6tXDueIVdivDGRs/i6N5alQ/eRyFrF/ADe1jaE0xXeD9ErIUYFKX6 OABwKbqKKNOrlqtn/YurkMzOA50dNbY26Xo3vRG4ZPKOn2Dwyhd5Hn1W2oItEIWJyN Jk8yhpjDHLrf003i2bTK3pSq5eNkm7RsAMtj2LOami0AFERHhaB4oNQ9nSnWIzszM2 FquPDSuHb5fGRE2jiq9mKIDdORg9/BRD7eR6EeYkDb4p2NBpZf1FwF5SfeKszV5Cgg gxrFut6s81fxw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zqiang , Joel Fernandes , "Paul E . McKenney" , Sasha Levin , frederic@kernel.org, quic_neeraju@quicinc.com, josh@joshtriplett.org, rcu@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 1/5] rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Date: Fri, 16 Dec 2022 19:10:53 -0500 Message-Id: <20221217001058.41426-1-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: rcu@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 b10d6bcea77d..3fe7c75c371b 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2650,7 +2650,7 @@ 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