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 B5DBBC54EBE for ; Mon, 16 Jan 2023 16:38:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233604AbjAPQi3 (ORCPT ); Mon, 16 Jan 2023 11:38:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233603AbjAPQhd (ORCPT ); Mon, 16 Jan 2023 11:37:33 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4771B32E68 for ; Mon, 16 Jan 2023 08:26:42 -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 D89CC61049 for ; Mon, 16 Jan 2023 16:26:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA1C9C433EF; Mon, 16 Jan 2023 16:26:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673886401; bh=psW9D7HuHQR8IbgKxb7fKgnTBW7O+7/ybDF+u7UdMx0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EZNxAvwwJfsnKRDu7F8JmA6IOz9K12KyZgB4kXQCC45z7P0sWIdIhm8q+y2yVQ29T ++fwCQQpop68Nxw54OJATz2WDX0bO0BbJFynGfm0bD/4UJ4GIzdk/D29XpSdlQbSao NKow8pxdbEAdmf7MkhePJisafaTacACiAb3/20/g= 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 5.4 386/658] rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Date: Mon, 16 Jan 2023 16:47:54 +0100 Message-Id: <20230116154927.218408039@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@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 5797cf2909b0..615283404d9d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2317,7 +2317,7 @@ 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