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 6850BC46467 for ; Sat, 17 Dec 2022 00:12:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229880AbiLQAMe (ORCPT ); Fri, 16 Dec 2022 19:12:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbiLQALr (ORCPT ); Fri, 16 Dec 2022 19:11:47 -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 C21FFE47; Fri, 16 Dec 2022 16:10:44 -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 77211B81E55; Sat, 17 Dec 2022 00:10:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EC0AC433EF; Sat, 17 Dec 2022 00:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671235842; bh=8EsqfBJhnpIecq5KIgt0aYEKapSpV/WLVB1jLuGwtIA=; h=From:To:Cc:Subject:Date:From; b=J9vzjex4uq0g8nvXNZWbNphSlQJhr6hd0zkBjgClKIO6RCSyVhjlA9zmyj5+zVGWu 75b3APOJP6NeLiJRfGK6GW2IlZbDZQ+xnINEkoTOgZ0TgW/Ou5CY/uMr6FaW1r49hD H4BhXs0BbAt97IAnpYYuBQ/FYNj7KSyDvi72TdwYX9RN8DACnrUsqLvy0Ykq+60vSC 4zcidgqnx510BuXjKMC+5FYmXFr+k7nkWf62IoUMcyUBWNFBDRgssjnD2wfXQOqURz E1OSmhdtcAdYdtR2EUYW6QUqmsZS2VllH4KkV3mYwLFUIVD/gTUS0Svi5shcz6C6HV Z2NB/SAjEHnKg== 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 5.15 1/5] rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Date: Fri, 16 Dec 2022 19:10:34 -0500 Message-Id: <20221217001038.41355-1-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 63f7ce228cc3..cf101da389b0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2674,7 +2674,7 @@ 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