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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 9EE95C388F7 for ; Mon, 9 Nov 2020 13:15:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 52580216C4 for ; Mon, 9 Nov 2020 13:15:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927714; bh=fGjK7gRmILnSKAEFXyryQyXVvF2+PkK+LZc9osEOy+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Rzy2zaohRat1S86uaUQleoFvn5144JjszT8TEyXS0VzWoQ1/mUtA0fa6Q8v76hB5p RoRrSje/utmEDegAcThDkOQTxVs5Um9lqFuECmZxFAhHJNt1qpZn+5u+bGfvAWVwI8 4a5nipNGKYlWR88iD57Y8YK0S1K291KXz1nDvePk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732866AbgKINPM (ORCPT ); Mon, 9 Nov 2020 08:15:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:41780 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733277AbgKINPG (ORCPT ); Mon, 9 Nov 2020 08:15:06 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 731D320663; Mon, 9 Nov 2020 13:15:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927706; bh=fGjK7gRmILnSKAEFXyryQyXVvF2+PkK+LZc9osEOy+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YujlHXGtCledNgteNtcqSE1f/m36h/mix/1yzZnL6QarfFcJUzOw0CI4O3dLj/CXX XvlQG//7jA4a4XOHYPsrwDyOLDnEWrcJv76DdT8mrevi4M34V9XeOS4fE2qxtjoN6Z FZkMq50QfGJ8Yxuf+W/f6moT2t8WD6F+/uAAepHM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qian Cai , "Paul E. McKenney" , Will Deacon , Sasha Levin Subject: [PATCH 5.4 62/85] arm64/smp: Move rcu_cpu_starting() earlier Date: Mon, 9 Nov 2020 13:55:59 +0100 Message-Id: <20201109125025.543019039@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125022.614792961@linuxfoundation.org> References: <20201109125022.614792961@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qian Cai [ Upstream commit ce3d31ad3cac765484463b4f5a0b6b1f8f1a963e ] The call to rcu_cpu_starting() in secondary_start_kernel() is not early enough in the CPU-hotplug onlining process, which results in lockdep splats as follows: WARNING: suspicious RCU usage ----------------------------- kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!! other info that might help us debug this: RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 no locks held by swapper/1/0. Call trace: dump_backtrace+0x0/0x3c8 show_stack+0x14/0x60 dump_stack+0x14c/0x1c4 lockdep_rcu_suspicious+0x134/0x14c __lock_acquire+0x1c30/0x2600 lock_acquire+0x274/0xc48 _raw_spin_lock+0xc8/0x140 vprintk_emit+0x90/0x3d0 vprintk_default+0x34/0x40 vprintk_func+0x378/0x590 printk+0xa8/0xd4 __cpuinfo_store_cpu+0x71c/0x868 cpuinfo_store_cpu+0x2c/0xc8 secondary_start_kernel+0x244/0x318 This is avoided by moving the call to rcu_cpu_starting up near the beginning of the secondary_start_kernel() function. Signed-off-by: Qian Cai Acked-by: Paul E. McKenney Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/ Link: https://lore.kernel.org/r/20201028182614.13655-1-cai@redhat.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 102dc3e7f2e1d..426409e0d0713 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -215,6 +215,7 @@ asmlinkage notrace void secondary_start_kernel(void) if (system_uses_irq_prio_masking()) init_gic_priority_masking(); + rcu_cpu_starting(cpu); preempt_disable(); trace_hardirqs_off(); -- 2.27.0