From patchwork Mon Nov 9 12:56:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 322719 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 A66E2C2D0A3 for ; Mon, 9 Nov 2020 13:20:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CAD9206D8 for ; Mon, 9 Nov 2020 13:20:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604928036; bh=v/A80OfUdI2AyrGVlqxGk0BEl2vN5DxgvY1qGsxjCmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=u0y6wpfmZ9GruEjNHRmuIVuNWCi1S46y1R8CpKQeGT3LkDXpmH3gVsUX09gmrIKmH lqmP0uFI0OE152TNxkZnJ63L5A3wN0FlIPGjpYc2tmlGcXbtTIeZp8TqCJucglBA32 zzJgqyQbwUuym9NTSL4H6UcMqL3BBcwv9dOixtyE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387483AbgKINUf (ORCPT ); Mon, 9 Nov 2020 08:20:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:48116 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387475AbgKINUc (ORCPT ); Mon, 9 Nov 2020 08:20:32 -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 032282083B; Mon, 9 Nov 2020 13:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604928030; bh=v/A80OfUdI2AyrGVlqxGk0BEl2vN5DxgvY1qGsxjCmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kMmfLZyI6PhtrfYhjhT9+Tpy4hO5y/pdcHfGlidj7Qrhbsz4oPse4MtHzfd6EgsCi xUcWQYsouiYlOW6ltTXMVkc/xYKNs0OkbH5Ikjg4oEfpibDYjqiXyvUmUrxA+hkbCC DGNt61jS+X2earo31Otn6X6Cfhyx/JlaVXAArg6A= 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 5.9 104/133] arm64/smp: Move rcu_cpu_starting() earlier Date: Mon, 9 Nov 2020 13:56:06 +0100 Message-Id: <20201109125035.690427751@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125030.706496283@linuxfoundation.org> References: <20201109125030.706496283@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 355ee9eed4dde..98c059b6bacae 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -213,6 +213,7 @@ 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();