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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 03E17C4742C for ; Tue, 3 Nov 2020 01:24:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A08FA2063A for ; Tue, 3 Nov 2020 01:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604366697; bh=zSzP5HQXB/omy2kSYX4NQ2xb5+Etbw0aaVboM/t07gE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S4PlWbKAItESGFyeoTukywz4UHE2z/1ylmJCyx/6+cNwddIZQ/GXRs6Dg8YHHWdG7 ZqrZ1x3EJ766oQiHGKIoX8fnpm78Yu8BqVnn/Rn47uNR3BNoh1PcsfPU1Qgv5khOKO CZjFwTcbZUs3YiO+DGVrryuu7KkbNOL4E8V3nz0U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728391AbgKCBY4 (ORCPT ); Mon, 2 Nov 2020 20:24:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:34532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728003AbgKCBUH (ORCPT ); Mon, 2 Nov 2020 20:20:07 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 917D722447; Tue, 3 Nov 2020 01:20:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604366406; bh=zSzP5HQXB/omy2kSYX4NQ2xb5+Etbw0aaVboM/t07gE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wbPYWg24J2ksTvmgvoxtoUJ/DohzVKGii7DpWPeEOPIFRJaQ9GEiIbV0Tgw4Ivcep oSq5415uf7/D6sXLLzKrCOu+R5Zd9YllzamkboG0viLeItsGinZf7GEs896lw43kWy vNtfN3+d+UJRPMdqsjMPGS7xYCV2rJe98hwsmDng= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qian Cai , "Paul E . McKenney" , Will Deacon , Sasha Levin , linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.8 29/29] arm64/smp: Move rcu_cpu_starting() earlier Date: Mon, 2 Nov 2020 20:19:28 -0500 Message-Id: <20201103011928.183145-29-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201103011928.183145-1-sashal@kernel.org> References: <20201103011928.183145-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 8cd6316a0d833..3e0fd4e6bcdcb 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -214,6 +214,7 @@ 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