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 36C6AC433EF for ; Wed, 30 Mar 2022 15:56:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348457AbiC3P6O (ORCPT ); Wed, 30 Mar 2022 11:58:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348593AbiC3P6C (ORCPT ); Wed, 30 Mar 2022 11:58:02 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8ECD115FED for ; Wed, 30 Mar 2022 08:56:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648655776; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=OAKeevVq2uim2I3bStMAlMgog9psP1nOaTVNXMX0TeQ=; b=jE2vI6pVDHFbzCWEH1F+A9np4Exx4jbJGcE4Z18SrWN9kg527PbYdwH+dr++M9jNERmjZK zHSCZTN6J3WaNM3Bj9b1hSbKwmdO6aNSP1P66GYvTA1yTtUmqONUP4lpdffaUlfzVV7R6c hCoEoXALnfS2K8WHzdDaMEosTDI/9PM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-610-atDwIMjgMQ68Rmta3jub-g-1; Wed, 30 Mar 2022 11:56:12 -0400 X-MC-Unique: atDwIMjgMQ68Rmta3jub-g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 677E7811E75; Wed, 30 Mar 2022 15:56:12 +0000 (UTC) Received: from pauld.bos.com (dhcp-17-51.bos.redhat.com [10.18.17.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E8F7141DECD; Wed, 30 Mar 2022 15:56:12 +0000 (UTC) From: Phil Auld To: linux-kernel@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Mark Rutland , Peter Zijlstra , linux-arm-kernel@lists.infradead.org, Dietmar Eggemann Subject: [PATCH v2] arch/arm64: Fix topology initialization for core scheduling Date: Wed, 30 Mar 2022 11:56:11 -0400 Message-Id: <20220330155611.30216-1-pauld@redhat.com> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arm64 systems rely on store_cpu_topology() to call update_siblings_masks() to transfer the toplogy to the various cpu masks. This needs to be done before the call to notify_cpu_starting() which tells the scheduler about each cpu found, otherwise the core scheduling data structures are setup in a way that does not match the actual topology. Without this change stress-ng (which enables core scheduling in its prctl tests) causes a warning and then a crash (trimmed for legibility): [ 1853.805168] ------------[ cut here ]------------ [ 1853.809784] task_rq(b)->core != rq->core [ 1853.809792] WARNING: CPU: 117 PID: 0 at kernel/sched/fair.c:11102 cfs_prio_less+0x1b4/0x1c4 ... [ 1854.015210] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 ... [ 1854.231256] Call trace: [ 1854.233689] pick_next_task+0x3dc/0x81c [ 1854.237512] __schedule+0x10c/0x4cc [ 1854.240988] schedule_idle+0x34/0x54 Fixes: 9edeaea1bc45 ("sched: Core-wide rq->lock") Signed-off-by: Phil Auld --- This is a similar issue to f2703def339c ("MIPS: smp: fill in sibling and core maps earlier") which fixed it for MIPS. v2: Fixed the commit message. No code change. arch/arm64/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 27df5c1e6baa..3b46041f2b97 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -234,6 +234,7 @@ asmlinkage notrace void secondary_start_kernel(void) * Log the CPU info before it is marked online and might get read. */ cpuinfo_store_cpu(); + store_cpu_topology(cpu); /* * Enable GIC and timers. @@ -242,7 +243,6 @@ asmlinkage notrace void secondary_start_kernel(void) ipi_setup(cpu); - store_cpu_topology(cpu); numa_add_cpu(cpu); /* -- 2.18.0