From patchwork Thu Mar 31 15:39:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Phil Auld X-Patchwork-Id: 12797376 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0E431C433F5 for ; Thu, 31 Mar 2022 15:40:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=WVtoBQAiKCkMAZqO8T5lBwdYgZCPlIqFmC7KxafE97w=; b=QTKXfkDPBFx7i4 jt2b4GsJEafcCXbJNBqZFjEnQU0yzdl6gikCCgE/A0JIrpwvRgEem9H8zhlYD9B9s2nBwGz4ctt/O ndt1Wl2FLdiBkP8DZgwgNEGuoqOk+plWTdlnhbN1/qHIyF9h/uOq3HHtAzWbfqf3TS+25dB4UfnKX AuwXIoIwaY/eVQIf/GNftlU9eefczVEn94SfoFXTt1FnqnwHbKk8APb+Q7FpBklPGp2lO/aT7cP+j rt3sz/hZLPk72xcFmU9TUKKB5RL5FsXWdH763tzg9bxQPmiaLek2ZBR6djRta5gsZhjthieQiibhL gcoXDMyWmQY0gZMZ5bSg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZwtb-002lVY-B5; Thu, 31 Mar 2022 15:39:35 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZwtX-002lTb-AP for linux-arm-kernel@lists.infradead.org; Thu, 31 Mar 2022 15:39:33 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648741169; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=HGNBKdVLy2ioTvnPQV3bpsQMS1zK36BBjUbEXrjr8xA=; b=LHIKEZkq0vC+xgNH1Cdav6q+gn8y+iNKvgL3PYCjUaESepiG/lj8B+uQqHSS8w8g1F6In+ aHhwbBGvh04nezTuPihOK2iJc8hFMAKvxzbRTOtlhWJH0z4b80IVuaxXcGGsPjcRPk3BNP bqpJPFUvWYoQQm9P+IrrqUPIy1jISms= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-477-TAsf-1w-MVWchVhuC-zIDw-1; Thu, 31 Mar 2022 11:39:28 -0400 X-MC-Unique: TAsf-1w-MVWchVhuC-zIDw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 969213C16193; Thu, 31 Mar 2022 15:39:27 +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 5CAF7400E42D; Thu, 31 Mar 2022 15:39:27 +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 v3] arch/arm64: Fix topology initialization for core scheduling Date: Thu, 31 Mar 2022 11:39:26 -0400 Message-Id: <20220331153926.25742-1-pauld@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220331_083931_469173_2D63E4EF X-CRM114-Status: GOOD ( 15.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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. With smt_mask not setup correctly we bail on `cpumask_weight(smt_mask) == 1` for !leaders in: notify_cpu_starting() cpuhp_invoke_callback_range() sched_cpu_starting() sched_core_cpu_starting() which leads to rq->core not being correctly set for !leader-rq's. Without this change stress-ng (which enables core scheduling in its prctl tests in newer versions -- i.e. with PR_SCHED_CORE support) 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 Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann --- 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); /*