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 2FD2CC433F5 for ; Tue, 22 Mar 2022 07:48:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229579AbiCVHuH (ORCPT ); Tue, 22 Mar 2022 03:50:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229586AbiCVHuF (ORCPT ); Tue, 22 Mar 2022 03:50:05 -0400 Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36A96CCC for ; Tue, 22 Mar 2022 00:48:38 -0700 (PDT) Received: by mail-ej1-x62c.google.com with SMTP id qa43so34289926ejc.12 for ; Tue, 22 Mar 2022 00:48:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=q6Ee3t55+IUI0qiEKXzS5vpLkBsJLI1LengAHoJwP3U=; b=jBbXJrWbUYbX/Kec3Spde/WdFH2uOkJ/EshO96cqOSVdQzHbIBeYknC7AVyya7+IX5 whAOgbY+mQ4/xaGGpqWtiqkwqOBMbOUDLeDIulCd7g4sqbu3sT65rZV7TyncIKeBpVvL zHJoKCPm/9aZw/m8X3gFg5CT/Tj8gYbaqZsXAM9cn0meqL1Mjq3r8/Xmewl7EsHMkcll 8DfiP/E0koxPYRADePwp8ANcCAfsf3co7UYtoja9n9B80gi9Bj7E6j/gac8m46w13MHU jRG5Qt3V6Udq/KsUuBiYvEE4JbUPRC5CMa2iMSYZh0DNknCnXQDgH7EPdJ3yJkRRTRZ7 Q1Mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=q6Ee3t55+IUI0qiEKXzS5vpLkBsJLI1LengAHoJwP3U=; b=aQzE2dyv4PvVGeCrGYkK4BQri442OdkHV46Z+wdX/mIhC/a6rhV1JC5bUVtL4b7HFf uj0NeuyDVSVkp+HmJNcaTaKn4MpYlRxTqPNi6UwTjvRDwv4UmuJAsdm1Q9plIDypJx4D Rr7lUPcQcPIGR7obWiPWGZZqAIt50i0P7aBvduK7tS4N9rJG3BO7BGZYtpMSqwnsV/mS yM/IrNrfebr7SN8+4ZsRTA3W+oBtSWmgRBea2l6jl4pg4dsJ8NLDawFP4gQAajHscMID 59SahGqE6+u51ADyAU6B+2Ra9LFMruuYBFEsbpsE/NCoTTu8ligzBgf0bd7J7jpeqfHD 9pTg== X-Gm-Message-State: AOAM533F/x4TbR3qn8Q9Eu11tmWOr7nT3A8fjQKeDNFIV7uVorgtiBx2 pSqJOYIO0ZLYOme6zH4Iwbc= X-Google-Smtp-Source: ABdhPJzp0GSnr4Pyc/HTkH9K/tgLmFJFK8+FiF19DMMDlBFsgyLbv9jeZRWbV7rkpYpb88XyB46izA== X-Received: by 2002:a17:907:216f:b0:6ce:d85f:35cf with SMTP id rl15-20020a170907216f00b006ced85f35cfmr24765695ejb.517.1647935316636; Tue, 22 Mar 2022 00:48:36 -0700 (PDT) Received: from gmail.com (0526ECD0.dsl.pool.telekom.hu. [5.38.236.208]) by smtp.gmail.com with ESMTPSA id a22-20020a50ff16000000b00410d029ea5csm8874938edu.96.2022.03.22.00.48.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Mar 2022 00:48:35 -0700 (PDT) Sender: Ingo Molnar Date: Tue, 22 Mar 2022 08:48:31 +0100 From: Ingo Molnar To: Linus Torvalds Cc: Qian Cai , Linux Kernel Mailing List , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Andrew Morton , Borislav Petkov , Thomas Gleixner , "Huang, Ying" Subject: Re: [GIT PULL] scheduler updates for v5.18 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > * Linus Torvalds wrote: > > > On Mon, Mar 21, 2022 at 6:13 AM Qian Cai wrote: > > > > > > On Mon, Mar 21, 2022 at 11:54:09AM +0100, Ingo Molnar wrote: > > > > Huang Ying (3): > > > > sched/numa-balancing: Move some document to make it consistent with the code > > > > sched/numa: Fix NUMA topology for systems with CPU-less nodes > > > > sched/numa: Avoid migrating task to CPU-less node > > > > > > Linus, I don't think you want to merge this as-is. This will introduce a > > > kernel crash on arm64 NUMA as mentioned in this thread, > > > > Ok, dropped from my queue. Thanks, > > I've reverted the broken commit & will send another pull request after > some testing. Sorry about that! Ended up using the fix below instead - it's tested already on the affected system. Thanks, Ingo =================> From: "Huang, Ying" Date: Tue, 22 Mar 2022 08:39:22 +0100 Subject: [PATCH] sched/numa: Fix boot crash on arm64 systems Qian Cai reported a boot crash on arm64 systems, caused by: 0fb3978b0aac ("sched/numa: Fix NUMA topology for systems with CPU-less nodes") The bug is that node_state() must be supplied a valid node_states[] array index, but in task_numa_placement() the max_nid search can fail with NUMA_NO_NODE, which is not a valid index. Fix it by checking that max_nid is a valid index. [ mingo: Added changelog. ] Fixes: 0fb3978b0aac ("sched/numa: Fix NUMA topology for systems with CPU-less nodes") Reported-by: Qian Cai Tested-by: Qian Cai Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 89d21fda106c..ee0664c9d291 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2437,7 +2437,7 @@ static void task_numa_placement(struct task_struct *p) } /* Cannot migrate task to CPU-less node */ - if (!node_state(max_nid, N_CPU)) { + if (max_nid != NUMA_NO_NODE && !node_state(max_nid, N_CPU)) { int near_nid = max_nid; int distance, near_distance = INT_MAX;