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 405E4C072A2 for ; Wed, 15 Nov 2023 19:32:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234063AbjKOTcT (ORCPT ); Wed, 15 Nov 2023 14:32:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234108AbjKOTb7 (ORCPT ); Wed, 15 Nov 2023 14:31:59 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FD761A7 for ; Wed, 15 Nov 2023 11:31:56 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A687C433C9; Wed, 15 Nov 2023 19:31:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700076716; bh=vL5sD+wXikLpB0SNAPvF/KJGavoA5i8niOhW5vRw8t0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RZW6VC3nmghqg4kAMWmb+sICSM1gc93pbbfdkhj1c3hsx/sFDVlKwpicAgEsCu4tG uNexRBNzYJOLipQtYUJPO4GcoY2aozMO/5l5hRo2JbPBn9zv0z4v4fI8eFFKVPyWeN rvHpLVUUM4UhNp/njh28aRXJ2gcTw72y5WzhLIOg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yicong Yang , Guenter Roeck , Yury Norov , Ingo Molnar , Mel Gorman , Sasha Levin Subject: [PATCH 6.6 003/603] sched/topology: Fix sched_numa_find_nth_cpu() in CPU-less case Date: Wed, 15 Nov 2023 14:09:08 -0500 Message-ID: <20231115191613.361360889@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115191613.097702445@linuxfoundation.org> References: <20231115191613.097702445@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yury Norov [ Upstream commit 617f2c38cb5ce60226042081c09e2ee3a90d03f8 ] When the node provided by user is CPU-less, corresponding record in sched_domains_numa_masks is not set. Trying to dereference it in the following code leads to kernel crash. To avoid it, start searching from the nearest node with CPUs. Fixes: cd7f55359c90 ("sched: add sched_numa_find_nth_cpu()") Reported-by: Yicong Yang Reported-by: Guenter Roeck Signed-off-by: Yury Norov Signed-off-by: Ingo Molnar Reviewed-by: Yicong Yang Cc: Mel Gorman Link: https://lore.kernel.org/r/20230819141239.287290-4-yury.norov@gmail.com Closes: https://lore.kernel.org/lkml/CAAH8bW8C5humYnfpW3y5ypwx0E-09A3QxFE1JFzR66v+mO4XfA@mail.gmail.com/T/ Closes: https://lore.kernel.org/lkml/ZMHSNQfv39HN068m@yury-ThinkPad/T/#mf6431cb0b7f6f05193c41adeee444bc95bf2b1c4 Signed-off-by: Sasha Levin --- kernel/sched/topology.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 05a5bc678c089..423d08947962c 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -2122,12 +2122,16 @@ static int hop_cmp(const void *a, const void *b) */ int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node) { - struct __cmp_key k = { .cpus = cpus, .node = node, .cpu = cpu }; + struct __cmp_key k = { .cpus = cpus, .cpu = cpu }; struct cpumask ***hop_masks; int hop, ret = nr_cpu_ids; rcu_read_lock(); + /* CPU-less node entries are uninitialized in sched_domains_numa_masks */ + node = numa_nearest_node(node, N_CPU); + k.node = node; + k.masks = rcu_dereference(sched_domains_numa_masks); if (!k.masks) goto unlock; -- 2.42.0