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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 EFB7DC433E6 for ; Tue, 1 Sep 2020 15:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBFBD2064B for ; Tue, 1 Sep 2020 15:48:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975319; bh=RJLp00XD7TP+whWdfvsvIJ+pYOGSXaR2waw3YKDqRMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=V+4EmmWHZ0sUgQq3Z5ptfJ6d/4rbo3H+asarwvuDmWQumoAce1/IWy4n3bRQ++TdD aO4VJgfnA4SYFGTj5b3Lz8Lxtwk0H1f4MBgZABcBRSOM9gBVhDK9zEtlnyHubIFHS1 0uzLumJYTuznkBZIbOG2ndnHIJHzxPNFEHatgN88= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732015AbgIAPsh (ORCPT ); Tue, 1 Sep 2020 11:48:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:60764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731843AbgIAPox (ORCPT ); Tue, 1 Sep 2020 11:44:53 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D87BA206FA; Tue, 1 Sep 2020 15:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975092; bh=RJLp00XD7TP+whWdfvsvIJ+pYOGSXaR2waw3YKDqRMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sMwvNnMbV9fNcBUhamDgNjSr/oTytWQES+qy/1ekPM0wuvAbs7GRz4QLbTwTENhOQ C1hvnKy3YO5MK7BFt1DLBqb0Diex+ZAdyC2RNuUHItOqdl7l/OEicMjEO90xixPYQ0 kV1GVB0gcag2I4oWlfbIAjcMMroo1dxRDVmg5h+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Thomas Gleixner Subject: [PATCH 5.8 206/255] genirq/matrix: Deal with the sillyness of for_each_cpu() on UP Date: Tue, 1 Sep 2020 17:11:02 +0200 Message-Id: <20200901151010.573485838@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner commit 784a0830377d0761834e385975bc46861fea9fa0 upstream. Most of the CPU mask operations behave the same way, but for_each_cpu() and it's variants ignore the cpumask argument and claim that CPU0 is always in the mask. This is historical, inconsistent and annoying behaviour. The matrix allocator uses for_each_cpu() and can be called on UP with an empty cpumask. The calling code does not expect that this succeeds but until commit e027fffff799 ("x86/irq: Unbreak interrupt affinity setting") this went unnoticed. That commit added a WARN_ON() to catch cases which move an interrupt from one vector to another on the same CPU. The warning triggers on UP. Add a check for the cpumask being empty to prevent this. Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator") Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- kernel/irq/matrix.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/kernel/irq/matrix.c +++ b/kernel/irq/matrix.c @@ -380,6 +380,13 @@ int irq_matrix_alloc(struct irq_matrix * unsigned int cpu, bit; struct cpumap *cm; + /* + * Not required in theory, but matrix_find_best_cpu() uses + * for_each_cpu() which ignores the cpumask on UP . + */ + if (cpumask_empty(msk)) + return -EINVAL; + cpu = matrix_find_best_cpu(m, msk); if (cpu == UINT_MAX) return -ENOSPC;