Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755260AbdCXNyW (ORCPT ); Fri, 24 Mar 2017 09:54:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43074 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751759AbdCXNyF (ORCPT ); Fri, 24 Mar 2017 09:54:05 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 3B403C009DEF Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=msalter@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 3B403C009DEF From: Mark Salter To: Will Deacon Cc: Mark Rutland , Pratyush Anand , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64: fix NULL dereference in have_cpu_die() Date: Fri, 24 Mar 2017 09:53:56 -0400 Message-Id: <20170324135356.25881-1-msalter@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 24 Mar 2017 13:54:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 29 Commit 5c492c3f5255 ("arm64: smp: Add function to determine if cpus are stuck in the kernel") added a helper function to determine if die() is supported in cpu_ops. This function assumes a cpu will have a valid cpu_ops entry, but that may not be the case for cpu0 is spin-table or parking protocol is used to boot secondary cpus. In that case, there is a NULL dereference if have_cpu_die() is called by cpu0. So add a check for a valid cpu_ops before dereferencing it. Fixes: 5c492c3f5255 ("arm64: smp: Add function to determine if cpus are stuck in the kernel") Signed-off-by: Mark Salter --- 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 ef1caae..9b10365 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -944,7 +944,7 @@ static bool have_cpu_die(void) #ifdef CONFIG_HOTPLUG_CPU int any_cpu = raw_smp_processor_id(); - if (cpu_ops[any_cpu]->cpu_die) + if (cpu_ops[any_cpu] && cpu_ops[any_cpu]->cpu_die) return true; #endif return false; -- 2.9.3