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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 9D6BEC433E0 for ; Fri, 25 Dec 2020 14:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73E612137B for ; Fri, 25 Dec 2020 14:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726545AbgLYOUT (ORCPT ); Fri, 25 Dec 2020 09:20:19 -0500 Received: from mail-m964.mail.126.com ([123.126.96.4]:46796 "EHLO mail-m964.mail.126.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725863AbgLYOUT (ORCPT ); Fri, 25 Dec 2020 09:20:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=From:Subject:Date:Message-Id; bh=iJJoJscBI/+hKpJYBX zopxzPlvxajIEcfsRetkuiDGM=; b=XjcCnFcvScn5ZnrlF73ybd0bpt6l9ERaor knBLj0du7YMzDS+GHBdTtHpS4rPNrUax5QS2odUjMdCcpK70sz9N9rGByaAmPmak iKRzC9sxqMFVAFlQ6JQsRTV05nstUr6xSx3MtJs1uJctOH1X4hFYJBenTj4WLRoq 2II6RPlz0= Received: from localhost.localdomain (unknown [36.112.86.14]) by smtp9 (Coremail) with SMTP id NeRpCgAnXYqakOVfbXMoQA--.6041S2; Fri, 25 Dec 2020 15:11:24 +0800 (CST) From: Defang Bo To: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org Cc: akpm@linux-foundation.org, rppt@kernel.org, christophe.leroy@csgroup.eu, penberg@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Defang Bo Subject: [PATCH] powerpc/mm: avoid null pointer dereference in flush_tlb_mm Date: Fri, 25 Dec 2020 15:11:11 +0800 Message-Id: <1608880271-2294955-1-git-send-email-bodefang@126.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: NeRpCgAnXYqakOVfbXMoQA--.6041S2 X-Coremail-Antispam: 1Uf129KBjvdXoWrKFW5Jw4fury8Kr4rtF1rXrb_yoWxZrgEq3 9xAws7J3yqy3ykZF4kAr4rWF98Aws7ZF4agwn0g34avr90gw4rJFW0q39rGF15WFWIvFWD Xa4Dtr15JF1FvjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7xRRoGQPUUUUU== X-Originating-IP: [36.112.86.14] X-CM-SenderInfo: pergvwxdqjqiyswou0bp/1tbikhwG11pECE6EAAAAsD Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Similar to commit<0dc294f7>, there should be a check for 'mm' to prevent Null pointer dereference in case of 'mm' argument was legitimately passed. Signed-off-by: Defang Bo --- arch/powerpc/mm/nohash/tlb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c index 5872f69..09796c9 100644 --- a/arch/powerpc/mm/nohash/tlb.c +++ b/arch/powerpc/mm/nohash/tlb.c @@ -268,6 +268,9 @@ void flush_tlb_mm(struct mm_struct *mm) { unsigned int pid; + if (unlikely(!mm)) + return; + preempt_disable(); pid = mm->context.id; if (unlikely(pid == MMU_NO_CONTEXT)) -- 2.7.4