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 A8C21C433DB for ; Mon, 28 Dec 2020 03:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6ADA921D81 for ; Mon, 28 Dec 2020 03:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbgL1DRS (ORCPT ); Sun, 27 Dec 2020 22:17:18 -0500 Received: from m15112.mail.126.com ([220.181.15.112]:51046 "EHLO m15112.mail.126.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726408AbgL1DRS (ORCPT ); Sun, 27 Dec 2020 22:17:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=From:Subject:Date:Message-Id; bh=rHDg0EM4Tc1M0YYKA4 UQMqhy0tOgpr+WAMZImhXGOPI=; b=NtHzNaDkdtCeFRfNcfqGRqx3IgKH9zeS3l zRMSm+9FOhhQQIRYnVg5N+i4zKgyO+xHQzDpUNz6BgLZiz1E6+g61pfOlE77N1cy IJQrmGDlqv0DpVj0WAgcWHpOu8BdKAn41HLj/ib6zornorzyZe62JqEpF39pjKdD DqehwFycY= Received: from localhost.localdomain (unknown [36.112.86.14]) by smtp2 (Coremail) with SMTP id DMmowAAX3UDBTOlf7uVwKg--.26924S2; Mon, 28 Dec 2020 11:10:58 +0800 (CST) From: Defang Bo To: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, christophe.leroy@csgroup.eu, akpm@linux-foundation.org, geert@linux-m68k.org, rppt@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Defang Bo Subject: [PATCH] powerpc/mm: add sanity check to avoid null pointer dereference Date: Mon, 28 Dec 2020 11:10:50 +0800 Message-Id: <1609125050-240351-1-git-send-email-bodefang@126.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: DMmowAAX3UDBTOlf7uVwKg--.26924S2 X-Coremail-Antispam: 1Uf129KBjvJXoWrZFW3Cw4xCF17Wr4xuFW3Jrb_yoW8JF4rpw 1vyr1vvw4Fq3Z5KrySkF1DWryYga1ktF1xC39Fk398ua4rtws5uF1fKwnYya13XF95C3WS kFZxKw15Jr13X37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRX_-QUUUUU= X-Originating-IP: [36.112.86.14] X-CM-SenderInfo: pergvwxdqjqiyswou0bp/1tbiFgwJ11pECtLJ6gAAsh Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Similar to commit<0dc294f717d4>("powerpc/mm: bail out early when flushing TLB page"), 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 | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c index 5872f69..1d89335 100644 --- a/arch/powerpc/mm/nohash/tlb.c +++ b/arch/powerpc/mm/nohash/tlb.c @@ -192,6 +192,9 @@ void local_flush_tlb_mm(struct mm_struct *mm) { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); pid = mm->context.id; if (pid != MMU_NO_CONTEXT) @@ -205,8 +208,11 @@ void __local_flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr, { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); - pid = mm ? mm->context.id : 0; + pid = mm->context.id; if (pid != MMU_NO_CONTEXT) _tlbil_va(vmaddr, pid, tsize, ind); preempt_enable(); @@ -268,6 +274,9 @@ void flush_tlb_mm(struct mm_struct *mm) { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); pid = mm->context.id; if (unlikely(pid == MMU_NO_CONTEXT)) -- 2.7.4