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=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 7FCD6C433DB for ; Tue, 29 Dec 2020 20:52:21 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 873C321D1B for ; Tue, 29 Dec 2020 20:52:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 873C321D1B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=126.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4D566p135QzDqHf for ; Wed, 30 Dec 2020 07:52:18 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=126.com (client-ip=123.126.96.4; helo=mail-m964.mail.126.com; envelope-from=bodefang@126.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=126.com Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=126.com header.i=@126.com header.a=rsa-sha256 header.s=s110527 header.b=XjcCnFcv; dkim-atps=neutral X-Greylist: delayed 1917 seconds by postgrey-1.36 at bilbo; Fri, 25 Dec 2020 18:45:08 AEDT Received: from mail-m964.mail.126.com (mail-m964.mail.126.com [123.126.96.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4D2JrN3FDczDqJ7 for ; Fri, 25 Dec 2020 18:45:07 +1100 (AEDT) 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 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 X-Mailman-Approved-At: Wed, 30 Dec 2020 07:50:45 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, penberg@kernel.org, Defang Bo , akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, rppt@kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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