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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 E18B4C2BB55 for ; Fri, 10 Apr 2020 21:32:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A2AF520801 for ; Fri, 10 Apr 2020 21:32:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qrK9+Iha" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2AF520801 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 56E378E006A; Fri, 10 Apr 2020 17:32:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 544CD8E0067; Fri, 10 Apr 2020 17:32:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 434358E006A; Fri, 10 Apr 2020 17:32:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0006.hostedemail.com [216.40.44.6]) by kanga.kvack.org (Postfix) with ESMTP id 2480F8E0067 for ; Fri, 10 Apr 2020 17:32:37 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D8313824556B for ; Fri, 10 Apr 2020 21:32:36 +0000 (UTC) X-FDA: 76693244712.11.door74_33e16d120da0a X-HE-Tag: door74_33e16d120da0a X-Filterd-Recvd-Size: 2686 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Fri, 10 Apr 2020 21:32:36 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 7383A20753; Fri, 10 Apr 2020 21:32:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586554355; bh=h2IuCHwCAQeela/hIkcA7lcc8Xrz9jtSjAy7CiDKX4M=; h=Date:From:To:Subject:In-Reply-To:From; b=qrK9+Iha7bepmCH4E4/5k6wBHZcMvHBYOgIbqDfYKAtn3uV7kG3be4D1fqmzig//V Z/pEB0rqKz+2+vtuNUER2LMdxO1c5tnJ1RekxmOg+ySBx+cwR2JvkYWD4+wpgZod5i +SGqLVw0SaxK7X+AcUuaZXMB4iiOukMt0HccpIqE= Date: Fri, 10 Apr 2020 14:32:35 -0700 From: Andrew Morton To: akpm@linux-foundation.org, ira.weiny@intel.com, linux-mm@kvack.org, miles.chen@mediatek.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 07/35] mm/gup: fix null pointer dereference detected by coverity Message-ID: <20200410213235.M6eTaELL2%akpm@linux-foundation.org> In-Reply-To: <20200410143047.bf34a933ce1affdc042c7c80@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Miles Chen Subject: mm/gup: fix null pointer dereference detected by coverity In fixup_user_fault(), it is possible that unlocked is NULL, so we should test unlocked before using it. For example, in arch/arc/kernel/process.c, NULL is passed to fixup_user_fault(). SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) { ... ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr, FAULT_FLAG_WRITE, NULL); ... } Link: http://lkml.kernel.org/r/20200407095107.1988-1-miles.chen@mediatek.com Fixes: 4a9e1cda2748 ("mm: bring in additional flag for fixup_user_fault to signal unlock") Signed-off-by: Miles Chen Reviewed-by: Ira Weiny Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/gup.c~mm-gup-fix-null-pointer-dereference-detected-by-coverity +++ a/mm/gup.c @@ -1231,7 +1231,8 @@ retry: if (ret & VM_FAULT_RETRY) { down_read(&mm->mmap_sem); if (!(fault_flags & FAULT_FLAG_TRIED)) { - *unlocked = true; + if (unlocked) + *unlocked = true; fault_flags |= FAULT_FLAG_TRIED; goto retry; } _