From patchwork Tue Apr 7 09:51:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miles Chen X-Patchwork-Id: 11477835 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D177492A for ; Tue, 7 Apr 2020 09:51:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 AF836206F7 for ; Tue, 7 Apr 2020 09:51:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="VmgYGDVz"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="iNG2m24U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF836206F7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mediatek-bounces+patchwork-linux-mediatek=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=IJamtL+kcyq1dq2LyA7o/flEfoTMFHAnZtj5Wcd0OPo=; b=VmgYGDVzJb9671 qBqZpIUGcHG8O0gjq98BIEYLikakqyTla2UZq+FdHWjgkMAHBZNwPnujPnd5Cu5uolJ0JGBy6zQqI JMJST2BJZGiw0v2AqQAFur3HjgdgwAj44BZaKyrfXXZ9KznV8NFa+bllKSKCrRcyPTbTT3GmxLEy+ RIc/1bfNwF9JyYED4tfikISgn36rRycdlFCx/7DvfzSdiDOyb+49zgdcmBE5mlqaxmhF9stTRkrH4 etl94bz6Bh2H6CBbK0fpRqYzmiQagAhUx46ijP1YX2Hz0yWhY6l/PG9ov0+8z3a4RuisXYM+2ZMko txL6Af/kltyfqnWkZyDg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLkt8-000270-Se; Tue, 07 Apr 2020 09:51:22 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLkt6-00025x-Q7 for linux-mediatek@lists.infradead.org; Tue, 07 Apr 2020 09:51:22 +0000 X-UUID: f9016c1715ca4630873693abfa8b14a0-20200407 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=XLhZCqqQ+XAe7Id+sLkm1mR2JnMwc/iwpAHwXkCFgUQ=; b=iNG2m24UbyP+zalcyLC9KtRSw+sVWZcos6iUdHCiqUfyRjX/A6WHvCt5MzK2MAaeH2s5WS0YR6d0KEiPRIf1RtdA2y2MG9I7Z2sXezcxqQiiYPdoyoxc2c9XMqFMiTI89LWTY55hBDqOpx+EfxjKpUvO7mtVsPyqbVWj/ac/v8I=; X-UUID: f9016c1715ca4630873693abfa8b14a0-20200407 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 419721831; Tue, 07 Apr 2020 01:51:19 -0800 Received: from MTKMBS06N2.mediatek.inc (172.21.101.130) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 7 Apr 2020 02:51:13 -0700 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs06n2.mediatek.inc (172.21.101.130) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 7 Apr 2020 17:51:10 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 7 Apr 2020 17:51:09 +0800 From: Miles Chen To: Andrew Morton Subject: [PATCH] mm/gup: fix null pointer dereference detected by coverity Date: Tue, 7 Apr 2020 17:51:07 +0800 Message-ID: <20200407095107.1988-1-miles.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-TM-SNTS-SMTP: F11F2E2A2FF92E73BAB9EDC1B554CE3E5CCB1D0ABAD6F0EF683C94EC7DB3A3AF2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200407_025120_853378_A37C177B X-CRM114-Status: UNSURE ( 9.43 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [216.200.240.184 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 MIME_BASE64_TEXT RAW: Message text disguised using base64 encoding -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, Miles Chen , linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, wsd_upstream@mediatek.com Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+patchwork-linux-mediatek=patchwork.kernel.org@lists.infradead.org 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); ... } Fixes: 4a9e1cda2748 ("mm: bring in additional flag for fixup_user_fault to signal unlock") Signed-off-by: Miles Chen Reviewed-by: Ira Weiny Acked-by: Souptick Joarder --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index da3e03185144..a68d11dc232d 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1230,7 +1230,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, 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; }