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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 E5EDAC433FF for ; Thu, 1 Aug 2019 18:43:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE9602087E for ; Thu, 1 Aug 2019 18:43:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="h+0IcRmz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732967AbfHASnD (ORCPT ); Thu, 1 Aug 2019 14:43:03 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:3214 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731751AbfHASnC (ORCPT ); Thu, 1 Aug 2019 14:43:02 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x71IZYam006898 for ; Thu, 1 Aug 2019 11:43:02 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=U9VgRs98GbU87xGfDbgwnxYoI5hIm/KB7jgPU3pbj0k=; b=h+0IcRmzWSwWGwzzn7mE9a8id0EgPb+kaehHVQVuXTNWvHk7/bt94DL0hmDrKCw9wNzS r6KkPql6FPRNoVfypIR1Xb3b5z6qtpg3uKka+aiKZNoabIlKI0BOEVIWtZ29tBYmu6z5 F88sGWzHcdUkPwHSA2r0ms/6KdFB1uCCbpM= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2u3xmta25s-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 01 Aug 2019 11:43:02 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Thu, 1 Aug 2019 11:42:59 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id B26D962E1E18; Thu, 1 Aug 2019 11:42:56 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: , , CC: , , , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v10 1/7] filemap: check compound_head(page)->mapping in filemap_fault() Date: Thu, 1 Aug 2019 11:42:38 -0700 Message-ID: <20190801184244.3169074-2-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190801184244.3169074-1-songliubraving@fb.com> References: <20190801184244.3169074-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-01_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=887 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908010193 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, filemap_fault() avoids race condition with truncate by checking page->mapping == mapping. This does not work for compound pages. This patch let it check compound_head(page)->mapping instead. Acked-by: Rik van Riel Acked-by: Kirill A. Shutemov Acked-by: Johannes Weiner Signed-off-by: Song Liu --- mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/filemap.c b/mm/filemap.c index 7161fb937e78..d0bd9e585c2f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2537,7 +2537,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) goto out_retry; /* Did it get truncated? */ - if (unlikely(page->mapping != mapping)) { + if (unlikely(compound_head(page)->mapping != mapping)) { unlock_page(page); put_page(page); goto retry_find; -- 2.17.1