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=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 C4AF4C433E2 for ; Fri, 17 Jul 2020 01:05:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 729FF207BC for ; Fri, 17 Jul 2020 01:05:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 729FF207BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C6AD58D0001; Thu, 16 Jul 2020 21:05:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C1B966B006E; Thu, 16 Jul 2020 21:05:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B31628D0001; Thu, 16 Jul 2020 21:05:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 99D2E6B0037 for ; Thu, 16 Jul 2020 21:05:05 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5217E248E for ; Fri, 17 Jul 2020 01:05:05 +0000 (UTC) X-FDA: 77045773770.21.dress71_0c08e4426f06 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 15DA9180442C3 for ; Fri, 17 Jul 2020 01:05:05 +0000 (UTC) X-HE-Tag: dress71_0c08e4426f06 X-Filterd-Recvd-Size: 3097 Received: from huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Fri, 17 Jul 2020 01:05:04 +0000 (UTC) Received: from DGGEMM403-HUB.china.huawei.com (unknown [172.30.72.54]) by Forcepoint Email with ESMTP id 37FDBF49E21E86D6E257; Fri, 17 Jul 2020 09:04:57 +0800 (CST) Received: from dggeme703-chm.china.huawei.com (10.1.199.99) by DGGEMM403-HUB.china.huawei.com (10.3.20.211) with Microsoft SMTP Server (TLS) id 14.3.487.0; Fri, 17 Jul 2020 09:04:56 +0800 Received: from dggeme753-chm.china.huawei.com (10.3.19.99) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1913.5; Fri, 17 Jul 2020 09:04:56 +0800 Received: from dggeme753-chm.china.huawei.com ([10.7.64.70]) by dggeme753-chm.china.huawei.com ([10.7.64.70]) with mapi id 15.01.1913.007; Fri, 17 Jul 2020 09:04:56 +0800 From: linmiaohe To: Andrew Morton CC: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] mm: mmap: Merge vma after call_mmap() if possible Thread-Topic: [PATCH] mm: mmap: Merge vma after call_mmap() if possible Thread-Index: AdZb1cr2oR2Sm1QnnkShPIMChGHNoQ== Date: Fri, 17 Jul 2020 01:04:56 +0000 Message-ID: <6de8156c657a42e7a6acc24a5234b637@huawei.com> Accept-Language: en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.174.176.109] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 15DA9180442C3 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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: Andrew Morton wrote: >On Tue, 14 Jul 2020 11:07:44 +0800 linmiaohe wrote: > >> From: Miaohe Lin >>=20 >> The vm_flags may be changed after call_mmap() because drivers may set=20 >> some flags for their own purpose. As a result, we failed to merge the=20 >> adjacent vma due to the different vm_flags as userspace can't pass in th= e same one. >> Try to merge vma after call_mmap() to fix this issue. >>=20 >> Signed-off-by: Hongxiang Lou >> Signed-off-by: Miaohe Lin >> --- >> + /* If vm_flags changed after call_mmap(), we should try merge vma aga= in >> + * as we may succeed this time. >> + */ >> + if (unlikely(vm_flags !=3D vma->vm_flags && prev)) { >> + merge =3D vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_fl= ags, >> + NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX); >> + if (merge) { >> + fput(file); >> + vm_area_free(vma); >> + vma =3D merge; >> + goto unmap_writable; > >Shouldn't we update local variable `vm_flags' here, to pick up the change?= And possibly `addr'? Yes, we should. `vm_flags` and `addr` should be updated to continue the wor= k. Many thanks for your great review. I will fix it and test again. I will send a patch v2 soon.