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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 419A2C43381 for ; Tue, 26 Feb 2019 06:44:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EA4D7213A2 for ; Tue, 26 Feb 2019 06:44:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA4D7213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 83A738E0004; Tue, 26 Feb 2019 01:44:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7E9338E0002; Tue, 26 Feb 2019 01:44:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 68A098E0004; Tue, 26 Feb 2019 01:44:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 0AB4D8E0002 for ; Tue, 26 Feb 2019 01:44:03 -0500 (EST) Received: by mail-ed1-f72.google.com with SMTP id u12so4984643edo.5 for ; Mon, 25 Feb 2019 22:44:02 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:references:mime-version:content-disposition:in-reply-to :user-agent:message-id; bh=hvjYjwHw9BhznjaBKo6VPFZdw85WBC+PsabC7jzHKXw=; b=hQvt9P+rrlieLj0wC1XtAkfkwqEykFMy3do68F19HvVJaNtNSMtYZc55ijjtxsVNxm OcYN3e4BNH/C3ncdJ3UE4WMa9r3MJ0FYrqkg8Vq3rV0QC/iHV5zLWYp33bC2b7YjdBuc 4FPiYaQ2zt16xBKwgGCM/Lgu8gpwfAIH3K8eaS1H5/iCjimk5R2vfvurSV377UnTM5KI f42/moOCrCwX6j7H88xGXQCZk4XQ27ZtgxUCFON2zZltlMUV9AQeV4xM7n45O6LzYZxJ Rl/GhPQou3crr1HrdNh5TparyZZLJI7M63XkiWhNZUYIo2UAmzP8qc9DKzB/m5WrRaUd cQog== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com X-Gm-Message-State: AHQUAuZPvt8KC8h088KbA8FmQ+GU3A1p9okHXoHQiz/G4v9EX5PU7c7C EcptJOQNmHm/cZoiREs9Iml3CV+m6rl6Qy9iss5cxR66ulBWc45B/zPwBEw6MM/NbPvYrQHtB0L rVgQE+IekitTIaqsWPiqw4ygMSlMuHOFGYluPisVdMD7JvcWxTW/dwzXkVB5Cq7wsKQ== X-Received: by 2002:a17:906:49d9:: with SMTP id w25mr13947518ejv.52.1551163442560; Mon, 25 Feb 2019 22:44:02 -0800 (PST) X-Google-Smtp-Source: AHgI3IbU1YrmOC0WO3zgfH1pPs/c8pu5MBYAHh8GSmhZTuAPB2IxwIuPV3G34HXNgzuylo5+rJyM X-Received: by 2002:a17:906:49d9:: with SMTP id w25mr13947484ejv.52.1551163441731; Mon, 25 Feb 2019 22:44:01 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1551163441; cv=none; d=google.com; s=arc-20160816; b=flDW0F9BDdiGFRwfZzMJ7bdrLvGgv0c+4KNC0MOjXLW55mT04gwoRaPdo0WR/LjyYR r9UcVnCeC9EI3jWV3wy/BPTr2zEdCPNqKBZtaTlYTu9v4erJI0RxwiB2k13LIBHgx2J4 F9u9K7aKG9FjiplTj4OGbhST/m+4zMdB774QwVqIDINvmRlXSPrkrVcSsa04LS4sPuCX gdgIlGz7RMeUWeuMuhWkEypo1RYlkjylalpc+KL4ZExdSKDSorzYQgSKp/fNBLhCA0pS vgoUkZ9zl0gUGIt9rFol6XU7j55DCKyT1wf2z1szXitpLhRrTaDjFjKDdm776UP/MKaw WpQQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:user-agent:in-reply-to:content-disposition:mime-version :references:subject:cc:to:from:date; bh=hvjYjwHw9BhznjaBKo6VPFZdw85WBC+PsabC7jzHKXw=; b=Ytzbm7Dtpu6alIRxK6ohc912+ySG6hSvVBAXBfR+lCqIthXbAOXvgnslTKYZHuHS3D wvzGNI8rzYFzH0u+kFT8SSYiXq+3hjZkKn96AHClUBG8Fkdu8bGhxyE0i6C4jaHEX7mc fqJrwh9FDgnaCxVuYxQw9h07PwhumVGdgMJPeBCilWjrOrpR8ruAYLRVBcM0aO0qvYGy w90qS0UXg7N3XX44CKOH4pgc55Z27IQXI2RxDD1A/WX9dNwHvD2VVDoxuRtCus1Lnup7 biVpKJMYe4bGVk+jDaDmuJokgvwNKtAv3ysY8KOL1EvAtSyeAkHWKYzFT26kYidFtZke oKNw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id x9si33928edx.107.2019.02.25.22.44.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 22:44:01 -0800 (PST) Received-SPF: pass (google.com: domain of rppt@linux.ibm.com designates 148.163.158.5 as permitted sender) client-ip=148.163.158.5; Authentication-Results: mx.google.com; spf=pass (google.com: domain of rppt@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=rppt@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1Q6havW172896 for ; Tue, 26 Feb 2019 01:44:00 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2qvym2t97h-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 26 Feb 2019 01:44:00 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 26 Feb 2019 06:43:58 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp07.uk.ibm.com (192.168.101.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 26 Feb 2019 06:43:52 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1Q6hoQX25296898 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 26 Feb 2019 06:43:51 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E114011C04A; Tue, 26 Feb 2019 06:43:50 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7BF4511C052; Tue, 26 Feb 2019 06:43:49 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.8.84]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 26 Feb 2019 06:43:49 +0000 (GMT) Date: Tue, 26 Feb 2019 08:43:47 +0200 From: Mike Rapoport To: Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" , Rik van Riel Subject: Re: [PATCH v2 20/26] userfaultfd: wp: support write protection for userfault vma range References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-21-peterx@redhat.com> <20190225205233.GC10454@rapoport-lnx> <20190226060627.GG13653@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190226060627.GG13653@xz-x1> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19022606-0028-0000-0000-0000034D0EEF X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19022606-0029-0000-0000-0000240B6098 Message-Id: <20190226064347.GB5873@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-26_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902260051 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: On Tue, Feb 26, 2019 at 02:06:27PM +0800, Peter Xu wrote: > On Mon, Feb 25, 2019 at 10:52:34PM +0200, Mike Rapoport wrote: > > On Tue, Feb 12, 2019 at 10:56:26AM +0800, Peter Xu wrote: > > > From: Shaohua Li > > > > > > Add API to enable/disable writeprotect a vma range. Unlike mprotect, > > > this doesn't split/merge vmas. > > > > > > Cc: Andrea Arcangeli > > > Cc: Rik van Riel > > > Cc: Kirill A. Shutemov > > > Cc: Mel Gorman > > > Cc: Hugh Dickins > > > Cc: Johannes Weiner > > > Signed-off-by: Shaohua Li > > > Signed-off-by: Andrea Arcangeli > > > [peterx: > > > - use the helper to find VMA; > > > - return -ENOENT if not found to match mcopy case; > > > - use the new MM_CP_UFFD_WP* flags for change_protection > > > - check against mmap_changing for failures] > > > Signed-off-by: Peter Xu > > > --- > > > include/linux/userfaultfd_k.h | 3 ++ > > > mm/userfaultfd.c | 54 +++++++++++++++++++++++++++++++++++ > > > 2 files changed, 57 insertions(+) > > > > > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > > > index 765ce884cec0..8f6e6ed544fb 100644 > > > --- a/include/linux/userfaultfd_k.h > > > +++ b/include/linux/userfaultfd_k.h > > > @@ -39,6 +39,9 @@ extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, > > > unsigned long dst_start, > > > unsigned long len, > > > bool *mmap_changing); > > > +extern int mwriteprotect_range(struct mm_struct *dst_mm, > > > + unsigned long start, unsigned long len, > > > + bool enable_wp, bool *mmap_changing); > > > > > > /* mm helpers */ > > > static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, > > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > > > index fefa81c301b7..529d180bb4d7 100644 > > > --- a/mm/userfaultfd.c > > > +++ b/mm/userfaultfd.c > > > @@ -639,3 +639,57 @@ ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start, > > > { > > > return __mcopy_atomic(dst_mm, start, 0, len, true, mmap_changing, 0); > > > } > > > + > > > +int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, > > > + unsigned long len, bool enable_wp, bool *mmap_changing) > > > +{ > > > + struct vm_area_struct *dst_vma; > > > + pgprot_t newprot; > > > + int err; > > > + > > > + /* > > > + * Sanitize the command parameters: > > > + */ > > > + BUG_ON(start & ~PAGE_MASK); > > > + BUG_ON(len & ~PAGE_MASK); > > > + > > > + /* Does the address range wrap, or is the span zero-sized? */ > > > + BUG_ON(start + len <= start); > > > > I'd replace these BUG_ON()s with > > > > if (WARN_ON()) > > return -EINVAL; > > I believe BUG_ON() is used because these parameters should have been > checked in userfaultfd_writeprotect() already by the common > validate_range() even before calling mwriteprotect_range(). So I'm > fine with the WARN_ON() approach but I'd slightly prefer to simply > keep the patch as is to keep Jerome's r-b if you won't disagree. :) Right, userfaultfd_writeprotect() should check these parameters and if it didn't it was a bug indeed. But still, it's not severe enough to crash the kernel. I hope Jerome wouldn't mind to keep his r-b with s/BUG_ON/WARN_ON ;-) With this change you can also add Reviewed-by: Mike Rapoport > Thanks, > > -- > Peter Xu > -- Sincerely yours, Mike.