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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 8FD2BC433DF for ; Thu, 14 May 2020 12:30:31 +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 65C7E206DA for ; Thu, 14 May 2020 12:30:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="O4UK8kiQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65C7E206DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.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:In-Reply-To:References: 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: List-Owner; bh=5FnEoBx9RBKIQBdZn5gLYWmHn4n4ZRneNxSz0NGbXO8=; b=O4UK8kiQuGKAAn /0X02zHD5LCNrYFzQl3EfNJFnds2PrPlkE8cM/aSIK6IdnkOv8jT3zEe7Aq/5laaKKwfXlyd3vUzg MYBUtlKkNAkGq25vUI920Wjnabi5YTL8DxjNZhuz3Ycz6vf14Fq/M/HVZW8kKiZ0BEToCf5DBTJsj leN5GO7noXuMqKJkFRLwvXsO+s0iPeAyleff+2sGBP00JZAajfP2gw/3Xm5V0x24qXdhpq9EanwPj OWn7ymWeUP/LyG2Om+nNpgx+XafKfH/WwHs5dBDMoUzGpmCzv9wafmd9RfzejGmR7Sz11pDvwpKQT PLz2N5lIgFNpQ1wsg/Zg==; 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 1jZD0N-0000pC-T0; Thu, 14 May 2020 12:30:27 +0000 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jZD0K-0000Wo-C6 for linux-nvme@lists.infradead.org; Thu, 14 May 2020 12:30:26 +0000 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-254-IsdhEyj2MaapF7FHDwegSA-1; Thu, 14 May 2020 13:30:18 +0100 X-MC-Unique: IsdhEyj2MaapF7FHDwegSA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 14 May 2020 13:30:17 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 14 May 2020 13:30:17 +0100 From: David Laight To: 'Marcelo Ricardo Leitner' , 'Christoph Hellwig' Subject: RE: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr Thread-Topic: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr Thread-Index: AQHWKVDpRRlTTX4YZEat3HB6AYvqqainVRxwgAAtMyA= Date: Thu, 14 May 2020 12:30:17 +0000 Message-ID: References: <20200513062649.2100053-1-hch@lst.de> <20200513062649.2100053-33-hch@lst.de> <20200513180302.GC2491@localhost.localdomain> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200514_053024_699752_9704BC7F X-CRM114-Status: GOOD ( 14.18 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: 'Eric Dumazet' , "'linux-nvme@lists.infradead.org'" , "'linux-sctp@vger.kernel.org'" , "'target-devel@vger.kernel.org'" , "'linux-afs@lists.infradead.org'" , "'drbd-dev@lists.linbit.com'" , "'linux-cifs@vger.kernel.org'" , "'rds-devel@oss.oracle.com'" , "'linux-rdma@vger.kernel.org'" , "'cluster-devel@redhat.com'" , 'Alexey Kuznetsov' , "'linux-block@vger.kernel.org'" , 'Jakub Kicinski' , "'ceph-devel@vger.kernel.org'" , "'linux-nfs@vger.kernel.org'" , 'Neil Horman' , 'Hideaki YOSHIFUJI' , "'netdev@vger.kernel.org'" , 'Vlad Yasevich' , "'linux-kernel@vger.kernel.org'" , 'Jon Maloy' , 'Ying Xue' , "'David S. Miller'" , "'ocfs2-devel@oss.oracle.com'" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org From: David Laight > Sent: 14 May 2020 10:51 > From: Marcelo Ricardo Leitner > > Sent: 13 May 2020 19:03 > > > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > > space without going through a fake uaccess. > > > > Same comment as on the other dlm/sctp patch. > > Wouldn't it be best to write sctp_[gs]etsockotp() that > use a kernel buffer and then implement the user-space > calls using a wrapper that does the copies to an on-stack > (or malloced if big) buffer. Actually looking at __sys_setsockopt() it calls BPF_CGROUP_RUN_PROG_SETSOCKOPT() which (by the look of it) can copy the user buffer into malloc()ed memory and cause set_fs(KERNEL_DS) be called. The only way to get rid of that set_fs() is to always have the buffer in kernel memory when the underlying setsockopt() code is called. The comment above __sys_[sg]etsockopt() about not knowing the length is just wrong. It probably applied to getsockopt() in the dim and distant past before it was made read-update. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme