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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2711FC4360C for ; Fri, 4 Oct 2019 19:02:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 01DC62084D for ; Fri, 4 Oct 2019 19:02:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01DC62084D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51288 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iGSq7-0005EB-Ux for qemu-devel@archiver.kernel.org; Fri, 04 Oct 2019 15:02:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36957) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iGSiX-0000V3-P8 for qemu-devel@nongnu.org; Fri, 04 Oct 2019 14:54:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iGSiS-00020c-JX for qemu-devel@nongnu.org; Fri, 04 Oct 2019 14:54:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51078) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iGSiQ-0001tt-MJ for qemu-devel@nongnu.org; Fri, 04 Oct 2019 14:54:11 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 96DBE8A1CA7; Fri, 4 Oct 2019 18:54:06 +0000 (UTC) Received: from work-vm (unknown [10.36.118.29]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 577AD1001DC2; Fri, 4 Oct 2019 18:54:03 +0000 (UTC) Date: Fri, 4 Oct 2019 19:54:00 +0100 From: "Dr. David Alan Gilbert" To: Misono Tomohiro Subject: Re: [Virtio-fs] [PATCH] virtiofsd: Add pread64() to seccomp list for posix_fallocate() Message-ID: <20191004185400.GH2772@work-vm> References: <20191004110759.32665-1-misono.tomohiro@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191004110759.32665-1-misono.tomohiro@jp.fujitsu.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.69]); Fri, 04 Oct 2019 18:54:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Misono Tomohiro (misono.tomohiro@jp.fujitsu.com) wrote: > I test virtiofs with NFS 4.0 as backend and notice that fallocate > causes system hang (kernel: 5.4-rc1, qemu: virtio-fs-dev branch): > $ mount -t virtiofs myfs /mnt > $ dd if=/dev/urandom bs=1000 seek=1 count=1 of=/mnt/file > $ fallocate -l 2000 /mnt/file # system hang > > This is because: > 1. virtiofs supports fallocate syscall while NFS 4.0 does not. > 2. virtiofsd uses posix_fallocate() and it fallbacks to pread64()/ > pwrite64() sequence to reserve blocks if fallocate syscall is > not available. > 3. pread64() syscall is prohibited by seccomp and virtiofsd thread > is killed by SIGSYS. > > So, just add pread64() to seccomp white list to fix this problem. > > Signed-off-by: Misono Tomohiro Thanks, I've squashed this into our seccomp commit. (It'll be a little while before I push it out, I need to finish a tidyup I'm doing). Dave > --- > contrib/virtiofsd/seccomp.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/contrib/virtiofsd/seccomp.c b/contrib/virtiofsd/seccomp.c > index 93b679271d..88b61bca42 100644 > --- a/contrib/virtiofsd/seccomp.c > +++ b/contrib/virtiofsd/seccomp.c > @@ -61,6 +61,7 @@ static const int syscall_whitelist[] = { > SCMP_SYS(ppoll), > SCMP_SYS(prctl), /* TODO restrict to just PR_SET_NAME? */ > SCMP_SYS(preadv), > + SCMP_SYS(pread64), > SCMP_SYS(pwritev), > SCMP_SYS(pwrite64), > SCMP_SYS(read), > -- > 2.21.0 > > _______________________________________________ > Virtio-fs mailing list > Virtio-fs@redhat.com > https://www.redhat.com/mailman/listinfo/virtio-fs -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK