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=-8.4 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,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 0A49BC33CB1 for ; Thu, 16 Jan 2020 12:25:28 +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 CBC4320748 for ; Thu, 16 Jan 2020 12:25:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZhH5an9B" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBC4320748 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]:40914 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is4DH-0004sP-1G for qemu-devel@archiver.kernel.org; Thu, 16 Jan 2020 07:25:27 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:33763) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is4CF-0004An-Re for qemu-devel@nongnu.org; Thu, 16 Jan 2020 07:24:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1is4CC-0000aw-AP for qemu-devel@nongnu.org; Thu, 16 Jan 2020 07:24:23 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:25487 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1is4CC-0000ai-6P for qemu-devel@nongnu.org; Thu, 16 Jan 2020 07:24:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579177459; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3SvJn6kZh3SeUiqsGNfaKamBOIhw3r8vEAqHDJ+yG9E=; b=ZhH5an9BAS6jyduGdb2UFMP1u0O0gCIaD243Zlf0xq31t4hlolq+NzhH72g8jbVzR2Pkct 4mV7LZRVovPnbdIM0szHCEwutI3hOhf6qFl0e+qpINprmWSN0fi4Y1+BKwz1sAAYi9neii XyIP/9zwMLlQvV9Xj2c0yx98fgFiAIA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-421-kGC95aI3PSWmDtzcH6qmkw-1; Thu, 16 Jan 2020 07:24:18 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 13830107ACC5; Thu, 16 Jan 2020 12:24:17 +0000 (UTC) Received: from work-vm (unknown [10.36.118.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8E1D860E3E; Thu, 16 Jan 2020 12:24:13 +0000 (UTC) Date: Thu, 16 Jan 2020 12:24:11 +0000 From: "Dr. David Alan Gilbert" To: Masayoshi Mizuma Subject: Re: [PATCH 101/104] virtiofsd: prevent FUSE_INIT/FUSE_DESTROY races Message-ID: <20200116122411.GD3108@work-vm> References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-102-dgilbert@redhat.com> <20200115230522.hslcfqplmzthglvv@gabell> MIME-Version: 1.0 In-Reply-To: <20200115230522.hslcfqplmzthglvv@gabell> User-Agent: Mutt/1.13.0 (2019-11-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: kGC95aI3PSWmDtzcH6qmkw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Masayoshi Mizuma (msys.mizuma@gmail.com) wrote: > On Thu, Dec 12, 2019 at 04:39:01PM +0000, Dr. David Alan Gilbert (git) wr= ote: > > From: Stefan Hajnoczi > >=20 > > When running with multiple threads it can be tricky to handle > > FUSE_INIT/FUSE_DESTROY in parallel with other request types or in > > parallel with themselves. Serialize FUSE_INIT and FUSE_DESTROY so that > > malicious clients cannot trigger race conditions. > >=20 > > Signed-off-by: Stefan Hajnoczi > > --- > > tools/virtiofsd/fuse_i.h | 1 + > > tools/virtiofsd/fuse_lowlevel.c | 18 ++++++++++++++++++ > > 2 files changed, 19 insertions(+) > >=20 > > diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h > > index d0679508cd..8a4a05b319 100644 > > --- a/tools/virtiofsd/fuse_i.h > > +++ b/tools/virtiofsd/fuse_i.h > > @@ -61,6 +61,7 @@ struct fuse_session { > > struct fuse_req list; > > struct fuse_req interrupts; > > pthread_mutex_t lock; > > + pthread_rwlock_t init_rwlock; > > int got_destroy; > > int broken_splice_nonblock; > > uint64_t notify_ctr; > > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_low= level.c > > index 10f478b00c..9f01c05e3e 100644 > > --- a/tools/virtiofsd/fuse_lowlevel.c > > +++ b/tools/virtiofsd/fuse_lowlevel.c > > @@ -2431,6 +2431,19 @@ void fuse_session_process_buf_int(struct fuse_se= ssion *se, > > req->ctx.pid =3D in->pid; > > req->ch =3D ch ? fuse_chan_get(ch) : NULL; > > =20 > > + /* > > + * INIT and DESTROY requests are serialized, all other request typ= es > > + * run in parallel. This prevents races between FUSE_INIT and ord= inary > > + * requests, FUSE_INIT and FUSE_INIT, FUSE_INIT and FUSE_DESTROY, = and > > + * FUSE_DESTROY and FUSE_DESTROY. > > + */ > > + if (in->opcode =3D=3D FUSE_INIT || in->opcode =3D=3D CUSE_INIT || > > + in->opcode =3D=3D FUSE_DESTROY) { > > + pthread_rwlock_wrlock(&se->init_rwlock); > > + } else { > > + pthread_rwlock_rdlock(&se->init_rwlock); > > + } > > + > > err =3D EIO; > > if (!se->got_init) { > > enum fuse_opcode expected; > > @@ -2488,10 +2501,13 @@ void fuse_session_process_buf_int(struct fuse_s= ession *se, > > } else { > > fuse_ll_ops[in->opcode].func(req, in->nodeid, &iter); > > } > > + > > + pthread_rwlock_unlock(&se->init_rwlock); > > return; > > =20 > > reply_err: > > fuse_reply_err(req, err); > > + pthread_rwlock_unlock(&se->init_rwlock); > > } > > =20 > > #define LL_OPTION(n, o, v) \ > > @@ -2538,6 +2554,7 @@ void fuse_session_destroy(struct fuse_session *se= ) > > se->op.destroy(se->userdata); > > } > > } > > + pthread_rwlock_destroy(&se->init_rwlock); > > pthread_mutex_destroy(&se->lock); > > free(se->cuse_data); > > if (se->fd !=3D -1) { > > @@ -2631,6 +2648,7 @@ struct fuse_session *fuse_session_new(struct fuse= _args *args, > > list_init_req(&se->list); > > list_init_req(&se->interrupts); > > fuse_mutex_init(&se->lock); > > + pthread_rwlock_init(&se->init_rwlock, NULL); > > =20 > > memcpy(&se->op, op, op_size); > > se->owner =3D getuid(); >=20 > Looks good to me. >=20 > Reviewed-by: Masayoshi Mizuma Thanks > > --=20 > > 2.23.0 > >=20 > >=20 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK