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=-6.9 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 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 B8712C43603 for ; Thu, 12 Dec 2019 17:59:51 +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 8B9B22054F for ; Thu, 12 Dec 2019 17:59:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JbTQ1fMq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B9B22054F 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]:35140 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifSkg-00053w-0V for qemu-devel@archiver.kernel.org; Thu, 12 Dec 2019 12:59:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35784) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRWv-0007dq-Po for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRWu-0004bG-G5 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:33 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:57574 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ifRWu-0004a5-Bn for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168891; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DTKt64nmXmaYbPkNGoOTJq9dX/ls4SiUD1uWBfYfaA0=; b=JbTQ1fMqY6F/CNp4171PbwRAczis8lt9FkgKoHQbRfkf7IdG7iEzXPvhcBi3b+oos+sgQa TmVpGHKwq0ccFvjDPqfE+1ZvzybyCbnrIPjXbGmJwvS4ctNF1+qegpnZosGG0yj/ySh1bS FLd8b4YUMU29lG3Z752F+LM53nWZymI= 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-281-ZocUZrO0OA2mnCVl7jWiXQ-1; Thu, 12 Dec 2019 11:41:31 -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 CC26C801E7E for ; Thu, 12 Dec 2019 16:41:27 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id EE1D160BE1; Thu, 12 Dec 2019 16:41:26 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 088/104] virtiofsd: make lo_release() atomic Date: Thu, 12 Dec 2019 16:38:48 +0000 Message-Id: <20191212163904.159893-89-dgilbert@redhat.com> In-Reply-To: <20191212163904.159893-1-dgilbert@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: ZocUZrO0OA2mnCVl7jWiXQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Stefan Hajnoczi Hold the lock across both lo_map_get() and lo_map_remove() to prevent races between two FUSE_RELEASE requests. In this case I don't see a serious bug but it's safer to do things atomically. Signed-off-by: Stefan Hajnoczi --- tools/virtiofsd/passthrough_ll.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index fc79d5ac43..eadd568435 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1805,14 +1805,18 @@ static void lo_release(fuse_req_t req, fuse_ino_t i= no, struct fuse_file_info *fi) { struct lo_data *lo =3D lo_data(req); - int fd; + struct lo_map_elem *elem; + int fd =3D -1; =20 (void)ino; =20 - fd =3D lo_fi_fd(req, fi); - pthread_mutex_lock(&lo->mutex); - lo_map_remove(&lo->fd_map, fi->fh); + elem =3D lo_map_get(&lo->fd_map, fi->fh); + if (elem) { + fd =3D elem->fd; + elem =3D NULL; + lo_map_remove(&lo->fd_map, fi->fh); + } pthread_mutex_unlock(&lo->mutex); =20 close(fd); --=20 2.23.0