From patchwork Wed Aug 17 14:33:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 9286055 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2AB1760574 for ; Wed, 17 Aug 2016 14:35:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1D348298F6 for ; Wed, 17 Aug 2016 14:35:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 120C1298FF; Wed, 17 Aug 2016 14:35:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 170A0298F6 for ; Wed, 17 Aug 2016 14:35:43 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ba1u5-0005h2-Vd; Wed, 17 Aug 2016 14:33:13 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ba1u5-0005gb-1S for xen-devel@lists.xenproject.org; Wed, 17 Aug 2016 14:33:13 +0000 Received: from [85.158.137.68] by server-13.bemta-3.messagelabs.com id 90/8D-06162-8A574B75; Wed, 17 Aug 2016 14:33:12 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupjkeJIrShJLcpLzFFi42JxWrrBXndF6ZZ wg0PyFt+3TGZyYPQ4/OEKSwBjFGtmXlJ+RQJrxs/N6gVNPBVb+5qZGhg/c3QxcnJICPhLbF/d wQJiswkoS/zs7GUDsUUE9CSaDjxnBLGZBbwkfqzoYQexhQXMJG4s/cYMYrMIqEq8m7WAtYuRg 4NXwFni0HEViJFyEueP/wQr4RRwkZiyaQMTiC0EVPJieSszhK0g0TH9GFicV0BQ4uTMJywQqy QkDr54wQwxh1vi9umpzBMY+WYhKZuFpGwBI9MqRo3i1KKy1CJdQ3O9pKLM9IyS3MTMHF1DA2O 93NTi4sT01JzEpGK95PzcTYzAcGIAgh2ML097HmKU5GBSEuWdOXFjuBBfUn5KZUZicUZ8UWlO avEhRhkODiUJXraSLeFCgkWp6akVaZk5wMCGSUtw8CiJ8HoVA6V5iwsSc4sz0yFSpxgVpcR5D 4IkBEASGaV5cG2waLrEKCslzMsIdIgQT0FqUW5mCar8K0ZxDkYlYd6rIFN4MvNK4Ka/AlrMBL SYlx9scUkiQkqqgTGmTiT3wTfGD/MrheZKWbcbvw/p9o//uIH5ZMolFm/mFVsZudZJFz0p71X 287AT5c1nuyc1VyJp/t7vaw6bvm963ZQiafqwPmP7d2FLL5a+fcFiNd+qf/ybu+bWxTfRt95y P1mnNC3Q2+hCrrLn/PjeI8sF5l/3i5y//7SUzswF/5aUaDcYdimxFGckGmoxFxUnAgCTNz0ao QIAAA== X-Env-Sender: prvs=030624cdf=wei.liu2@citrix.com X-Msg-Ref: server-15.tower-31.messagelabs.com!1471444389!52104959!2 X-Originating-IP: [66.165.176.63] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni42MyA9PiAzMDYwNDg=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 8.84; banners=-,-,- X-VirusChecked: Checked Received: (qmail 32925 invoked from network); 17 Aug 2016 14:33:11 -0000 Received: from smtp02.citrix.com (HELO SMTP02.CITRIX.COM) (66.165.176.63) by server-15.tower-31.messagelabs.com with RC4-SHA encrypted SMTP; 17 Aug 2016 14:33:11 -0000 X-IronPort-AV: E=Sophos;i="5.28,529,1464652800"; d="scan'208";a="380674984" From: Wei Liu To: Xen-devel Date: Wed, 17 Aug 2016 15:33:01 +0100 Message-ID: <1471444382-30409-2-git-send-email-wei.liu2@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1471444382-30409-1-git-send-email-wei.liu2@citrix.com> References: <1471444382-30409-1-git-send-email-wei.liu2@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 Cc: Wei Liu , Ian Jackson Subject: [Xen-devel] [PATCH 1/2] libs/gnttab: do not use alloca(3) X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP The semantics of alloca(3) is not very nice. If the stack overflows, program behaviour is undefined. Remove the use of alloca(3) and always use mmap. Signed-off-by: Wei Liu --- tools/libs/gnttab/linux.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/tools/libs/gnttab/linux.c b/tools/libs/gnttab/linux.c index 7b0fba4..535ce34 100644 --- a/tools/libs/gnttab/linux.c +++ b/tools/libs/gnttab/linux.c @@ -102,18 +102,12 @@ void *osdep_gnttab_grant_map(xengnttab_handle *xgt, if (flags & XENGNTTAB_GRANT_MAP_SINGLE_DOMAIN) domids_stride = 0; - if ( map_size <= PAGE_SIZE ) - map = alloca(sizeof(*map) + - (count - 1) * sizeof(struct ioctl_gntdev_map_grant_ref)); - else + map = mmap(NULL, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON | MAP_POPULATE, -1, 0); + if ( map == MAP_FAILED ) { - map = mmap(NULL, map_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANON | MAP_POPULATE, -1, 0); - if ( map == MAP_FAILED ) - { - GTERROR(xgt->logger, "mmap of map failed"); - return NULL; - } + GTERROR(xgt->logger, "mmap of map failed"); + return NULL; } for ( i = 0; i < count; i++ ) @@ -187,8 +181,7 @@ void *osdep_gnttab_grant_map(xengnttab_handle *xgt, } out: - if ( map_size > PAGE_SIZE ) - munmap(map, map_size); + munmap(map, map_size); return addr; }