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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 350E0C433E0 for ; Tue, 11 Aug 2020 13:20:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A86F2076C for ; Tue, 11 Aug 2020 13:20:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728550AbgHKNUM (ORCPT ); Tue, 11 Aug 2020 09:20:12 -0400 Received: from www62.your-server.de ([213.133.104.62]:59496 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728516AbgHKNUM (ORCPT ); Tue, 11 Aug 2020 09:20:12 -0400 Received: from sslproxy05.your-server.de ([78.46.172.2]) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1k5UC8-0004uL-KX; Tue, 11 Aug 2020 15:20:00 +0200 Received: from [178.196.57.75] (helo=pc-9.home) by sslproxy05.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k5UC8-000Bp1-Dr; Tue, 11 Aug 2020 15:20:00 +0200 Subject: Re: [PATCH bpf-next v2] bpf: fix segmentation fault of test_progs To: Jianlin Lv , bpf@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, ast@kernel.org, yhs@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <20200807172016.150952-1-Jianlin.Lv@arm.com> <20200810153940.125508-1-Jianlin.Lv@arm.com> From: Daniel Borkmann Message-ID: <066bc6b8-8e08-e473-b454-4544e99ad7e0@iogearbox.net> Date: Tue, 11 Aug 2020 15:19:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200810153940.125508-1-Jianlin.Lv@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.4/25900/Mon Aug 10 14:44:29 2020) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 8/10/20 5:39 PM, Jianlin Lv wrote: > test_progs reports the segmentation fault as below > > $ sudo ./test_progs -t mmap --verbose > test_mmap:PASS:skel_open_and_load 0 nsec > ...... > test_mmap:PASS:adv_mmap1 0 nsec > test_mmap:PASS:adv_mmap2 0 nsec > test_mmap:PASS:adv_mmap3 0 nsec > test_mmap:PASS:adv_mmap4 0 nsec > Segmentation fault > > This issue was triggered because mmap() and munmap() used inconsistent > length parameters; mmap() creates a new mapping of 3*page_size, but the > length parameter set in the subsequent re-map and munmap() functions is > 4*page_size; this leads to the destruction of the process space. > > To fix this issue, first create 4 pages of anonymous mapping,then do all > the mmap() with MAP_FIXED. > > Another issue is that when unmap the second page fails, the length > parameter to delete tmp1 mappings should be 4*page_size. > > Signed-off-by: Jianlin Lv Applied, thanks!