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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6D2FCC433DF for ; Mon, 10 Aug 2020 15:40:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57C8620825 for ; Mon, 10 Aug 2020 15:40:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729131AbgHJPke (ORCPT ); Mon, 10 Aug 2020 11:40:34 -0400 Received: from foss.arm.com ([217.140.110.172]:57722 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728755AbgHJPk3 (ORCPT ); Mon, 10 Aug 2020 11:40:29 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 97B201063; Mon, 10 Aug 2020 08:40:28 -0700 (PDT) Received: from net-arm-thunderx2-02.shanghai.arm.com (net-arm-thunderx2-02.shanghai.arm.com [10.169.210.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BC74B3F575; Mon, 10 Aug 2020 08:40:25 -0700 (PDT) From: Jianlin Lv To: bpf@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, yhs@fb.com, Jianlin.Lv@arm.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf-next v2] bpf: fix segmentation fault of test_progs Date: Mon, 10 Aug 2020 23:39:40 +0800 Message-Id: <20200810153940.125508-1-Jianlin.Lv@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200807172016.150952-1-Jianlin.Lv@arm.com> References: <20200807172016.150952-1-Jianlin.Lv@arm.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- v2: - Update commit messages - Create 4 pages of anonymous mapping that serve the subsequent mmap() --- tools/testing/selftests/bpf/prog_tests/mmap.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/mmap.c b/tools/testing/selftests/bpf/prog_tests/mmap.c index 43d0b5578f46..9c3c5c0f068f 100644 --- a/tools/testing/selftests/bpf/prog_tests/mmap.c +++ b/tools/testing/selftests/bpf/prog_tests/mmap.c @@ -21,7 +21,7 @@ void test_mmap(void) const long page_size = sysconf(_SC_PAGE_SIZE); int err, duration = 0, i, data_map_fd, data_map_id, tmp_fd, rdmap_fd; struct bpf_map *data_map, *bss_map; - void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp1, *tmp2; + void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp0, *tmp1, *tmp2; struct test_mmap__bss *bss_data; struct bpf_map_info map_info; __u32 map_info_sz = sizeof(map_info); @@ -183,16 +183,23 @@ void test_mmap(void) /* check some more advanced mmap() manipulations */ + tmp0 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_ANONYMOUS, + -1, 0); + if (CHECK(tmp0 == MAP_FAILED, "adv_mmap0", "errno %d\n", errno)) + goto cleanup; + /* map all but last page: pages 1-3 mapped */ - tmp1 = mmap(NULL, 3 * page_size, PROT_READ, MAP_SHARED, + tmp1 = mmap(tmp0, 3 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED, data_map_fd, 0); - if (CHECK(tmp1 == MAP_FAILED, "adv_mmap1", "errno %d\n", errno)) + if (CHECK(tmp0 != tmp1, "adv_mmap1", "tmp0: %p, tmp1: %p\n", tmp0, tmp1)) { + munmap(tmp0, 4 * page_size); goto cleanup; + } /* unmap second page: pages 1, 3 mapped */ err = munmap(tmp1 + page_size, page_size); if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) { - munmap(tmp1, map_sz); + munmap(tmp1, 4 * page_size); goto cleanup; } @@ -201,7 +208,7 @@ void test_mmap(void) MAP_SHARED | MAP_FIXED, data_map_fd, 0); if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) { munmap(tmp1, page_size); - munmap(tmp1 + 2*page_size, page_size); + munmap(tmp1 + 2*page_size, 2 * page_size); goto cleanup; } CHECK(tmp1 + page_size != tmp2, "adv_mmap4", @@ -211,7 +218,7 @@ void test_mmap(void) tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED, data_map_fd, 0); if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) { - munmap(tmp1, 3 * page_size); /* unmap page 1 */ + munmap(tmp1, 4 * page_size); /* unmap page 1 */ goto cleanup; } CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2); -- 2.17.1