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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28B09C433EF for ; Mon, 24 Jan 2022 21:39:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1456490AbiAXVjP (ORCPT ); Mon, 24 Jan 2022 16:39:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1453859AbiAXVbF (ORCPT ); Mon, 24 Jan 2022 16:31:05 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D81EC0AD1A2; Mon, 24 Jan 2022 12:19:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DB231B81229; Mon, 24 Jan 2022 20:19:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C797C340E5; Mon, 24 Jan 2022 20:19:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643055579; bh=AtSJyWWQBR0qTc4KjdnINqtOHj8XVN61e4NKDvYhRxE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gY8CsRtTLG6PbffeC/BTK9mihgRbOdGFGYgvkGa+2ZxcPwK8iZk2MUxe71XB8cmb6 g/BTD9xm/LZ6DR/Sd3pxJV8Zvzy+S09Sb7q128PtnJsrWQLQ5WkM/r0yKDx8+uqbHF 4UbVs/Yf6by+IyoeyIE5Gv56FlR3W9SsDU96Mn3U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maxim Mikityanskiy , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.15 198/846] bpf: Fix the test_task_vma selftest to support output shorter than 1 kB Date: Mon, 24 Jan 2022 19:35:15 +0100 Message-Id: <20220124184107.775121833@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Maxim Mikityanskiy [ Upstream commit da54ab14953c38d98cb3e34c564c06c3739394b2 ] The test for bpf_iter_task_vma assumes that the output will be longer than 1 kB, as the comment above the loop says. Due to this assumption, the loop becomes infinite if the output turns to be shorter than 1 kB. The return value of read_fd_into_buffer is 0 when the end of file was reached, and len isn't being increased any more. This commit adds a break on EOF to handle short output correctly. For the reference, this is the contents that I get when running test_progs under vmtest.sh, and it's shorter than 1 kB: 00400000-00401000 r--p 00000000 fe:00 25867 /root/bpf/test_progs 00401000-00674000 r-xp 00001000 fe:00 25867 /root/bpf/test_progs 00674000-0095f000 r--p 00274000 fe:00 25867 /root/bpf/test_progs 0095f000-00983000 r--p 0055e000 fe:00 25867 /root/bpf/test_progs 00983000-00a8a000 rw-p 00582000 fe:00 25867 /root/bpf/test_progs 00a8a000-0484e000 rw-p 00000000 00:00 0 7f6c64000000-7f6c64021000 rw-p 00000000 00:00 0 7f6c64021000-7f6c68000000 ---p 00000000 00:00 0 7f6c6ac8f000-7f6c6ac90000 r--s 00000000 00:0d 8032 anon_inode:bpf-map 7f6c6ac90000-7f6c6ac91000 ---p 00000000 00:00 0 7f6c6ac91000-7f6c6b491000 rw-p 00000000 00:00 0 7f6c6b491000-7f6c6b492000 r--s 00000000 00:0d 8032 anon_inode:bpf-map 7f6c6b492000-7f6c6b493000 rw-s 00000000 00:0d 8032 anon_inode:bpf-map 7ffc1e23d000-7ffc1e25e000 rw-p 00000000 00:00 0 7ffc1e3b8000-7ffc1e3bc000 r--p 00000000 00:00 0 7ffc1e3bc000-7ffc1e3bd000 r-xp 00000000 00:00 0 7fffffffe000-7ffffffff000 --xp 00000000 00:00 0 Fixes: e8168840e16c ("selftests/bpf: Add test for bpf_iter_task_vma") Signed-off-by: Maxim Mikityanskiy Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211130181811.594220-1-maximmi@nvidia.com Signed-off-by: Sasha Levin --- tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index 77ac24b191d4c..dc18e5ae0febc 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c @@ -1208,13 +1208,14 @@ static void test_task_vma(void) goto out; /* Read CMP_BUFFER_SIZE (1kB) from bpf_iter. Read in small chunks - * to trigger seq_file corner cases. The expected output is much - * longer than 1kB, so the while loop will terminate. + * to trigger seq_file corner cases. */ len = 0; while (len < CMP_BUFFER_SIZE) { err = read_fd_into_buffer(iter_fd, task_vma_output + len, min(read_size, CMP_BUFFER_SIZE - len)); + if (!err) + break; if (CHECK(err < 0, "read_iter_fd", "read_iter_fd failed\n")) goto out; len += err; -- 2.34.1