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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 C6B28C43381 for ; Thu, 28 Feb 2019 15:33:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EF1120C01 for ; Thu, 28 Feb 2019 15:33:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551368008; bh=6iG/VbiZpTdhS3dHGwtEBdHHNgkACqy6Z/1mLrJxjYE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=F78lvfv3X12ThNfIYpbEYRISKMBsHPiqhefmkj1hId4L2jGRyaYGfPj++kFVNDh8t ZaK84bFRy0fveM5qtcW0NgYrHyTWzHrImOBQhEVLgVkkQBXq5Vr/JEm7VLMQ8zsSfV vMF6LkWM0L1tybGjTM0tB5EX9AMzw0EABDYSs0gg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733074AbfB1PIn (ORCPT ); Thu, 28 Feb 2019 10:08:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:40958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733032AbfB1PIj (ORCPT ); Thu, 28 Feb 2019 10:08:39 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9DF94218AE; Thu, 28 Feb 2019 15:08:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551366518; bh=6iG/VbiZpTdhS3dHGwtEBdHHNgkACqy6Z/1mLrJxjYE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gqS9NHOdFShioEVbVL4gA4iNRQmCOexiluiQRTo4w/XZQZDfuMhoxl/7hnRsqjvaS eMfdBqM5JJlo0oQVsP8ZPV6vTZlA8g0gdrpuj9MV4sAfwwyDa5dAMw7eGJlUX5dyli 1zqx6mdSrmsePag6pQ9o//fJK0Dztx6tcSu5NMlQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiri Olsa , Daniel Borkmann , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 4.20 15/81] bpftool: Fix prog dump by tag Date: Thu, 28 Feb 2019 10:07:07 -0500 Message-Id: <20190228150813.10256-15-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190228150813.10256-1-sashal@kernel.org> References: <20190228150813.10256-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jiri Olsa [ Upstream commit 752bcf80f5549c9901b2e8bc77b2138de55b1026 ] Lance reported an issue with bpftool not being able to dump program if there are more programs loaded and you want to dump any but the first program, like: # bpftool prog 28: kprobe name trace_req_start tag 1dfc28ba8b3dd597 gpl loaded_at 2019-01-18T17:02:40+1100 uid 0 xlated 112B jited 109B memlock 4096B map_ids 13 29: kprobe name trace_req_compl tag 5b6a5ecc6030a683 gpl loaded_at 2019-01-18T17:02:40+1100 uid 0 xlated 928B jited 575B memlock 4096B map_ids 13,14 # bpftool prog dum jited tag 1dfc28ba8b3dd597 0: push %rbp 1: mov %rsp,%rbp ... # bpftool prog dum jited tag 5b6a5ecc6030a683 Error: can't get prog info (29): Bad address The problem is in the prog_fd_by_tag function not cleaning the struct bpf_prog_info before another request, so the previous program length is still in there and kernel assumes it needs to dump the program, which fails because there's no user pointer set. Moving the struct bpf_prog_info declaration into the loop, so it gets cleaned before each query. Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool") Reported-by: Lance Digby Signed-off-by: Jiri Olsa Reviewed-by: Quentin Monnet Acked-by: Jakub Kicinski Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- tools/bpf/bpftool/prog.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 69b01a6158bdd..91b9de5f4e17e 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -130,13 +130,14 @@ static void print_boot_time(__u64 nsecs, char *buf, unsigned int size) static int prog_fd_by_tag(unsigned char *tag) { - struct bpf_prog_info info = {}; - __u32 len = sizeof(info); unsigned int id = 0; int err; int fd; while (true) { + struct bpf_prog_info info = {}; + __u32 len = sizeof(info); + err = bpf_prog_get_next_id(id, &id); if (err) { p_err("%s", strerror(errno)); -- 2.19.1