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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B3F8C433F5 for ; Mon, 11 Oct 2021 14:04:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1ECE66134F for ; Mon, 11 Oct 2021 14:04:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238659AbhJKOGn (ORCPT ); Mon, 11 Oct 2021 10:06:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:57034 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241344AbhJKOEm (ORCPT ); Mon, 11 Oct 2021 10:04:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5E7A3611F0; Mon, 11 Oct 2021 13:59:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633960760; bh=g6Xv7qVJhaf59HaVsfE/cRahpHghZMwfXaloG5jccZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lSH/+QhMuXpWA2y9nRUp9FhXLBTwucDlSl0wjF9HOby1ORUAeYv2t1uqU+JqBIm9r 4fI8RynuHjEs+ojwS7qajsMdRoV+TNgy1CrQQ/Z3T5AFdQu8aLV8mKXZrTpUtys0GC 2GyHhJWh92qx4sUZUjXACzpCV6wN+VcWaoCt8NAQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kumar Kartikeya Dwivedi , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.14 066/151] libbpf: Fix segfault in light skeleton for objects without BTF Date: Mon, 11 Oct 2021 15:45:38 +0200 Message-Id: <20211011134519.983304176@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211011134517.833565002@linuxfoundation.org> References: <20211011134517.833565002@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: Kumar Kartikeya Dwivedi [ Upstream commit 4729445b47efebf089da4ccbcd1b116ffa2ad4af ] When fed an empty BPF object, bpftool gen skeleton -L crashes at btf__set_fd() since it assumes presence of obj->btf, however for the sequence below clang adds no .BTF section (hence no BTF). Reproducer: $ touch a.bpf.c $ clang -O2 -g -target bpf -c a.bpf.c $ bpftool gen skeleton -L a.bpf.o /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ /* THIS FILE IS AUTOGENERATED! */ struct a_bpf { struct bpf_loader_ctx ctx; Segmentation fault (core dumped) The same occurs for files compiled without BTF info, i.e. without clang's -g flag. Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.) Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210930061634.1840768-1-memxor@gmail.com Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d27e017ebfbe..f1bc09e606cd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -8115,7 +8115,8 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr) if (obj->gen_loader) { /* reset FDs */ - btf__set_fd(obj->btf, -1); + if (obj->btf) + btf__set_fd(obj->btf, -1); for (i = 0; i < obj->nr_maps; i++) obj->maps[i].fd = -1; if (!err) -- 2.33.0