From patchwork Wed Apr 10 06:54:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Magnus Karlsson X-Patchwork-Id: 1083196 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44fFJf4z42z9s8m for ; Wed, 10 Apr 2019 16:54:42 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728672AbfDJGyl (ORCPT ); Wed, 10 Apr 2019 02:54:41 -0400 Received: from mga02.intel.com ([134.134.136.20]:21903 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726894AbfDJGyl (ORCPT ); Wed, 10 Apr 2019 02:54:41 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Apr 2019 23:54:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,332,1549958400"; d="scan'208";a="290252677" Received: from mkarlsso-mobl.ger.corp.intel.com (HELO VM.isw.intel.com) ([10.103.211.40]) by orsmga004.jf.intel.com with ESMTP; 09 Apr 2019 23:54:38 -0700 From: Magnus Karlsson To: magnus.karlsson@intel.com, bjorn.topel@intel.com, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH bpf-next v2] libbpf: fix crash in XDP socket part with new larger BPF_LOG_BUF_SIZE Date: Wed, 10 Apr 2019 08:54:16 +0200 Message-Id: <1554879256-30587-1-git-send-email-magnus.karlsson@intel.com> X-Mailer: git-send-email 2.7.4 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-Id: netdev.vger.kernel.org In commit da11b417583e ("libbpf: teach libbpf about log_level bit 2"), the BPF_LOG_BUF_SIZE was increased to 16M. The XDP socket part of libbpf allocated the log_buf on the stack, but for the new 16M buffer size this is not going to work. Change the code so it uses a 16K buffer instead. Signed-off-by: Magnus Karlsson Acked-by: Yonghong Song --- v2: simplified code as suggested by Daniel Borkmann tools/lib/bpf/xsk.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) -- 2.7.4 diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 8d0078b..557ef8d 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -259,7 +259,8 @@ int xsk_umem__create(struct xsk_umem **umem_ptr, void *umem_area, __u64 size, static int xsk_load_xdp_prog(struct xsk_socket *xsk) { - char bpf_log_buf[BPF_LOG_BUF_SIZE]; + static const int log_buf_size = 16 * 1024; + char log_buf[log_buf_size]; int err, prog_fd; /* This is the C-program: @@ -308,10 +309,10 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); prog_fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog, insns_cnt, - "LGPL-2.1 or BSD-2-Clause", 0, bpf_log_buf, - BPF_LOG_BUF_SIZE); + "LGPL-2.1 or BSD-2-Clause", 0, log_buf, + log_buf_size); if (prog_fd < 0) { - pr_warning("BPF log buffer:\n%s", bpf_log_buf); + pr_warning("BPF log buffer:\n%s", log_buf); return prog_fd; }