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 88222C433EF for ; Wed, 16 Feb 2022 19:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238343AbiBPTvi (ORCPT ); Wed, 16 Feb 2022 14:51:38 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:48808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238301AbiBPTvg (ORCPT ); Wed, 16 Feb 2022 14:51:36 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF7122C3 for ; Wed, 16 Feb 2022 11:51:22 -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 sin.source.kernel.org (Postfix) with ESMTPS id 5B781CE28BD for ; Wed, 16 Feb 2022 19:51:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A2B1C004E1; Wed, 16 Feb 2022 19:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645041079; bh=/kAffq5at/nvUe/Zf5JLZv0VEVC28bcRZ0RwVa1PKhY=; h=Date:From:To:Cc:Subject:From; b=IE9qtlys/BxiETwkUSn29269tmBrWHIPZ8XaXkUOMYvV0Y5p4MDDoc4SY+zpvaDc3 j6PnArOxHNauKD7Cylr2fTwkawGbZ867vnF6csPhgX4JJ0CG4jQjq/qERq3yMzvV0u zQJGKzioDQt82vz3E5pPdemzwLHPjRQthxqaZs/Kgd7BW8m5WsBT0ksJKl+c/V32hz tlvmPu3jnNHCEnQPWN+mlwlSob8LeLPQfke5sLEouistHo8pxSMJk+7yuEZsHMfr73 ZmxqT7LLO8CuYwUELtvEwOvk50GQY7x0WrzHXQ0hh2uLyHSz9loPcsscPF8rzb1Lw0 DV/834Hag/Q4g== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 950A2400FE; Wed, 16 Feb 2022 16:51:17 -0300 (-03) Date: Wed, 16 Feb 2022 16:51:17 -0300 From: Arnaldo Carvalho de Melo To: Wang ShaoBo Cc: Adrian Hunter , Ian Rogers , Jiri Olsa , Namhyung Kim , Linux Kernel Mailing List Subject: [PATCH 1/1] perf bpf: Defer freeing string after possible strlen() on it Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org FYI: I'm carrying this on my tree: --- This was detected by the gcc in Fedora Rawhide's gcc: 50 11.01 fedora:rawhide : FAIL gcc version 12.0.1 20220205 (Red Hat 12.0.1-0) (GCC) inlined from 'bpf__config_obj' at util/bpf-loader.c:1242:9: util/bpf-loader.c:1225:34: error: pointer 'map_opt' may be used after 'free' [-Werror=use-after-free] 1225 | *key_scan_pos += strlen(map_opt); | ^~~~~~~~~~~~~~~ util/bpf-loader.c:1223:9: note: call to 'free' here 1223 | free(map_name); | ^~~~~~~~~~~~~~ cc1: all warnings being treated as errors So do the calculations on the pointer before freeing it. Fixes: 04f9bf2bac72480c ("perf bpf-loader: Add missing '*' for key_scan_pos") Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang ShaoBo Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 7ecfaac7536a1b1b..16ec605a9fe46a64 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -1220,9 +1220,10 @@ bpf__obj_config_map(struct bpf_object *obj, pr_debug("ERROR: Invalid map config option '%s'\n", map_opt); err = -BPF_LOADER_ERRNO__OBJCONF_MAP_OPT; out: - free(map_name); if (!err) *key_scan_pos += strlen(map_opt); + + free(map_name); return err; } -- 2.34.1