From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754073AbdC1BkE (ORCPT ); Mon, 27 Mar 2017 21:40:04 -0400 Received: from merlin.infradead.org ([205.233.59.134]:35524 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753953AbdC1BkC (ORCPT ); Mon, 27 Mar 2017 21:40:02 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Tommi Rantala , Alexander Shishkin , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 16/20] perf buildid: Do not assume that readlink() returns a null terminated string Date: Mon, 27 Mar 2017 22:39:11 -0300 Message-Id: <20170328013915.15236-17-acme@kernel.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170328013915.15236-1-acme@kernel.org> References: <20170328013915.15236-1-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tommi Rantala Valgrind was complaining: $ valgrind ./perf list >/dev/null ==11643== Memcheck, a memory error detector ==11643== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al. ==11643== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info ==11643== Command: ./perf list ==11643== ==11643== Conditional jump or move depends on uninitialised value(s) ==11643== at 0x4C30620: rindex (vg_replace_strmem.c:199) ==11643== by 0x49DAA9: build_id_cache__origname (build-id.c:198) ==11643== by 0x49E1C7: build_id_cache__valid_id (build-id.c:222) ==11643== by 0x49E1C7: build_id_cache__list_all (build-id.c:507) ==11643== by 0x4B9C8F: print_sdt_events (parse-events.c:2067) ==11643== by 0x4BB0B3: print_events (parse-events.c:2313) ==11643== by 0x439501: cmd_list (builtin-list.c:53) ==11643== by 0x497150: run_builtin (perf.c:359) ==11643== by 0x428CE0: handle_internal_command (perf.c:421) ==11643== by 0x428CE0: run_argv (perf.c:467) ==11643== by 0x428CE0: main (perf.c:614) [...] Additionally, a zero length result from readlink() is not very interesting. Signed-off-by: Tommi Rantala Cc: Alexander Shishkin Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170322130624.21881-3-tommi.t.rantala@nokia.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/build-id.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index 234859f756c4..33af67530d30 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -182,13 +182,17 @@ char *build_id_cache__origname(const char *sbuild_id) char buf[PATH_MAX]; char *ret = NULL, *p; size_t offs = 5; /* == strlen("../..") */ + ssize_t len; linkname = build_id_cache__linkname(sbuild_id, NULL, 0); if (!linkname) return NULL; - if (readlink(linkname, buf, PATH_MAX) < 0) + len = readlink(linkname, buf, sizeof(buf) - 1); + if (len <= 0) goto out; + buf[len] = '\0'; + /* The link should be "../../" */ p = strrchr(buf, '/'); /* Cut off the "/" */ if (p && (p > buf + offs)) { -- 2.9.3