From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752384AbbIFHPu (ORCPT ); Sun, 6 Sep 2015 03:15:50 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:7331 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750888AbbIFHOj (ORCPT ); Sun, 6 Sep 2015 03:14:39 -0400 From: Wang Nan To: , , , CC: , , , , , , , , , , , Subject: [PATCH 01/27] perf tools: Don't write to evsel if parser doesn't collect evsel Date: Sun, 6 Sep 2015 07:13:17 +0000 Message-ID: <1441523623-152703-2-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> References: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If parse_events__scanner() collects no entry, perf_evlist__last(evlist) is invalid. Although it shouldn't happen at this point, before calling perf_evlist__last(), we should ensure the list is not empty for safety reason. There are 3 places need this checking: 1. Before setting cmdline_group_boundary; 2. Before __perf_evlist__set_leader(); 3. In foreach_evsel_in_last_glob. Signed-off-by: Wang Nan Reviewed-by: Masami Hiramatsu Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Jiri Olsa Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: https://lkml.kernel.org/n/1441176553-116129-1-git-send-email-wangnan0@huawei.com [wangnan: Enforce the assumption that parser never collect empty list] --- tools/perf/util/parse-events.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 3840176..07ce501 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -793,6 +793,11 @@ void parse_events__set_leader(char *name, struct list_head *list) { struct perf_evsel *leader; + if (list_empty(list)) { + WARN_ONCE(true, "WARNING: failed to set leader: empty list"); + return; + } + __perf_evlist__set_leader(list); leader = list_entry(list->next, struct perf_evsel, node); leader->group_name = name ? strdup(name) : NULL; @@ -1143,10 +1148,16 @@ int parse_events(struct perf_evlist *evlist, const char *str, int entries = data.idx - evlist->nr_entries; struct perf_evsel *last; + if (list_empty(&data.list)) { + WARN_ONCE(true, "WARNING: event parser found nothing"); + return -1; + } + + last = list_entry(data.list.prev, struct perf_evsel, node); + last->cmdline_group_boundary = true; + perf_evlist__splice_list_tail(evlist, &data.list, entries); evlist->nr_groups += data.nr_groups; - last = perf_evlist__last(evlist); - last->cmdline_group_boundary = true; return 0; } @@ -1252,7 +1263,13 @@ foreach_evsel_in_last_glob(struct perf_evlist *evlist, struct perf_evsel *last = NULL; int err; - if (evlist->nr_entries > 0) + /* + * Don't return when list_empty, give func a chance to report + * error when it found last == NULL. + * + * So no need to WARN here, let *func do this. + */ + if (!list_empty(&evlist->entries)) last = perf_evlist__last(evlist); do { -- 2.1.0