linux-kernel - [PATCH 3/3] perf, stat: Fix free memory access / memory leaks in metrics

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Date:   Mon, 23 Sep 2019 16:33:39 -0700
From:   Andi Kleen <andi@...stfloor.org>
To:     acme@...nel.org
Cc:     jolsa@...nel.org, linux-kernel@...r.kernel.org,
        Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 3/3] perf, stat: Fix free memory access / memory leaks in metrics

From: Andi Kleen <ak@...ux.intel.com>

Make sure to not free the name passed in by the caller, but free
all the allocated ids when parsing expressions.

The loop at the end knows that the first entry shouldn't be freed,
so make sure the caller name is the first entry.

Fixes

% perf stat -M IpB,IpCall,IpTB,IPC,Retiring_SMT,Frontend_Bound_SMT,Kernel_Utilization,CPU_Utilization --metric-only -a -I 1000 sleep 2

valgrind:
     1.009943231 ==21527== Invalid read of size 1
==21527==    at 0x483CB74: strcmp (vg_replace_strmem.c:849)
==21527==    by 0x582CF8: collect_all_aliases (stat-display.c:554)
==21527==    by 0x582EB3: collect_data (stat-display.c:577)
==21527==    by 0x583A32: print_counter_aggr (stat-display.c:806)
==21527==    by 0x584FAD: perf_evlist__print_counters (stat-display.c:1200)
==21527==    by 0x45133A: print_counters (builtin-stat.c:655)
==21527==    by 0x450629: process_interval (builtin-stat.c:353)
==21527==    by 0x450FBD: __run_perf_stat (builtin-stat.c:564)
==21527==    by 0x451285: run_perf_stat (builtin-stat.c:636)
==21527==    by 0x454619: cmd_stat (builtin-stat.c:1966)
==21527==    by 0x4D557D: run_builtin (perf.c:310)
==21527==    by 0x4D57EA: handle_internal_command (perf.c:362)
==21527==  Address 0x12826cd0 is 0 bytes inside a block of size 25 free'd
==21527==    at 0x4839A0C: free (vg_replace_malloc.c:540)
==21527==    by 0x627041: __zfree (zalloc.c:13)
==21527==    by 0x57F66A: generic_metric (stat-shadow.c:814)
==21527==    by 0x580B21: perf_stat__print_shadow_stats (stat-shadow.c:1057)
==21527==    by 0x58418E: print_metric_headers (stat-display.c:943)
==21527==    by 0x5844BC: print_interval (stat-display.c:1004)
==21527==    by 0x584DEB: perf_evlist__print_counters (stat-display.c:1172)
==21527==    by 0x45133A: print_counters (builtin-stat.c:655)
==21527==    by 0x450629: process_interval (builtin-stat.c:353)
==21527==    by 0x450FBD: __run_perf_stat (builtin-stat.c:564)
==21527==    by 0x451285: run_perf_stat (builtin-stat.c:636)
==21527==    by 0x454619: cmd_stat (builtin-stat.c:1966)
==21527==  Block was alloc'd at
==21527==    at 0x483880B: malloc (vg_replace_malloc.c:309)
==21527==    by 0x51677DE: strdup (in /usr/lib64/libc-2.29.so)
==21527==    by 0x506457: parse_events_name (parse-events.c:1754)
==21527==    by 0x5550BB: parse_events_parse (parse-events.y:214)
==21527==    by 0x50694D: parse_events__scanner (parse-events.c:1887)
==21527==    by 0x506AEF: parse_events (parse-events.c:1927)
==21527==    by 0x521D8B: metricgroup__parse_groups (metricgroup.c:527)
==21527==    by 0x45156F: parse_metric_groups (builtin-stat.c:721)
==21527==    by 0x6228A9: get_value (parse-options.c:243)
==21527==    by 0x62363F: parse_short_opt (parse-options.c:348)
==21527==    by 0x62363F: parse_options_step (parse-options.c:536)
==21527==    by 0x62363F: parse_options_subcommand (parse-options.c:651)
==21527==    by 0x453C1D: cmd_stat (builtin-stat.c:1718)
==21527==    by 0x4D557D: run_builtin (perf.c:310)

and also a leak report.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 tools/perf/util/stat-shadow.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 70c87fdb2a43..2c41d47f6f83 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -738,6 +738,8 @@ static void generic_metric(struct perf_stat_config *config,
 	char *n, *pn;
 
 	expr__ctx_init(&pctx);
+	/* Must be first id entry */
+	expr__add_id(&pctx, name, avg);
 	for (i = 0; metric_events[i]; i++) {
 		struct saved_value *v;
 		struct stats *stats;
@@ -776,8 +778,6 @@ static void generic_metric(struct perf_stat_config *config,
 			expr__add_id(&pctx, n, avg_stats(stats)*scale);
 	}
 
-	expr__add_id(&pctx, name, avg);
-
 	if (!metric_events[i]) {
 		const char *p = metric_expr;
 
-- 
2.21.0