[PATCH] perf tools: Fix segfault in cpu_cache_level__read

From: Jiri Olsa
Date: Thu Sep 12 2019 - 06:52:40 EST


We release wrong pointer on error path in
cpu_cache_level__read function, leading to
segfault:

(gdb) r record ls
Starting program: /root/perf/tools/perf/perf record ls
...
[ perf record: Woken up 1 times to write data ]
double free or corruption (out)

Thread 1 "perf" received signal SIGABRT, Aborted.
0x00007ffff7463798 in raise () from /lib64/power9/libc.so.6
(gdb) bt
#0 0x00007ffff7463798 in raise () from /lib64/power9/libc.so.6
#1 0x00007ffff7443bac in abort () from /lib64/power9/libc.so.6
#2 0x00007ffff74af8bc in __libc_message () from /lib64/power9/libc.so.6
#3 0x00007ffff74b92b8 in malloc_printerr () from /lib64/power9/libc.so.6
#4 0x00007ffff74bb874 in _int_free () from /lib64/power9/libc.so.6
#5 0x0000000010271260 in __zfree (ptr=0x7fffffffa0b0) at ../../lib/zalloc..
#6 0x0000000010139340 in cpu_cache_level__read (cache=0x7fffffffa090, cac..
#7 0x0000000010143c90 in build_caches (cntp=0x7fffffffa118, size=<optimiz..
...

Releasing the proper pointer.

Link: http://lkml.kernel.org/n/tip-e7js6xoi4y18kydxqehh0ihx@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/perf/util/header.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index b0c34dda30a0..3527b9897b6f 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1081,7 +1081,7 @@ static int cpu_cache_level__read(struct cpu_cache_level *cache, u32 cpu, u16 lev

scnprintf(file, PATH_MAX, "%s/shared_cpu_list", path);
if (sysfs__read_str(file, &cache->map, &len)) {
- zfree(&cache->map);
+ zfree(&cache->size);
zfree(&cache->type);
return -1;
}
--
2.21.0