[PATCH 30/32] perf bench numa: Avoid possible truncation when using snprintf()

From: Arnaldo Carvalho de Melo
Date: Thu Feb 09 2017 - 21:59:51 EST


From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Addressing this warning from gcc 7:

CC /tmp/build/perf/bench/numa.o
bench/numa.c: In function '__bench_numa':
bench/numa.c:1582:42: error: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size between 8 and 17 [-Werror=format-truncation=]
snprintf(tname, 32, "process%d:thread%d", p, t);
^~
bench/numa.c:1582:25: note: directive argument in the range [0, 2147483647]
snprintf(tname, 32, "process%d:thread%d", p, t);
^~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:939:0,
from bench/../util/util.h:47,
from bench/../builtin.h:4,
from bench/numa.c:11:
/usr/include/bits/stdio2.h:64:10: note: '__builtin___snprintf_chk' output between 17 and 35 bytes into a destination of size 32
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __va_arg_pack ());
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Petr Holasek <pholasek@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-twa37vsfqcie5gwpqwnjuuz9@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/bench/numa.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 8efe904e486b..9e5a02d6b9a9 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -1573,13 +1573,13 @@ static int __bench_numa(const char *name)
"GB/sec,", "total-speed", "GB/sec total speed");

if (g->p.show_details >= 2) {
- char tname[32];
+ char tname[14 + 2 * 10 + 1];
struct thread_data *td;
for (p = 0; p < g->p.nr_proc; p++) {
for (t = 0; t < g->p.nr_threads; t++) {
- memset(tname, 0, 32);
+ memset(tname, 0, sizeof(tname));
td = g->threads + p*g->p.nr_threads + t;
- snprintf(tname, 32, "process%d:thread%d", p, t);
+ snprintf(tname, sizeof(tname), "process%d:thread%d", p, t);
print_res(tname, td->speed_gbs,
"GB/sec", "thread-speed", "GB/sec/thread speed");
print_res(tname, td->system_time_ns / NSEC_PER_SEC,
--
2.9.3