From: Ben Hutchings ben@decadent.org.uk

Depending on which functions are inlined in util/pmu.c, the snprintf() calls in perf_pmu__parse_{scale,unit,per_pkg,snapshot}() might trigger a warning:

util/pmu.c: In function 'pmu_aliases': util/pmu.c:178:31: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=] snprintf(path, PATH_MAX, "%s/%s.unit", dir, name); ^~

I found this when trying to build perf from Linux 3.16 with gcc 8. However I can reproduce the problem in mainline if I force __perf_pmu__new_alias() to be inlined.

Suppress this by using scnprintf() as has been done elsewhere in perf.

Signed-off-by: Ben Hutchings ben@decadent.org.uk Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20181111184524.fux4taownc6ndbx6@decadent.org.uk Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com --- tools/perf/util/pmu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 7e49baad304d..7348eea0248f 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -145,7 +145,7 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char * int fd, ret = -1; char path[PATH_MAX];

- snprintf(path, PATH_MAX, "%s/%s.scale", dir, name); + scnprintf(path, PATH_MAX, "%s/%s.scale", dir, name);

fd = open(path, O_RDONLY); if (fd == -1) @@ -175,7 +175,7 @@ static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, char *dir, char *n ssize_t sret; int fd;

- snprintf(path, PATH_MAX, "%s/%s.unit", dir, name); + scnprintf(path, PATH_MAX, "%s/%s.unit", dir, name);

fd = open(path, O_RDONLY); if (fd == -1) @@ -205,7 +205,7 @@ perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, char *dir, char *name) char path[PATH_MAX]; int fd;

- snprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name); + scnprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name);

fd = open(path, O_RDONLY); if (fd == -1) @@ -223,7 +223,7 @@ static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias, char path[PATH_MAX]; int fd;

- snprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name); + scnprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name);

fd = open(path, O_RDONLY); if (fd == -1)