[igt-dev] [PATCH i-g-t v2] intel_gpu_top: Fix cleanup on old kernels / unsupported GPU

Tvrtko Ursulin
2023-01-23T11:31:38Z

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Avoid trying to dereference null engines on exit when there are either
none which are supported, or kernel does not have i915 PMU support.

Also fix a memory leak on the same failure path just so Valgrind runs are
quite.

v2:
* Fix a memory leak in the same failure mode too.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Nirmoy Das <nirmoy.das@intel.com> # v1
---
tools/intel_gpu_top.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c
index 7aa233570463..0a1de41b3374 100644
--- a/tools/intel_gpu_top.c
+++ b/tools/intel_gpu_top.c
@@ -340,7 +340,7 @@ static struct engines *discover_engines(char *device)

d = opendir(sysfs_root);
if (!d)
- return NULL;
+ goto err;

while ((dent = readdir(d)) != NULL) {
const char *endswith = "-busy";
@@ -423,10 +423,8 @@ static struct engines *discover_engines(char *device)
}

if (ret) {
- free(engines);
errno = ret;
-
- return NULL;
+ goto err;
}

qsort(engine_ptr(engines, 0), engines->num_engines,
@@ -435,6 +433,11 @@ static struct engines *discover_engines(char *device)
engines->root = d;

return engines;
+
+err:
+ free(engines);
+
+ return NULL;
}

static void free_engines(struct engines *engines)
@@ -448,6 +451,9 @@ static void free_engines(struct engines *engines)
};
unsigned int i;

+ if (!engines)
+ return;
+
for (pmu = &free_list[0]; *pmu; pmu++) {
if ((*pmu)->present)
free((char *)(*pmu)->units);
@@ -2568,7 +2574,7 @@ int main(int argc, char **argv)
"Failed to detect engines! (%s)\n(Kernel 4.16 or newer is required for i915 PMU support.)\n",
strerror(errno));
ret = EXIT_FAILURE;
- goto err;
+ goto err_engines;
}

ret = pmu_init(engines);
@@ -2585,7 +2591,7 @@ int main(int argc, char **argv)
"More information can be found at 'Perf events and tool security' document:\n"
"https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html\n");
ret = EXIT_FAILURE;
- goto err;
+ goto err_pmu;
}

ret = EXIT_SUCCESS;
@@ -2699,8 +2705,9 @@ int main(int argc, char **argv)
free_clients(clients);

free(codename);
-err:
+err_pmu:
free_engines(engines);
+err_engines:
free(pmu_device);
exit:
igt_devices_free();
--
2.34.1