selftests: gpio-mockup-chardev: Check asprintf() for error

With gcc 7.3.0:

    gpio-mockup-chardev.c: In function ‘get_debugfs’:
    gpio-mockup-chardev.c:62:3: warning: ignoring return value of ‘asprintf’, declared with attribute warn_unused_result [-Wunused-result]
       asprintf(path, "%s/gpio", mnt_fs_get_target(fs));
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Handle asprintf() failures to fix this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Shuah Khan <shuah@kernel.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/testing/selftests/gpio/gpio-mockup-chardev.c b/tools/testing/selftests/gpio/gpio-mockup-chardev.c
index f8d468f54e98..aaa1e9f083c3 100644
--- a/tools/testing/selftests/gpio/gpio-mockup-chardev.c
+++ b/tools/testing/selftests/gpio/gpio-mockup-chardev.c
@@ -37,7 +37,7 @@ static int get_debugfs(char **path)
         struct libmnt_table *tb;
         struct libmnt_iter *itr = NULL;
         struct libmnt_fs *fs;
-        int found = 0;
+        int found = 0, ret;
 
         cxt = mnt_new_context();
         if (!cxt)
@@ -58,8 +58,11 @@ static int get_debugfs(char **path)
                         break;
                 }
         }
-        if (found)
-                asprintf(path, "%s/gpio", mnt_fs_get_target(fs));
+        if (found) {
+                ret = asprintf(path, "%s/gpio", mnt_fs_get_target(fs));
+                if (ret < 0)
+                        err(EXIT_FAILURE, "failed to format string");
+        }
 
         mnt_free_iter(itr);
         mnt_free_context(cxt);