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>

diff --git a/tools/testing/selftests/gpio/gpio-mockup-chardev.c b/tools/testing/selftests/gpio/gpio-mockup-chardev.c
index f8d468f..aaa1e9f 100644 (file)
--- 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);