selftests: timers: set-timer-lat: Fix hang when testing unsupported alarms

When timer_create() fails on a bootime or realtime clock, setup_timer()
returns 0 as if timer has been set. Callers wait forever for the timer
to expire.

This hang is seen on a system that doesn't have support for:

CLOCK_REALTIME_ALARM   ABSTIME missing CAP_WAKE_ALARM? : [UNSUPPORTED]

Test hangs waiting for a timer that hasn't been set to expire. Fix
setup_timer() to return 1, add handling in callers to detect the
unsupported case and return 0 without waiting to not fail the test.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c
index ea1af5dbc7b6..50da45437daa 100644
--- a/tools/testing/selftests/timers/set-timer-lat.c
+++ b/tools/testing/selftests/timers/set-timer-lat.c
@@ -143,7 +143,8 @@ int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
                         printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
                                         clockstring(clock_id),
                                         flags ? "ABSTIME":"RELTIME");
-                        return 0;
+                        /* Indicate timer isn't set, so caller doesn't wait */
+                        return 1;
                 }
                 printf("%s - timer_create() failed\n", clockstring(clock_id));
                 return -1;
@@ -213,8 +214,9 @@ int do_timer(int clock_id, int flags)
         int err;
 
         err = setup_timer(clock_id, flags, interval, &tm1);
+        /* Unsupported case - return 0 to not fail the test */
         if (err)
-                return err;
+                return err == 1 ? 0 : err;
 
         while (alarmcount < 5)
                 sleep(1);
@@ -231,8 +233,9 @@ int do_timer_oneshot(int clock_id, int flags)
         int err;
 
         err = setup_timer(clock_id, flags, interval, &tm1);
+        /* Unsupported case - return 0 to not fail the test */
         if (err)
-                return err;
+                return err == 1 ? 0 : err;
 
         memset(&timeout, 0, sizeof(timeout));
         timeout.tv_sec = 5;