Timing unit tests: more protection against infinite loops
If timing_timer_simple fails because it detects that timers are likely
to never expire (e.g. going backward or not incrementing), skip all
tests that rely on timers.
diff --git a/tests/suites/test_suite_timing.function b/tests/suites/test_suite_timing.function
index 71fe7ed..1610155 100644
--- a/tests/suites/test_suite_timing.function
+++ b/tests/suites/test_suite_timing.function
@@ -38,6 +38,14 @@
0 );
}
+/* Some conditions in timing_timer_simple suggest that timers are unreliable.
+ Most other test cases rely on timers to terminate, and could loop
+ indefinitely if timers are too broken. So if timing_timer_simple detected a
+ timer that risks not terminating (going backwards, or not reaching the
+ desired count in the alloted clock cycles), set this flag to immediately
+ fail those other tests without running any timers. */
+static int timers_are_badly_broken = 0;
+
/* END_HEADER */
/* BEGIN_DEPENDENCIES
@@ -73,6 +81,15 @@
return;
exit:
+ if( iterations >= TIMING_SHORT_TEST_ITERATIONS_MAX ||
+ new_millis < millis )
+ {
+ /* The timer was very unreliable: it didn't increment and the loop ran
+ out, or it went backwards. Other tests that use timers might go
+ into an infinite loop, so we'll skip them. */
+ timers_are_badly_broken = 1;
+ }
+
/* No cleanup needed, but show some diagnostic iterations, because timing
problems can be hard to reproduce. */
mbedtls_fprintf( stdout, " Finished with millis=%lu new_millis=%lu get(timer)<=%lu iterations=%lu\n",
@@ -87,6 +104,11 @@
struct mbedtls_timing_hr_time timer;
unsigned long millis = 0;
unsigned long iterations = 0;
+
+ /* Skip this test if it looks like timers don't work at all, to avoid an
+ infinite loop below. */
+ TEST_ASSERT( !timers_are_badly_broken );
+
/* Start the timer. Timers are always reset to 0. */
TEST_ASSERT( mbedtls_timing_get_timer( &timer, 1 ) == 0 );
/* Busy-wait loop for a few milliseconds */
@@ -107,9 +129,10 @@
exit:
/* No cleanup needed, but show some diagnostic information, because timing
problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with millis=%lu get(timer)<=%lu iterations=%lu\n",
- millis, mbedtls_timing_get_timer( &timer, 0 ),
- iterations );
+ if( !timers_are_badly_broken )
+ mbedtls_fprintf( stdout, " Finished with millis=%lu get(timer)<=%lu iterations=%lu\n",
+ millis, mbedtls_timing_get_timer( &timer, 0 ),
+ iterations );
}
/* END_CASE */
@@ -117,7 +140,11 @@
void timing_two_timers( int delta )
{
struct mbedtls_timing_hr_time timer1, timer2;
- unsigned long millis1, millis2;
+ unsigned long millis1 = 0, millis2 = 0;
+
+ /* Skip this test if it looks like timers don't work at all, to avoid an
+ infinite loop below. */
+ TEST_ASSERT( !timers_are_badly_broken );
/* Start the first timer and wait for a short time. */
(void) mbedtls_timing_get_timer( &timer1, 1 );
@@ -153,9 +180,10 @@
exit:
/* No cleanup needed, but show some diagnostic iterations, because timing
problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with millis1=%lu get(timer1)<=%lu millis2=%lu get(timer2)<=%lu\n",
- millis1, mbedtls_timing_get_timer( &timer1, 0 ),
- millis2, mbedtls_timing_get_timer( &timer2, 0 ) );
+ if( !timers_are_badly_broken )
+ mbedtls_fprintf( stdout, " Finished with millis1=%lu get(timer1)<=%lu millis2=%lu get(timer2)<=%lu\n",
+ millis1, mbedtls_timing_get_timer( &timer1, 0 ),
+ millis2, mbedtls_timing_get_timer( &timer2, 0 ) );
}
/* END_CASE */
@@ -177,6 +205,10 @@
TIMING_ALARM_0_DELAY_MS );
unsigned long iterations = 0;
+ /* Skip this test if it looks like timers don't work at all, to avoid an
+ infinite loop below. */
+ TEST_ASSERT( !timers_are_badly_broken );
+
/* Set an alarm and count how long it takes with a timer. */
(void) mbedtls_timing_get_timer( &timer, 1 );
mbedtls_set_alarm( seconds );
@@ -209,10 +241,11 @@
exit:
/* Show some diagnostic iterations, because timing
problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with alarmed=%d millis=%lu get(timer)<=%lu iterations=%lu\n",
- mbedtls_timing_alarmed,
- millis, mbedtls_timing_get_timer( &timer, 0 ),
- iterations );
+ if( !timers_are_badly_broken )
+ mbedtls_fprintf( stdout, " Finished with alarmed=%d millis=%lu get(timer)<=%lu iterations=%lu\n",
+ mbedtls_timing_alarmed,
+ millis, mbedtls_timing_get_timer( &timer, 0 ),
+ iterations );
/* Cleanup */
mbedtls_timing_alarmed = 0;
}
@@ -228,7 +261,7 @@
mbedtls_timing_delay_context delay;
struct mbedtls_timing_hr_time timer;
- unsigned long delta; /* delay started between timer=0 and timer=delta */
+ unsigned long delta = 0; /* delay started between timer=0 and timer=delta */
unsigned long before = 0, after = 0;
unsigned long iterations = 0;
int status = -2;
@@ -238,6 +271,10 @@
assert( int_ms >= 0 );
assert( fin_ms >= 0 );
+ /* Skip this test if it looks like timers don't work at all, to avoid an
+ infinite loop below. */
+ TEST_ASSERT( !timers_are_badly_broken );
+
/* Start a reference timer. Program a delay, and verify that the status of
the delay is consistent with the time given by the reference timer. */
(void) mbedtls_timing_get_timer( &timer, 1 );
@@ -310,8 +347,9 @@
exit:
/* No cleanup needed, but show some diagnostic iterations, because timing
problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with delta=%lu before=%lu after=%lu status=%d iterations=%lu\n",
- delta, before, after, status, iterations );
+ if( !timers_are_badly_broken )
+ mbedtls_fprintf( stdout, " Finished with delta=%lu before=%lu after=%lu status=%d iterations=%lu\n",
+ delta, before, after, status, iterations );
if( warn_inconclusive )
mbedtls_fprintf( stdout, " Inconclusive test, try running it on a less heavily loaded machine.\n" );
}
@@ -326,7 +364,11 @@
completely nonsensical values. */
struct mbedtls_timing_hr_time timer;
- unsigned long hardclock0, hardclock1, delta1;
+ unsigned long hardclock0 = -1, hardclock1 = -1, delta1 = -1;
+
+ /* Skip this test if it looks like timers don't work at all, to avoid an
+ infinite loop below. */
+ TEST_ASSERT( !timers_are_badly_broken );
hardclock0 = mbedtls_timing_hardclock( );
/* Wait 2ms to ensure a nonzero delay. Since the timer interface has 1ms
@@ -354,7 +396,8 @@
exit:
/* No cleanup needed, but show some diagnostic iterations, because timing
problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with hardclock=%lu,%lu\n",
- hardclock0, hardclock1 );
+ if( !timers_are_badly_broken )
+ mbedtls_fprintf( stdout, " Finished with hardclock=%lu,%lu\n",
+ hardclock0, hardclock1 );
}
/* END_CASE */