Re: [PATCH v12 20/21] selftests/futex: Add futex_priv_hash

[André Almeida]

Hi Sebastian,

Thank you for adding a selftest for the new uAPI. The recent futex 
selftests accepted uses the kselftest helpers in a different way than 
the way you have used. I've attached a diff to exemplify how I would 
write this selftest. The advantage is to have a TAP output that can be 
easier used with automated testing, and that would not stop when the 
first test fails.

Em 16/04/2025 13:29, Sebastian Andrzej Siewior escreveu:
> Test the basic functionality of the private hash:
> - Upon start, with no threads there is no private hash.
> - The first thread initializes the private hash.
> - More than four threads will increase the size of the private hash if
>    the system has more than 16 CPUs online.
> - Once the user sets the size of private hash, auto scaling is disabled.
> - The user is only allowed to use numbers to the power of two.
> - The user may request the global or make the hash immutable.
> - Once the global hash has been set or the hash has been made immutable,
>    further changes are not allowed.
> - Futex operations should work the whole time. It must be possible to
>    hold a lock, such a PI initialised mutex, during the resize operation.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---

-- >8 --

---
 .../futex/functional/futex_priv_hash.c        | 31 ++++++++++++-------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/futex/functional/futex_priv_hash.c 
b/tools/testing/selftests/futex/functional/futex_priv_hash.c
index 4d37650baa19..33fa9ad11d69 100644
--- a/tools/testing/selftests/futex/functional/futex_priv_hash.c
+++ b/tools/testing/selftests/futex/functional/futex_priv_hash.c
@@ -51,15 +51,17 @@ static void futex_hash_slots_set_verify(int slots)

 	ret = futex_hash_slots_set(slots, 0);
 	if (ret != 0) {
-		error("Failed to set slots to %d\n", errno, slots);
-		exit(1);
+		ksft_test_result_fail("Failed to set slots to %d: %s\n", slots, 
strerror(errno));
+		return;
 	}
 	ret = futex_hash_slots_get();
 	if (ret != slots) {
-		error("Set %d slots but PR_FUTEX_HASH_GET_SLOTS returns: %d\n",
-		       errno, slots, ret);
-		exit(1);
+		ksft_test_result_fail("Set %d slots but PR_FUTEX_HASH_GET_SLOTS 
returns: %d\n",
+		       		      slots, ret);
+		return;
 	}
+
+	ksft_test_result_pass("futex_hash_slots_set() and get() succeeded (%d 
slots)\n", slots);
 }

 static void futex_hash_slots_set_must_fail(int slots, int immutable)
@@ -67,12 +69,14 @@ static void futex_hash_slots_set_must_fail(int 
slots, int immutable)
 	int ret;

 	ret = futex_hash_slots_set(slots, immutable);
-	if (ret < 0)
+	if (ret < 0) {
+		ksft_test_result_pass("invalid futex_hash_slots_set(%d, %d) 
succeeded.\n",
+				slots, immutable);
 		return;
+	}

-	fail("futex_hash_slots_set(%d, %d) expected to fail but succeeded.\n",
+	ksft_test_result_fail("futex_hash_slots_set(%d, %d) expected to fail 
but succeeded.\n",
 	       slots, immutable);
-	exit(1);
 }

 static void *thread_return_fn(void *arg)
@@ -156,6 +160,8 @@ int main(int argc, char *argv[])
 		}
 	}

+	ksft_print_header();
+	ksft_set_plan(13);

 	ret = pthread_mutexattr_init(&mutex_attr_pi);
 	ret |= pthread_mutexattr_setprotocol(&mutex_attr_pi, 
PTHREAD_PRIO_INHERIT);
@@ -235,13 +241,13 @@ int main(int argc, char *argv[])

 	ret = futex_hash_slots_set(15, 0);
 	if (ret >= 0) {
-		fail("Expected to fail with 15 slots but succeeded: %d.\n", ret);
+		ksft_test_result_fail("Expected to fail with 15 slots but succeeded: 
%d.\n", ret);
 		return 1;
 	}
 	futex_hash_slots_set_verify(2);
 	join_max_threads();
 	if (counter != MAX_THREADS) {
-		fail("Expected thread counter at %d but is %d\n",
+		ksft_test_result_fail("Expected thread counter at %d but is %d\n",
 		       MAX_THREADS, counter);
 		return 1;
 	}
@@ -254,8 +260,7 @@ int main(int argc, char *argv[])

 	ret = futex_hash_slots_get();
 	if (ret != 2) {
-		printf("Expected 2 slots, no auto-resize, got %d\n", ret);
-		return 1;
+		ksft_test_result_fail("Expected 2 slots, no auto-resize, got %d\n", ret);
 	}

 	futex_hash_slots_set_must_fail(1 << 29, 0);
@@ -311,5 +316,7 @@ int main(int argc, char *argv[])
 		fail("Expected immutable private hash, got %d\n", ret);
 		return 1;
 	}
+
+	ksft_print_cnts();
 	return 0;
 }
--
2.49.0