This test item has extremely high requirements for timing and can only
pass the test under specific conditions. The following situations will
lead to test failure:
MainThread Thread1
|
pthread_create-------------------
| |
futex_cmp_requeue |
| futex_wait
| |
If the child thread is not waiting in the futex_wait function when the
main thread reaches the futex_cmp_requeue function, the test will fail.
This patch avoids this problem by checking whether the child thread is
in a sleeping state in the main thread.
Fixes: 7cb5dd8e2c8c ("selftests: futex: Add futex compare requeue test")
Signed-off-by: Yuwen Chen <[email protected]>
Co-developed-by: Edward Liaw <[email protected]>
Signed-off-by: Edward Liaw <[email protected]>
---
.../futex/functional/futex_requeue.c | 65 ++++++++++++++++---
1 file changed, 55 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/futex/functional/futex_requeue.c
b/tools/testing/selftests/futex/functional/futex_requeue.c
index 35d4be23db5da..f17debd756303 100644
--- a/tools/testing/selftests/futex/functional/futex_requeue.c
+++ b/tools/testing/selftests/futex/functional/futex_requeue.c
@@ -7,21 +7,27 @@
#include <pthread.h>
#include <limits.h>
+#include <stdatomic.h>
#include "futextest.h"
#include "kselftest_harness.h"
-#define timeout_ns 30000000
+#define timeout_s 3 /* 3s */
#define WAKE_WAIT_US 10000
volatile futex_t *f1;
+static pthread_barrier_t barrier;
void *waiterfn(void *arg)
{
struct timespec to;
+ atomic_int *tid = (atomic_int *)arg;
- to.tv_sec = 0;
- to.tv_nsec = timeout_ns;
+ to.tv_sec = timeout_s;
+ to.tv_nsec = 0;
+
+ atomic_store(tid, gettid());
+ pthread_barrier_wait(&barrier);
if (futex_wait(f1, *f1, &to, 0))
printf("waiter failed errno %d\n", errno);
@@ -29,22 +35,50 @@ void *waiterfn(void *arg)
return NULL;
}
+static int get_thread_state(pid_t pid)
+{
+ FILE *fp;
+ char buf[80], tag[80];
+ char val = 0;
+
+ snprintf(buf, sizeof(buf), "/proc/%d/status", pid);
+ fp = fopen(buf, "r");
+ if (!fp)
+ return -1;
+
+ while (fgets(buf, sizeof(buf), fp))
+ if (fscanf(fp, "%s %c\n", tag, &val) == 2 && !strcmp(tag,
"State:"))
+ break;
+
+ fclose(fp);
+ return val;
+}
+
TEST(requeue_single)
{
volatile futex_t _f1 = 0;
volatile futex_t f2 = 0;
pthread_t waiter[10];
- int res;
+ atomic_int tid = 0;
+ int res, state;
f1 = &_f1;
+ pthread_barrier_init(&barrier, NULL, 2);
/*
* Requeue a waiter from f1 to f2, and wake f2.
*/
- if (pthread_create(&waiter[0], NULL, waiterfn, NULL))
+ if (pthread_create(&waiter[0], NULL, waiterfn, &tid))
ksft_exit_fail_msg("pthread_create failed\n");
- usleep(WAKE_WAIT_US);
+ pthread_barrier_wait(&barrier);
+ pthread_barrier_destroy(&barrier);
+ while ((state = get_thread_state(atomic_load(&tid))) != 'S') {
+ usleep(WAKE_WAIT_US);
+
+ if (state < 0)
+ break;
+ }
ksft_print_dbg_msg("Requeuing 1 futex from f1 to f2\n");
res = futex_cmp_requeue(f1, 0, &f2, 0, 1, 0);
@@ -69,7 +103,8 @@ TEST(requeue_multiple)
volatile futex_t _f1 = 0;
volatile futex_t f2 = 0;
pthread_t waiter[10];
- int res, i;
+ atomic_int tids[10] = {0};
+ int res, i, state;
f1 = &_f1;
@@ -78,11 +113,21 @@ TEST(requeue_multiple)
* At futex_wake, wake INT_MAX (should be exactly 7).
*/
for (i = 0; i < 10; i++) {
- if (pthread_create(&waiter[i], NULL, waiterfn, NULL))
+ pthread_barrier_init(&barrier, NULL, 2);
+
+ if (pthread_create(&waiter[i], NULL, waiterfn, &tids[i]))
ksft_exit_fail_msg("pthread_create failed\n");
- }
- usleep(WAKE_WAIT_US);
+ pthread_barrier_wait(&barrier);
+ pthread_barrier_destroy(&barrier);
+
+ while ((state = get_thread_state(atomic_load(&tids[i]))) !=
'S') {
+ usleep(WAKE_WAIT_US);
+
+ if (state < 0)
+ break;
+ }
+ }
ksft_print_dbg_msg("Waking 3 futexes at f1 and requeuing 7 futexes from
f1 to f2\n");
res = futex_cmp_requeue(f1, 0, &f2, 3, 7, 0);
--
2.34.1
