On Wed, 08 Jul 2026 01:31:45 +0200, Thomas Gleixner wrote:
> Do you have /proc/ disabled by chance or is it not accessible for the
> test case?
...
> Seems to correlate with the test case failure: Connection timed out :)
I used the following patch to simulate the situation where the proc file
system is not mounted on the system. The log is very similar to that of
the current problem.
--- a/tools/testing/selftests/futex/include/futex_thread.h
+++ b/tools/testing/selftests/futex/include/futex_thread.h
@@ -62,7 +62,8 @@ static inline int futex_wait_for_thread(struct futex_thread
*t, struct __test_me
int res;
snprintf(fname, sizeof(fname), "/proc/%d/wchan", t->tid);
- fp = fopen(fname, "r");
+ errno = ENOENT;
+ fp = NULL;
if (!fp) {
/* If /proc/... is not available, sleep */
if (errno != ENOENT)
The corresponding logs are as follows:
TAP version 13
1..2
# Starting 2 tests from 1 test cases.
# RUN global.requeue_single ...
# ../include/futex_thread.h:71:requeue_single:/proc/$PID/wchan not
accessible, continue with sleep()
# futex_requeue.c:28:requeue_single:Expected res (-1) == 0 (0)
# futex_requeue.c:52:requeue_single:Expected futex_cmp_requeue(f1, 0, &f2, 0,
1, 0) (0) == 1 (1)
# futex_requeue.c:53:requeue_single:Expected futex_wake(&f2, 1, 0) (0) == 1
(1)
# futex_requeue.c:29:requeue_single:waiter failed errno 110: Connection timed
out
# requeue_single: Test failed
# FAIL global.requeue_single
not ok 1 global.requeue_single
# RUN global.requeue_multiple ...
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# futex_requeue.c:28:requeue_multiple:Expected res (-1) == 0 (0)
# futex_requeue.c:29:requeue_multiple:waiter failed errno 110: Connection
timed out
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# ../include/futex_thread.h:71:requeue_multiple:/proc/$PID/wchan not
accessible, continue with sleep()
# futex_requeue.c:80:requeue_multiple:Expected futex_cmp_requeue(f1, 0, &f2,
3, 7, 0) (0) == 10 (10)
# futex_requeue.c:81:requeue_multiple:Expected futex_wake(&f2, INT_MAX, 0)
(0) == 7 (7)
# requeue_multiple: Test failed
# FAIL global.requeue_multiple
not ok 2 global.requeue_multiple
# FAILED: 0 / 2 tests passed.
# Totals: pass:0 fail:2 xfail:0 xpass:0 skip:0 error:0
I suggested adding a parameter for the waiting time to the
futex_wait_for_thread function.
In this way, when the proc file system is not mounted on the system, the old
solution
can still be used.
Thanks.
