futex_cmp_requeue01 from ubuntu_ltp_syscalls failed on B-KVM

[Po-Hsu Lin]

Issue found on B-KVM 4.15.0-1059.60

 startup='Thu Apr 16 19:43:55 2020'
 tst_test.c:1246: INFO: Timeout per run is 0h 05m 00s
 futex_cmp_requeue01.c:93: INFO: Test 0: waiters: 10, wakes: 3, requeues: 7
 futex_cmp_requeue01.c:115: INFO: futex_cmp_requeue() returned 10
 futex_cmp_requeue01.c:131: INFO: children woken, futex0: 0, futex1: 7, spurious wakeups: 0
 futex_cmp_requeue01.c:176: PASS: futex_cmp_requeue()
 futex_cmp_requeue01.c:93: INFO: Test 1: waiters: 10, wakes: 0, requeues: 10
 futex_cmp_requeue01.c:115: INFO: futex_cmp_requeue() returned 10
 futex_cmp_requeue01.c:131: INFO: children woken, futex0: 0, futex1: 10, spurious wakeups: 0
 futex_cmp_requeue01.c:176: PASS: futex_cmp_requeue()
 futex_cmp_requeue01.c:93: INFO: Test 2: waiters: 10, wakes: 2, requeues: 6
 futex_cmp_requeue01.c:115: INFO: futex_cmp_requeue() returned 8
 futex_cmp_requeue01.c:131: INFO: children woken, futex0: 2, futex1: 6, spurious wakeups: 0
 futex_cmp_requeue01.c:176: PASS: futex_cmp_requeue()
 futex_cmp_requeue01.c:93: INFO: Test 3: waiters: 100, wakes: 50, requeues: 50
 futex_cmp_requeue01.c:115: INFO: futex_cmp_requeue() returned 100
 futex_cmp_requeue01.c:131: INFO: children woken, futex0: 0, futex1: 50, spurious wakeups: 0
 futex_cmp_requeue01.c:176: PASS: futex_cmp_requeue()
 futex_cmp_requeue01.c:93: INFO: Test 4: waiters: 100, wakes: 0, requeues: 70
 futex_cmp_requeue01.c:115: INFO: futex_cmp_requeue() returned 70
 futex_cmp_requeue01.c:131: INFO: children woken, futex0: 30, futex1: 70, spurious wakeups: 0
 futex_cmp_requeue01.c:176: PASS: futex_cmp_requeue()
 futex_cmp_requeue01.c:84: BROK: fork() failed: EAGAIN/EWOULDBLOCK (11)

 Summary:
 passed 5
 failed 0
 skipped 0
 warnings 0
 tag=futex_cmp_requeue01 stime=1587066235 dur=0 exit=exited stat=2 core=no cu=5 cs=7

[Po-Hsu Lin (cypressyew)]

This is only affecting B-kvm, passed on Bionic kernel.

[Po-Hsu Lin (cypressyew)]

Spotted on 4.15.0-1071.72-kvm

[Po-Hsu Lin (cypressyew)]

Manually retested on instance moe with 4.15.0-1071-kvm, test passed.
(with just
futex_cmp_requeue01 futex_cmp_requeue01
futex_cmp_requeue02 futex_cmp_requeue02
futex_wait01 futex_wait01
futex_wait02 futex_wait02
futex_wait03 futex_wait03
futex_wait04 futex_wait04
futex_wait05 futex_wait05
futex_wake01 futex_wake01
futex_wake02 futex_wake02
futex_wake03 futex_wake03
futex_wake04 futex_wake04
)

Might be a glitch with all the tests running together?

[Po-Hsu Lin (cypressyew)]

Didn't see this on 4.15.0-1072.73-kvm with node harpo.
We can check if it's still passing in the next cycle and close this bug.

[Po-Hsu Lin (cypressyew)]

This issue does not exist with 4.15.0-1075.76-kvm