selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices

[Naresh Kamboju]

selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64,
i386 and arm64 Juno-r2
These devices are using NFS mounted rootfs.
I have tested pidfd testcases independently and all test PASS.

The Hang or exit from test run noticed when run by run_kselftest.sh

pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd,
&info, WSTOPPED, NULL) (-1) == 0 (0)
wait_nonblock: Test terminated by assertion

metadata:
  git branch: master
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
  git commit: e64997027d5f171148687e58b78c8b3c869a6158
  git describe: next-20200922
  make_kernelversion: 5.9.0-rc6
  kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config

Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>

Test output log:
---------------------
[ 1385.104983] audit: type=1701 audit(1600804535.960:87865):
auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=31268
comm=\"pidfd_wait\"
exe=\"/opt/kselftests/default-in-kernel/pidfd/pidfd_wait\" sig=6 res=1

# selftests: pidfd: pidfd_wait
# TAP version 13
# 1..3
# # Starting 3 tests from 1 test cases.
# #  RUN           global.wait_simple ...
# #            OK  global.wait_simple
# ok 1 global.wait_simple
# #  RUN           global.wait_states ...
# #            OK  global.wait_states
# ok 2 global.wait_states
# #  RUN           global.wait_nonblock ...
# # pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd,
&info, WSTOPPED, NULL) (-1) == 0 (0)
# # wait_nonblock: Test terminated by assertion
# #          FAIL  global.wait_nonblock
# not ok 3 global.wait_nonblock
# # FAILED: 2 / 3 tests passed.
# # Totals: pass:2 fail:1 xfail:0 xpass:0 skip:0 error:0
Marking unfinished test run as failed

ref:
https://lkft.validation.linaro.org/scheduler/job/1782129#L11737
https://lkft.validation.linaro.org/scheduler/job/1782130#L12735
https://lkft.validation.linaro.org/scheduler/job/1782138#L14178

-- 
Linaro LKFT
https://lkft.linaro.org