Dear Linux folks,
Running the selftests in a QEMU q35 VM, they hang.
```
$ make kselftest
[…]
ok 6 selftests: pidfd: pidfd_getfd_test
# timeout set to 45
# selftests: pidfd: pidfd_setns_test
# TAP version 13
# 1..7
# # Starting 7 tests from 2 test cases.
# # RUN global.setns_einval ...
# # OK global.setns_einval
# ok 1 global.setns_einval
# # RUN current_nsset.invalid_flags ...
# # pidfd_setns_test.c:161:invalid_flags:Expected self->child_pid_exited
(0) > 0 (0)
# # OK current_nsset.invalid_flags
# ok 2 current_nsset.invalid_flags
# # RUN current_nsset.pidfd_exited_child ...
# # pidfd_setns_test.c:161:pidfd_exited_child:Expected
self->child_pid_exited (0) > 0 (0)
# # OK current_nsset.pidfd_exited_child
# ok 3 current_nsset.pidfd_exited_child
# # RUN current_nsset.pidfd_incremental_setns ...
# # pidfd_setns_test.c:161:pidfd_incremental_setns:Expected
self->child_pid_exited (0) > 0 (0)
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to user namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to mnt namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to pid namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to uts namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to ipc namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to net namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to cgroup namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:408:pidfd_incremental_setns:Managed to correctly
setns to pid_for_children namespace of 31570 via pidfd 20
# # pidfd_setns_test.c:391:pidfd_incremental_setns:Expected
setns(self->child_pidfd1, info->flag) (-1) == 0 (0)
# # pidfd_setns_test.c:392:pidfd_incremental_setns:Too many users -
Failed to setns to time namespace of 31570 via pidfd 20
# # pidfd_incremental_setns: Test terminated by timeout
# # FAIL current_nsset.pidfd_incremental_setns
# not ok 4 current_nsset.pidfd_incremental_setns
# # RUN current_nsset.nsfd_incremental_setns ...
# # pidfd_setns_test.c:161:nsfd_incremental_setns:Expected
self->child_pid_exited (0) > 0 (0)
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to user namespace of 31577 via nsfd 19
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to mnt namespace of 31577 via nsfd 24
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to pid namespace of 31577 via nsfd 27
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to uts namespace of 31577 via nsfd 30
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to ipc namespace of 31577 via nsfd 33
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to net namespace of 31577 via nsfd 36
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to cgroup namespace of 31577 via nsfd 39
# # pidfd_setns_test.c:444:nsfd_incremental_setns:Managed to correctly
setns to pid_for_children namespace of 31577 via nsfd 42
# # pidfd_setns_test.c:427:nsfd_incremental_setns:Expected
setns(self->child_nsfds1[i], info->flag) (-1) == 0 (0)
# # pidfd_setns_test.c:428:nsfd_incremental_setns:Too many users -
Failed to setns to time namespace of 31577 via nsfd 45
```
Ctrl + c gets me back to the shell prompt.
```
$ ps auxf
[…]
build 31574 0.0 0.0 2528 1024 pts/0 D 09:57 0:00
./pidfd_setns_test
build 31575 99.9 0.0 2528 1024 pts/0 R 09:57 37:37 \_
./pidfd_setns_test
build 31576 0.0 0.0 0 0 pts/0 Z 09:57 0:00
\_ [pidfd_setns_tes] <defunct>
build 31577 0.0 0.0 0 0 pts/0 Z 09:57 0:00
\_ [pidfd_setns_tes] <defunct>
build 31578 0.0 0.0 2528 512 pts/0 S 09:57 0:00
\_ ./pidfd_setns_test
```
During shutdown, the system waits for that process:
[42733.704347] systemd-shutdown[1]: Waiting for process: 31578
(pidfd_setns_tes)
This is commit 8d025e2092e2 with one patch on top:
$ git log --no-decorate --oneline -2 a2ce022afcbb
a2ce022afcbb [PATCH] kbuild: Disable KCSAN for autogenerated
*.mod.c intermediaries
8d025e2092e2 Merge tag 'erofs-for-6.9-rc2-fixes' of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
KCSAN is not enabled though.
Kind regards,
Paul
