[BUG BISECT] "Support fs_context" causes systemd issues (linux-next)

[Krzysztof KozÅowski]

Hi,

On recent linux-next, the commit f8076f3b0996 ("kernfs, sysfs, cgroup,
intel_rdt: Support fs_context") causes weird behavior of two of
systemd units: systemd-timesyncd.service and systemd-resolved.service
fail to start.

Logs:

Jul 18 09:51:33 odroidu3 systemd[376]: systemd-timesyncd.service:
Failed to set up mount namespacing: Invalid argument
Jul 18 09:51:33 odroidu3 systemd[376]: systemd-timesyncd.service:
Failed at step NAMESPACE spawning /usr/lib/systemd/systemd-timesyncd:
Invalid argument
Jul 18 09:51:33 odroidu3 systemd[1]: systemd-timesyncd.service: Main
process exited, code=exited, status=226/NAMESPACE
Jul 18 09:51:33 odroidu3 systemd[1]: systemd-timesyncd.service: Failed
with result 'exit-code'.

The configuration:

1. exynos_defconfig
2. ARMv7, octa-core (Cortex-A7+A15), Exynos5422 SoC, Odroid XU3 family
3. ARMv7, quad-core, Exynos4412 SoC, Odroid U3
4. The board boots from TFTP with NFS root (NFSv4)
5. Arch ARM Linux
6. Systemd: v236

Example of boot (logs):
https://krzk.eu/#/builders/21/builds/767/steps/10/logs/serial0


Bisect log:
git bisect start
# good: [30b06abfb92bfd5f9b63ea6a2ffb0bd905d1a6da] Merge tag
'pinctrl-v4.18-3' of
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
git bisect good 30b06abfb92bfd5f9b63ea6a2ffb0bd905d1a6da
# bad: [1dcbe5f2c615337cb7d4e13fab198ab716180733] Add linux-next
specific files for 20180717
git bisect bad 1dcbe5f2c615337cb7d4e13fab198ab716180733
# bad: [209dba6cb2664f6ac48282d666f2b4787286311a] Merge
remote-tracking branch 'crypto/master'
git bisect bad 209dba6cb2664f6ac48282d666f2b4787286311a
# good: [5bd2314d41ad09c497bb72ad3cf94f65913a7da1] Merge
remote-tracking branch 'overlayfs/overlayfs-next'
git bisect good 5bd2314d41ad09c497bb72ad3cf94f65913a7da1
# skip: [dc989d2ce2c2bc4b5cdc92a9d2c8a5c857448475] tools: bpftool:
don't pass FEATURES_DUMP to libbpf
git bisect skip dc989d2ce2c2bc4b5cdc92a9d2c8a5c857448475
# good: [a1bf74dc6e66f91325cc8d35231e151a24a1f9ff] net/mlx5e: Add
channel events counter
git bisect good a1bf74dc6e66f91325cc8d35231e151a24a1f9ff
# bad: [460b2b7ca7db36621315032f5fc4ca85e0b64589] Merge
remote-tracking branch 'rdma/for-next'
git bisect bad 460b2b7ca7db36621315032f5fc4ca85e0b64589
# bad: [a9d11c1d00c560d86855b24f84457a191e70ca4a] Merge
remote-tracking branch 'jc_docs/docs-next'
git bisect bad a9d11c1d00c560d86855b24f84457a191e70ca4a
# bad: [82ffa5de1706a23797d2409e09917bfd56222d32] Merge
remote-tracking branch 'printk/for-next'
git bisect bad 82ffa5de1706a23797d2409e09917bfd56222d32
# good: [e339dd8d8b045399e918c6737b2cc435b21a451e] xfs: use sync
buffer I/O for sync delwri queue submission
git bisect good e339dd8d8b045399e918c6737b2cc435b21a451e
# bad: [ee12a8e0dfcd34069fe1781f2e9d0d8c5fd4e1db] afs: Add fsinfo support
git bisect bad ee12a8e0dfcd34069fe1781f2e9d0d8c5fd4e1db
# good: [96e6c5ff548b9e18ef84b326b5c4c9e59a01e44b] proc: Add
fs_context support to procfs
git bisect good 96e6c5ff548b9e18ef84b326b5c4c9e59a01e44b
# bad: [1ead04847d5b772c53b6d46f0670c83c8a081456] vfs: Implement
fsopen() to prepare for a mount
git bisect bad 1ead04847d5b772c53b6d46f0670c83c8a081456
# bad: [a32434fa30a7f4390aa409726fa08ed4ac802078] hugetlbfs: Convert
to fs_context
git bisect bad a32434fa30a7f4390aa409726fa08ed4ac802078
# good: [6e705c4c287ed7f7bf4fe04c7884e29dd5a9a33d] cpuset: Use fs_context
git bisect good 6e705c4c287ed7f7bf4fe04c7884e29dd5a9a33d
# bad: [f8076f3b0996b70f62b32d9c52649ea9bab2d6cd] kernfs, sysfs,
cgroup, intel_rdt: Support fs_context
git bisect bad f8076f3b0996b70f62b32d9c52649ea9bab2d6cd
# first bad commit: [f8076f3b0996b70f62b32d9c52649ea9bab2d6cd] kernfs,
sysfs, cgroup, intel_rdt: Support fs_context

Any hints how to debug this issue?

Best regards,
Krzysztof