[LTP] Revert "tpci: unbind driver in test_assign_resources()"

[Yizhou Tang]

On Wed, Jul 15, 2026 at 11:54 PM Andrea Cervesato
<andrea.cervesato@suse.com> wrote:
>
> Hi Yizhou,
>
> > Hi,
> >
> > We recently confirmed this commit does cause a flood of I/O errors on
> > the root filesystem in our testing, leaving the machine unusable until
> > reboot.
> >
> > Given that, we'd appreciate the community helping to decide soon
> > whether the revert is warranted.
>
> Are you 100% sure that is caused by the patch you want to revert?
> Because the patch looked ok to me when I reviewed. We need to have
> more context and info around the issue which has been generated in
> order to avoid any workaround for a system/kernel bug.
>

Hi Andrea,

I can't claim 100% certainty, as I'm not a PCI expert.

Let me give you the context we have. Environment: Ubuntu 24.04, kernel
built from the latest 6.6 stable branch. Root filesystem / is XFS on
/dev/sda4.
Reproducer: kirk -f kernel_misc -p tpci -v.

With dmesg -T --follow we captured:
[Fri Jul 10 19:22:08 2026] ltp_tpci: assign resource #6
[Fri Jul 10 19:22:08 2026] ltp_tpci: name = 0000:d7:12.2, flags = 0,
start 0x0, end 0x0
[Fri Jul 10 19:22:08 2026] ltp_tpci: test-case 13
[Fri Jul 10 19:22:08 2026] ltp_tpci: save state
[Fri Jul 10 19:22:08 2026] ltp_tpci: saved state of device
[Fri Jul 10 19:22:08 2026] ltp_tpci: test-case 14
[Fri Jul 10 19:22:08 2026] ltp_tpci: restore state
[Fri Jul 10 19:22:08 2026] ltp_tpci: test-case 15
[Fri Jul 10 19:22:08 2026] ltp_tpci: find device capability
[Fri Jul 10 19:22:08 2026] ltp_tpci: device has PM capability
[Fri Jul 10 19:22:08 2026] ltp_tpci: test-case 16
[Fri Jul 10 19:22:08 2026] ltp_tpci: device doesn't have PCI-EXP capability

At this point there is a gap of roughly one minute that no log could
not be captured. During that window the console scrolled a large
volume of messages too fast to record. Among what was visible on the
console was:
XFS (sda4): Please unmount the filesystem and rectify the problem(s).
What did make it into the log afterwards is only the resulting I/O-error flood:

[Fri Jul 10 19:23:06 2026] systemd-journald[818]: Failed to open
/var/log/journal/...: Input/output error (Dropped 2749 similar
message(s))
[Fri Jul 10 19:23:06 2026] systemd-journald[818]: Failed to rotate
/var/log/journal/.../system.journal: Input/output error (Dropped 4815
similar message(s))
[Fri Jul 10 19:23:06 2026] systemd-journald[818]: Failed to rotate
/var/log/journal/.../user-1000.journal: Input/output error
[Fri Jul 10 19:23:06 2026] systemd-journald[818]: Failed to open
/var/log/journal/...: Input/output error (Dropped 2406 similar
message(s))
[Fri Jul 10 19:23:06 2026] systemd-journald[818]: Failed to open
/var/log/journal/...: Input/output error

The machine is unusable after this and only recovers on reboot.

The one thing I can state with confidence: after reverting this patch,
the problem no longer reproduces on the same setup.

Best regards,
Yi

>
> Regards,
> --
> Andrea Cervesato
> SUSE QE Automation Engineer Linux
> andrea.cervesato@suse.com