[Bug 2133480] Re: Ubuntu25.10: Ubuntu host installation is failing while doing installation on multiple[2 or more] multipath SAN disks!

[Frank Heimes]

Hi Aditi, we just had a discussion about this case and one question came
up:

There are different ways to have two (actually multiple) LUNs in a single system.
a) one pair of host-bus adapters (HBAs), where each HBA has (and sees) both two LUNs
b) two (independent) pairs of host-bus adapters, where each HBA has (and sees) only one, single LUN
   (so one pair holds one LUN and the other pair holds the other LUN)

Can you please let us know how it's configured in your particular case?

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Title:
  Ubuntu25.10: Ubuntu host installation is failing while doing
  installation on multiple[2 or more] multipath SAN disks!

Status in The Ubuntu-power-systems project:
  New
Status in subiquity package in Ubuntu:
  New

Bug description:
  == Comment: #0 - Anushree Mathur <Anushree.Mathur2 at ibm.com> - 2025-11-28 03:12:11 ==
  ENV :
  HOST OS : Ubuntu 25.10 

  Host installation is crashing with following crash when we do
  installation on multiple[2 or more] SAN disks and we see -EBUSY error
  with specific mpath disk.

  generating crash report
  report saved to /var/crash/1760429899.735880613.ui.crash
  Traceback (most recent call last):
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/controllers/filesystem.py", line 296, in _guided_choice
      self.ui.set_body(FilesystemView(self.model, self))
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 485, in __init__
      self.refresh_model_inputs()
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 544, in refresh_model_inputs
      self.used_list.refresh_model_inputs()
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 417, in refresh_model_inputs
      for obj, cells in summarize_device(device, filter):
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/helpers.py", line 32, in summarize_device
      anns = labels.annotations(device) + labels.usage_labels(device)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/usr/lib/python3.12/functools.py", line 909, in wrapper
      return dispatch(args[0].__class__)(*args, **kw)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/common/filesystem/labels.py", line 101, in _annotations_vg
      member = next(iter(vg.devices))
               ^^^^^^^^^^^^^^^^^^^^^^
  StopIteration

  The above exception was the direct cause of the following exception:

  Traceback (most recent call last):
    File "/snap/subiquity/6868/usr/bin/subiquity", line 8, in <module>
      sys.exit(main())
               ^^^^^^
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/cmd/tui.py", line 161, in main
      asyncio.run(run_with_loop())
    File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line 194, in run
      return runner.run(main)
             ^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line 118, in run
      return self._loop.run_until_complete(task)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/base_events.py", line 687, in run_until_complete
      return future.result()
             ^^^^^^^^^^^^^^^
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/cmd/tui.py", line 159, in run_with_loop
      await subiquity_interface.run()
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/client.py", line 426, in run
      await super().run()
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquitycore/tui.py", line 390, in run
      await super().run()
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquitycore/core.py", line 133, in run
      raise exc
    File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/controllers/filesystem.py", line 300, in show_guided_and_redraw
      await self._guided_choice(choice)
  RuntimeError: coroutine raised StopIteration
                                                                                                            ^[[29;1R^[[29;106R
  Ubuntu Questing Quokka (development branch) ubuntu-server hvc

  
  Explaining whole scenario:

  When I tried to install my P11 lpar with Ubuntu with SAN disk
  1) 4 SAN disks are there
  2) I installed on mpatha (installation worked fine)
  3) I installed on mpathb (installation worked fine)
  4) When i rebooted the system connected to the console and then I tried to reinstall the system it gave the error message [-EBUSY] and then installation crashed

  My analysis:

  In the background, after each boot I was entering the shell and was checking for the multipath status:
  1) In the first attempt when i checked it gave all four disks
  2) After mpatha installation also all disks were listed in multipath -ll
  3) After mpathb installation also all disks were there
  4) When I tried the reinstallation after this I saw that multipath service itself gave the error as :

  [2168]: updated bindings file /etc/multipath/bindings
  [2168]: mpathb: addmap [0 230686720 multipath 1 queue_if_no_path 1 alua 2 1 ser>
  [2168]: libdevmapper: ioctl/libdm-iface.c(1995): device-mapper: reload ioctl on>
  [2168]: dm_addmap: libdm task=0 error: Device or resource busy
  [2168]: mpathb: ignoring map
  [2168]: mpathb: addmap [0 230686720 multipath 1 queue_if_no_path 1 alua 2 1 ser>
  [2168]: libdevmapper: ioctl/libdm-iface.c(1995): device-mapper: reload ioctl on>
  [2168]: dm_addmap: libdm task=0 error: Device or resource busy
  [2168]: mpathb: ignoring map
  : Started multipathd.service - Device-Mapper Multipath Device Controller.

  5) With multipath -ll I was not able to see mpathb there
  6) multipath service is not failing to restart but it is throwing this error message because mapping is not happening properly!
  I feel because of some stale metadata present on the mapathb at the time of installation which shouldn't have been there, it has happened.

  
  I tried this exact same scenario even on my P10 lpar which had 2 disks and I observed same kind of behavior! 

  Reproducibility with this exact scenario is 95%. 
  Reference bug is https://bugzilla.linux.ibm.com/show_bug.cgi?id=208604 but now the scenario has been changed!

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