Re: [PATCH for-9.2 00/10] s390: Convert virtio-ccw, cpu to three-phase reset, and followup cleanup

[Nico Boehr]

Quoting Nico Boehr (2024-08-26 14:08:20)
> There was a little hickup without the fixup to patch 2, but after Nina
> pushed the fixup, we did not observe any failures related to your
> changes in our CI. Thanks!

Peter, after a few CI runs, we unfortunately did find some issues with your
patch :-(

Rebooting a guest in a loop sometimes fails. Michael was able to bisect it
to your series.

The problem is intermittent. The guest is unable to load its initramfs:

  [    0.560674] rootfs image is not initramfs (no cpio magic); looks like an 
initrd
  [    0.588605] Freeing initrd memory: 95680K
  [    0.593143] md: Waiting for all devices to be available before autodetect
  [    0.593144] md: If you don't use raid, use raid=noautodetect
  [    0.593145] md: Autodetecting RAID arrays.
  [    0.593146] md: autorun ...
  [    0.593147] md: ... autorun DONE.
  [    0.593156] RAMDISK: gzip image found at block 0
  [    0.609110] RAMDISK: incomplete write (29120 != 32768)
  [    0.609113] write error

...and then a panic because the kernel doesn't find a rootfs.

It seems like the compressed initramfs is corrupted somehow, since "rootfs
image is not initramfs" doesn't appear on a successful boot.

initramfs and kernel are loaded via direct kernel boot. Running under KVM.

Some vhost error messages do appear before the guest panics, but it is not
entirely clear to me whether they are related:

  [...]
  2024-08-28T06:56:29.765324Z qemu-system-s390x: vhost vring error in virtqueue 
0: Invalid argument (22)
  2024-08-28T06:56:32.210982Z qemu-system-s390x: vhost vring error in virtqueue 
0: Invalid argument (22)
  2024-08-28 06:56:35.430+0000: panic s390: core='0' 
psw-mask='0x0002000180000000' psw-addr='0x00000387b028c67e' 
reason='disabled-wait'

Any idea?