Re: Problems starting Xen domU after latest stable update

[Michael Labriola <michael.d.labriola@xxxxxxxxx>]

On Fri, Jan 29, 2021 at 12:26 AM Jürgen Groß <jgross@xxxxxxxx> wrote:
>
> On 29.01.21 01:51, Marek Marczykowski-Górecki wrote:
> > On Thu, Jan 28, 2021 at 07:03:00PM -0500, Boris Ostrovsky wrote:
> >>
> >> On 1/28/21 6:52 PM, Michael D Labriola wrote:
> >>> Hey, everyone.  I've run into problems starting up my Xen domUs as of
> >>> the latest batch of stable updates.  Whenever I try to create one, I
> >>> get a bunch of block device errors like this:
> >>>
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to add device with path /local/domain/0/backend/vbd/4/51712
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to add device with path /local/domain/0/backend/vbd/4/51728
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to add device with path /local/domain/0/backend/vbd/4/51744
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to add device with path /local/domain/0/backend/vbd/4/51760
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to add device with path /local/domain/0/backend/vbd/4/51776
> >>> libxl: error: libxl_create.c:1452:domcreate_launch_dm: Domain 4:unable to 
> >>> add disk devices
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to remove device with path /local/domain/0/backend/vbd/4/51712
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to remove device with path /local/domain/0/backend/vbd/4/51728
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to remove device with path /local/domain/0/backend/vbd/4/51744
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to remove device with path /local/domain/0/backend/vbd/4/51760
> >>> libxl: error: libxl_device.c:1105:device_backend_callback: Domain 
> >>> 4:unable to remove device with path /local/domain/0/backend/vbd/4/51776
> >>> libxl: error: libxl_domain.c:1290:devices_destroy_cb: Domain 
> >>> 4:libxl__devices_destroy failed
> >>> libxl: error: libxl_domain.c:1177:libxl__destroy_domid: Domain 
> >>> 4:Non-existant domain
> >>> libxl: error: libxl_domain.c:1131:domain_destroy_callback: Domain 
> >>> 4:Unable to destroy guest
> >>> libxl: error: libxl_domain.c:1058:domain_destroy_cb: Domain 4:Destruction 
> >>> of domain failed
> >>>
> >>> I'm using Xen 4.13.1 on the box I've been testing with.
> >>>
> >>> I bisected down to this commit, and reverting it does indeed fix my
> >>> problem.  Well, this commit upstream and it's cherry-picked variants
> >>> on linux-5.4.y and linux-5.10.y.
> >>
> >>
> >> You most likely need 5f46400f7a6a4fad635d5a79e2aa5a04a30ffea1. It hit 
> >> Linus tree a few hours ago.
> >
> > I can confirm this fixes the same issue for me (too?), thanks!
> > Shouldn't this patch have Cc: stable?
>
> No, I don't think so.
>
> The issue being fixed by the patch has been introduced only in 5.11

For the record, the issue is also in the latest stable 5.4.y and
5.10.y releases (I assume older ones as well, but those are the only 2
I tested).  That's where I ran into it initially.

> and the fixing patch references the buggy patch via a Fixes: tag.
>
> If the buggy patch has been put into stable this Fixes: tag should
> result in the fix being put into the same stable branches as well.

I've never done this before...  does this happen automatically?  Or is
there somebody we should ping to make sure it happens?

Thanks!

-Mike