Re: [PATCH] virtio: Remove virtio devices on device_shutdown()

[Jiri Pirko]

Thu, Aug 08, 2024 at 02:11:09PM CEST, kirill.shutemov@xxxxxxxxxxxxxxx wrote:
>On Thu, Aug 08, 2024 at 01:37:42PM +0200, Jiri Pirko wrote:
>> Thu, Aug 08, 2024 at 09:51:41AM CEST, kirill.shutemov@xxxxxxxxxxxxxxx wrote:
>> >Hongyu reported a hang on kexec in a VM. QEMU reported invalid memory
>> >accesses during the hang.
>> >
>> >	Invalid read at addr 0x102877002, size 2, region '(null)', reason: rejected
>> >	Invalid write at addr 0x102877A44, size 2, region '(null)', reason: rejected
>> >	...
>> >
>> >It was traced down to virtio-console. Kexec works fine if virtio-console
>> >is not in use.
>> >
>> >Looks like virtio-console continues to write to the MMIO even after
>> >underlying virtio-pci device is removed.
>> >
>> >The problem can be mitigated by removing all virtio devices on virtio
>> >bus shutdown.
>> >
>> >Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
>> >Reported-by: Hongyu Ning <hongyu.ning@xxxxxxxxxxxxxxx>
>> 
>> Could you provide a "Fixes:" tag pointing to the commit that introduced
>> the bug?
>
>I am not sure if it is a regression. Maybe it was there forever.

Does not have to be regression. You can blame the commit that added the
code.


>
>Hongyu, could you please check with bisect if it is possible to point to a
>specific commit?
>
>-- 
>  Kiryl Shutsemau / Kirill A. Shutemov