Re: [PATCH] virtio: use virtio_device_ready() in virtio_device_restore()

[Jason Wang]

On Wed, Mar 23, 2022 at 4:04 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> On Wed, Mar 23, 2022 at 11:10:27AM +0800, Jason Wang wrote:
> >On Tue, Mar 22, 2022 at 10:07 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
> >>
> >> On Tue, Mar 22, 2022 at 12:43:13PM +0100, Stefano Garzarella wrote:
> >> > After waking up a suspended VM, the kernel prints the following trace
> >> > for virtio drivers which do not directly call virtio_device_ready() in
> >> > the .restore:
> >> >
> >> >     PM: suspend exit
> >> >     irq 22: nobody cared (try booting with the "irqpoll" option)
> >> >     Call Trace:
> >> >      <IRQ>
> >> >      dump_stack_lvl+0x38/0x49
> >> >      dump_stack+0x10/0x12
> >> >      __report_bad_irq+0x3a/0xaf
> >> >      note_interrupt.cold+0xb/0x60
> >> >      handle_irq_event+0x71/0x80
> >> >      handle_fasteoi_irq+0x95/0x1e0
> >> >      __common_interrupt+0x6b/0x110
> >> >      common_interrupt+0x63/0xe0
> >> >      asm_common_interrupt+0x1e/0x40
> >> >      ? __do_softirq+0x75/0x2f3
> >> >      irq_exit_rcu+0x93/0xe0
> >> >      sysvec_apic_timer_interrupt+0xac/0xd0
> >> >      </IRQ>
> >> >      <TASK>
> >> >      asm_sysvec_apic_timer_interrupt+0x12/0x20
> >> >      arch_cpu_idle+0x12/0x20
> >> >      default_idle_call+0x39/0xf0
> >> >      do_idle+0x1b5/0x210
> >> >      cpu_startup_entry+0x20/0x30
> >> >      start_secondary+0xf3/0x100
> >> >      secondary_startup_64_no_verify+0xc3/0xcb
> >> >      </TASK>
> >> >     handlers:
> >> >     [<000000008f9bac49>] vp_interrupt
> >> >     [<000000008f9bac49>] vp_interrupt
> >> >     Disabling IRQ #22
> >> >
> >> > This happens because we don't invoke .enable_cbs callback in
> >> > virtio_device_restore(). That callback is used by some transports
> >> > (e.g. virtio-pci) to enable interrupts.
> >> >
> >> > Let's fix it, by calling virtio_device_ready() as we do in
> >> > virtio_dev_probe(). This function calls .enable_cts callback and sets
> >> > DRIVER_OK status bit.
> >> >
> >> > This fix also avoids setting DRIVER_OK twice for those drivers that
> >> > call virtio_device_ready() in the .restore.
> >> >
> >> > Fixes: d50497eb4e55 ("virtio_config: introduce a new .enable_cbs method")
> >> > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> >> > ---
> >> >
> >> > I'm not sure about the fixes tag. That one is more generic, but the
> >> > following one I think introduced the issue.
> >> >
> >> > Fixes: 9e35276a5344 ("virtio_pci: harden MSI-X interrupts")
> >>
> >> Jason what should we do about this one BTW? Just revert? We have other
> >> issues ...
> >
> >Let me post a patch to revert it and give it a rework.
>
> Thanks for reverting it.
>
> Should we queue this patch anyway to prevent future issues and avoid
> setting DRIVER_OK twice?
>
> Please, let me know if I have to resend it by removing the call trace
> that after the revert should no longer occur.

I think we can have another version.

Thanks

>
> Thanks,
> Stefano
>