Re: [PATCH v2] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes

From: Michael Chan
Date: Mon Jul 27 2020 - 03:26:36 EST

On Fri, Jul 24, 2020 at 5:19 PM David Christensen
<drc@xxxxxxxxxxxxxxxxxx> wrote:

> In the working case, tg3_init_hw() returns successfully, resulting in
> every instance of napi_disable() being followed by an instance of
> napi_enable().
> In the failing case, tg3_hw_init() returns an error. (This is not
> surprising since the system is now preventing the adapter from accessing
> its MMIO registers. I'm curious why it doesn't always fail.) When
> tg3_hw_init() fails, tg3_netif_start() is not called, and we end up with
> two sequential calls to napi_disable(), resulting in multiple hung task
> messages.

If the driver fails to initialize the chip completely, the tg3_flags
should indicate we are in this failed state. We already have
TG3_FLAG_INIT_COMPLETE. Perhaps, we can expand the use of this flag
to cover the scenario that you described above. We can clear
TG3_FLAG_INIT_COMPLETE before calling tg3_halt() and only set it back
when tg3_hw_init() completes successfully. This is the rough idea,
but a more detailed analysis on how this flag is used needs to be done

Assuming this works, the EEH handler can check TG3_FLAG_INIT_COMPLETE
to see if we should call tg3_netif_stop().

Another way to fix it is to call dev_close() if tg3_reset_task() fails
to re-initialize the device.