Re: Questions: Should kernel panic when PCIe fatal error occurs?

Oliver O'Halloran
2023-09-25T03:54:21Z

On Fri, Sep 22, 2023 at 8:23 AM David Laight <David.Laight@aculab.com> wrote:
>
> > It would be nice if they worked the same, but I suspect that vendors
> > may rely on the fact that CPER_SEV_FATAL forces a restart/panic as
> > part of their system integrity story.
>
> The file system errors created by a panic (especially an NMI panic)
> could easily be more problematic than a failed PCIe data transfer.
> Evan a read that returned ~0u - which can be checked for.
>
> Panicking a system that is converting TDM telephony to RTP for the
> 911 emergency service because a PCIe cable/riser connecting one of the
> TDM board has become loose doesn't seem ideal.

For kernel native AER the default reaction to errors is
reset-and-reinit which probably isn't much better for your case.
Sounds like you would want a knob to suppress everything except error
reporting so you can handle it in userspace?

> (Or because the TDM board's fpga has decided it isn't going to respond
> to any accesses until the BARs are setup again...)
>
> The system can carry on with some TDM connections disabled - but that
> is ok because they are all duplicated in case a cable gets cuit.

Well that's a relief :)

Oliver