Subject: Re: PTP vclock: BUG: scheduling while atomic

From: Miroslav Lichvar <[email-masked]>
Date: Thu, 2 Feb 2023 17:33:15 +0100

On Thu, Feb 02, 2023 at 05:02:07PM +0100, Íñigo Huguet wrote:
> Our QA team was testing PTP vclocks, and they've found this error with sfc NIC/driver:
>   BUG: scheduling while atomic: ptp5/25223/0x00000002
> 
> The reason seems to be that vclocks disable interrupts with `spin_lock_irqsave` in
> `ptp_vclock_gettime`, and then read the timecounter, which in turns ends calling to
> the driver's `gettime64` callback.

The same issue was observed with the ice driver:
https://lists.osuosl.org/pipermail/intel-wired-lan/Week-of-Mon-20221107/030633.html

I tried to fix it generally in the vclock support, but was not
successful. There was a hint it would be fixed in the driver. I'm not
sure what is the best approach here.

-- 
Miroslav Lichvar