Re: [PATCH] xen: arm: Don't use stop_cpu() in halt_this_cpu()

[Julien Grall <julien@xxxxxxx>]

Hi Stefano,

On 28/06/2022 23:56, Stefano Stabellini wrote:
> > The advantage of the panic() is it will remind us that some needs to be fixed.
> > With a warning (or WARN()) people will tend to ignore it.
> I know that this specific code path (cpu off) is probably not super
> relevant for what I am about to say, but as we move closer to safety
> certifiability we need to get away from using "panic" and BUG_ON as a
> reminder that more work is needed to have a fully correct implementation
> of something.
I don't think we have many places at runtime using BUG_ON()/panic(). 
They are often used because we think Xen would not be able to recover if 
the condition is hit.
I am happy to remove them, but this should not be at the expense to 
introduce other potential weird bugs.
> I also see your point and agree that ASSERT is not acceptable for
> external input but from my point of view panic is the same (slightly
> worse because it doesn't go away in production builds).
I think it depends on your target. Would you be happy if Xen continue to 
run with potentially a fatal flaw?
> Julien if you are going to ack the patch feel free to go ahead.
I will do and commit it.

Cheers,

--
Julien Grall