Re: [PATCH v2] x86/ioremap: Use is_ioremap_addr() in iounmap()

Thomas Gleixner
2024-08-14T14:11:37Z

On Wed, Aug 14 2024 at 05:16, Christoph Hellwig wrote:
> On Wed, Aug 14, 2024 at 10:08:23PM +1000, Alistair Popple wrote:
>> I would tend to agree and had the same thought when we found this. At
>> least some kind of message (WARN_ON, WARN_ON_ONCE, printk, etc) would
>> have made the issue we were debugging much more obvious. FWIW I have
>> tested running with a WARN_ON() there and it never fired except in the
>> bug scenario.
>
> Various architectures had either an early ioremap variant that got
> silently ignored here, or magic carveout that don't get remapped at all.
> None of this should currently apply to x86, though.

So I'm inclined to have:

if (WARN_ON_ONCE(is_ioremap_addr(addr)))
return;

in the x86 variant then.

Thanks,

tglx