Re: [PATCH 1/1] EFI iounpam fix for acpi_os_unmap_memory

[Andrew Morton]

Andi Kleen <ak@xxxxxxx> wrote:
>
> Andrew Morton <akpm@xxxxxxxx> writes:
> 
> >  
> >  void acpi_os_unmap_memory(void __iomem * virt, acpi_size size)
> >  {
> > +	/* Don't unmap memory which was not mapped by acpi_os_map_memory */
> > +	if (efi_enabled &&
> > +	    (efi_mem_attributes(virt_to_phys(virt)) & EFI_MEMORY_WB))
> > +		return;
> 
> 
> The patch is wrong because if the address came from ioremap 
> virt_to_phys doesn't give the real physical address. Also looking
> at acpi_os_map_memory it doesn't quite match the logic there.
> 
> One working way to check for ioremap memory is 
> virt >= VMALLOC_START  && virt < VMALLOC_END
> 

OK, thanks.  I don't think we actually know who is trying to unmap some
memory which acpi didn't map.

Edgar, can you please describe the bug which you're trying to fix?
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