Re: fix off-by-one error in ioremap()

[Arjan van de Ven <arjanv@redhat.com>]

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On Fri, 2003-09-12 at 10:15, Linux Kernel Mailing List wrote:
> ChangeSet 1.1063.43.5, 2003/09/12 04:15:36-04:00, len.brown@intel.com
> 
> 	fix off-by-one error in ioremap()
> 	fixes kernel crash in acpi mode: http://bugzilla.kernel.org/show_bug.cgi?id=1085

> diff -Nru a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
> --- a/arch/i386/mm/ioremap.c	Wed Sep 17 14:07:31 2003
> +++ b/arch/i386/mm/ioremap.c	Wed Sep 17 14:07:31 2003
> @@ -140,7 +140,7 @@
>  	 */
>  	offset = phys_addr & ~PAGE_MASK;
>  	phys_addr &= PAGE_MASK;
> -	size = PAGE_ALIGN(last_addr) - phys_addr;
> +	size = PAGE_ALIGN(last_addr+1) - phys_addr;
>  


A bit higher in that function is:
                                                                                                        
        /* Don't allow wraparound or zero size */
        last_addr = phys_addr + size - 1;
        if (!size || last_addr < phys_addr)
                return NULL;
                                                                                                        

so why do you undo the deliberate -1 there ?

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