| From jejb@kernel.org Wed Oct 15 14:42:49 2008 |
| From: Alan Cox <alan@redhat.com> |
| Date: Sun, 12 Oct 2008 19:40:08 GMT |
| Subject: x86, early_ioremap: fix fencepost error |
| To: jejb@kernel.org, stable@kernel.org |
| Message-ID: <200810121940.m9CJe8k3024539@hera.kernel.org> |
| |
| From: Alan Cox <alan@redhat.com> |
| |
| commit c613ec1a7ff3714da11c7c48a13bab03beb5c376 upstream |
| |
| The x86 implementation of early_ioremap has an off by one error. If we get |
| an object which ends on the first byte of a page we undermap by one page and |
| this causes a crash on boot with the ASUS P5QL whose DMI table happens to fit |
| this alignment. |
| |
| The size computation is currently |
| |
| last_addr = phys_addr + size - 1; |
| npages = (PAGE_ALIGN(last_addr) - phys_addr) |
| |
| (Consider a request for 1 byte at alignment 0...) |
| |
| Closes #11693 |
| |
| Debugging work by Ian Campbell/Felix Geyer |
| |
| Signed-off-by: Alan Cox <alan@rehat.com> |
| Signed-off-by: Ingo Molnar <mingo@elte.hu> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| arch/x86/mm/ioremap.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/arch/x86/mm/ioremap.c |
| +++ b/arch/x86/mm/ioremap.c |
| @@ -595,7 +595,7 @@ void __init *early_ioremap(unsigned long |
| */ |
| offset = phys_addr & ~PAGE_MASK; |
| phys_addr &= PAGE_MASK; |
| - size = PAGE_ALIGN(last_addr) - phys_addr; |
| + size = PAGE_ALIGN(last_addr + 1) - phys_addr; |
| |
| /* |
| * Mappings have to fit in the FIX_BTMAP area. |
