[patch 03/14] x86, early_ioremap: fix fencepost error
From: Greg KH
Date: Sat Oct 18 2008 - 15:20:50 EST
2.6.25-stable review patch. If anyone has any objections, please let us
know.
------------------
From: Alan Cox <alan@xxxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
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
@@ -438,7 +438,7 @@ 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.
--
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