[PATCH 3.11 071/233] x86/efi: Fix off-by-one bug in EFI Boot Services reservation

Luis Henriques luis.henriques at canonical.com
Fri Feb 7 11:44:50 UTC 2014


3.11.10.4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Young <dyoung at redhat.com>

commit a7f84f03f660d93574ac88835d056c0d6468aebe upstream.

Current code check boot service region with kernel text region by:
start+size >= __pa_symbol(_text)
The end of the above region should be start + size - 1 instead.

I see this problem in ovmf + Fedora 19 grub boot:
text start: 1000000 md start: 800000 md size: 800000

Signed-off-by: Dave Young <dyoung at redhat.com>
Acked-by: Borislav Petkov <bp at suse.de>
Acked-by: Toshi Kani <toshi.kani at hp.com>
Tested-by: Toshi Kani <toshi.kani at hp.com>
Signed-off-by: Matt Fleming <matt.fleming at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/x86/platform/efi/efi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 220fa52..f19284d 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -440,7 +440,7 @@ void __init efi_reserve_boot_services(void)
 		 * - Not within any part of the kernel
 		 * - Not the bios reserved area
 		*/
-		if ((start+size >= __pa_symbol(_text)
+		if ((start + size > __pa_symbol(_text)
 				&& start <= __pa_symbol(_end)) ||
 			!e820_all_mapped(start, start+size, E820_RAM) ||
 			memblock_is_region_reserved(start, size)) {
-- 
1.8.3.2





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