Re: [PATCH 00 of 36] x86/paravirt: groundwork for 64-bit Xen support

[Jeremy Fitzhardinge]

Ingo Molnar wrote:
> that fixed the build but now we've got a boot crash with this config:
>
>  time.c: Detected 2010.304 MHz processor.
>  spurious 8259A interrupt: IRQ7.
>  BUG: unable to handle kernel NULL pointer dereference at  0000000000000000
>  IP: [<0000000000000000>]
>  PGD 0
>  Thread overran stack, or stack corrupted
>  Oops: 0010 [1] SMP
>  CPU 0
>   

I don't know if this will fix this bug, but it's definitely a bugfix.  
It was trashing random pages by overwriting them with pagetables...

Subject: x86_64: memory mapping: don't trash large pmd mapping

Don't trash a large pmd's data when mapping physical memory.
This is a bugfix for "x86_64: adjust mapping of physical pagetables
to work with Xen".

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/mm/init_64.c |    3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

===================================================================
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -311,7 +311,8 @@
		}

		if (pmd_val(*pmd)) {
-			phys_pte_update(pmd, address, end);
+			if (!pmd_large(*pmd))
+				phys_pte_update(pmd, address, end);
			continue;
		}



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/