Re: crash in entry.S restore_all, 2.6.12-rc2, x86, PAGEALLOC

[Andrew Morton]

Ingo Molnar <mingo@xxxxxxx> wrote:
>
> the crashes below happen when PAGEALLOC is enabled. It's this 
>  instruction:
> 
>          movb OLDSS(%esp), %ah
> 
>  OLDSS is 0x38, esp is f4f83fc8, OLDSS(%esp) is thus f4f84000, which 
>  correctly creates the PAGEALLOC pagefault. esp is off by 4 bytes?
> 
>  it could be the ESP-16-bit-corruption patch causing this,

Do you have nmis enabled?



From: Akinobu Mita <amgta@xxxxxxxxxxxxxxx>

With nmi_watchdog=1, I got random Oopses (Unable to handle kernel paging
request, not by the NMI oopser) from many processes.  It is not happend
with -rc1.

The following change fixes this problem.

Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 25-akpm/arch/i386/kernel/entry.S |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN arch/i386/kernel/entry.S~nmi_stack_correct-fix arch/i386/kernel/entry.S
--- 25/arch/i386/kernel/entry.S~nmi_stack_correct-fix	2005-04-05 00:02:48.000000000 -0700
+++ 25-akpm/arch/i386/kernel/entry.S	2005-04-05 00:02:48.000000000 -0700
@@ -550,7 +550,7 @@ nmi_stack_correct:
 	xorl %edx,%edx		# zero error code
 	movl %esp,%eax		# pt_regs pointer
 	call do_nmi
-	jmp restore_all
+	jmp restore_nocheck
 
 nmi_stack_fixup:
 	FIX_STACK(12,nmi_stack_correct, 1)
_

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