From: Zwane Mwaikambo <zwane@arm.linux.org.uk>
The 4G/4G page fault handling path doesn't appear to handle faults
happening whilst in vm86. The regs->xcs != __USER_CS so it confused the in
kernel test.
However i'm still debugging the X11 triple fault in test9-mm3
Unable to handle kernel paging request at virtual address 00002000
printing eip:
00007341
*pde = 00000000
Oops: 0004 [#1]
SMP DEBUG_PAGEALLOC
CPU: 0
EIP: c000:[<00007341>] Not tainted VLI
EFLAGS: 00033246
EIP is at 0x7341
eax: 32454256 ebx: 00000000 ecx: 00000000 edx: 00000000
esi: 00000000 edi: 00002000 ebp: 00000fd6 esp: 087bbf24
ds: 0000 es: 0000 ss: 0068
Process X (pid: 939, threadinfo=087ba000 task=0891c690)
Stack: 00000fcb 00000100 00000000 0000c000 00000000 00000000 00000000 00000000
00000005 ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
Call Trace:
arch/i386/mm/fault.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletion(-)
diff -puN arch/i386/mm/fault.c~4g4g-vm86-fix arch/i386/mm/fault.c
--- 25/arch/i386/mm/fault.c~4g4g-vm86-fix 2003-11-15 13:32:10.000000000 -0800
+++ 25-akpm/arch/i386/mm/fault.c 2003-11-15 13:32:10.000000000 -0800
@@ -264,7 +264,9 @@ asmlinkage void do_page_fault(struct pt_
if (error_code & 3)
goto bad_area_nosemaphore;
- goto vmalloc_fault;
+ /* If it's vm86 fall through */
+ if (!(regs->eflags & VM_MASK))
+ goto vmalloc_fault;
}
#else
if (unlikely(address >= TASK_SIZE)) {
_