Re: [patch 071/149] ARM: 6166/1: Proper prefetch abort handling on pre-ARMv6

Kirill A. Shutemov
2010-07-01T22:14:42Z

On Thu, Jul 01, 2010 at 10:31:37AM -0700, Greg KH wrote:
> 2.6.32-stable review patch. If anyone has any objections, please let us know.
>
> ------------------
>
> From: Anfei <anfei.zhou@gmail.com>
>
> commit 5e27fb78df95e027723af2c90ecc9b4527ae59e9 upstream.
>
> Instruction faults on pre-ARMv6 CPUs are interpreted as
> a 'translation fault', but do_translation_fault doesn't
> handle well if user mode trying to run instruction above
> TASK_SIZE, and result in the infinite retry of that
> instruction.

Actually, this patch helps also on ARMv6+. Probably, better to correct
commit message for stable.

> Signed-off-by: Anfei Zhou <anfei.zhou@gmail.com>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
>
> ---
> arch/arm/mm/fault.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> --- a/arch/arm/mm/fault.c
> +++ b/arch/arm/mm/fault.c
> @@ -386,6 +386,9 @@ do_translation_fault(unsigned long addr,
> if (addr < TASK_SIZE)
> return do_page_fault(addr, fsr, regs);
>
> + if (user_mode(regs))
> + goto bad_area;
> +
> index = pgd_index(addr);
>
> /*
>
>
> --
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--
Kirill A. Shutemov