Re: [patch v3 30/36] Hexagon: Add page-fault support.

Benjamin Herrenschmidt
2011-09-11T15:08:49Z

On Thu, 2011-09-08 at 20:09 -0500, Richard Kuo wrote:

> +/*
> + * Canonical page fault handler
> + */
> +void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
> +{
> + struct vm_area_struct *vma;
> + struct mm_struct *mm = current->mm;
> + siginfo_t info;
> + int si_code;
> + int fault;
> + const struct exception_table_entry *fixup;
> +
> + si_code = SEGV_MAPERR;
> + local_irq_enable();
> +
> + /*
> + * If we're in an interrupt or have no user context,
> + * then must not take the fault.
> + */
> + if (unlikely(in_interrupt() || !mm))
> + goto no_context;

Are you sure about enabling interrupts before going to "no_context" ?

If somebody does a user access "in atomic" with interrupt disabled (with
the expectation that a fault would be caught by search_exception_tables
and returned as -EFAULT), such code probably doesn't expect interrupts
to be re-enabled implicitely.

Cheers,
Ben.