[IA64] page_not_present fault in region 5 is normal
Kiyoshi Ueda [Wed, 24 Aug 2005 22:03:43 +0000 (18:03 -0400)]
When copying data from user-space to kernel-space by __copy_user(),
a page_not_present fault sometimes occurs at vmalloced kernel address
because of VHPT pre-fetching.

Ignore the page_not_present fault in ia64_do_page_fault() before
jumping into exception handlers.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/fault.c

index ff62551..839d4f1 100644 (file)
@@ -229,9 +229,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
                return;
        }
 
-       if (ia64_done_with_exception(regs))
-               return;
-
        /*
         * Since we have no vma's for region 5, we might get here even if the address is
         * valid, due to the VHPT walker inserting a non present translation that becomes
@@ -242,6 +239,9 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
        if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
                return;
 
+       if (ia64_done_with_exception(regs))
+               return;
+
        /*
         * Oops. The kernel tried to access some bad page. We'll have to terminate things
         * with extreme prejudice.