[IA64] kprobes: fixup the pagefault exception caused by probehandlers

If the user-specified kprobe handler causes the page fault when accessing
user space address, fixup this fault since do_page_fault() should not
continue as the kprobe handler are run with preemption disabled.
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

arch/ia64/kernel/kprobes.c

@@ -771,6 +771,12 @@ static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
 		 */
 		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 			return 1;
+		/*
+		 * In case the user-specified fault handler returned
+		 * zero, try to fix up.
+		 */
+		if (ia64_done_with_exception(regs))
+			return 1;
 
 		/*
 		 * Let ia64_do_page_fault() fix it.