[PATCH RT] don't BUG_ON in exit for in_interrupt

For some reason, in the RT kernel, we have in exit.c a
BUG_ON(in_interrupt()) just before a check of in_interrupt() then panic.
With the panic, we get a nice output of what happened (considering that
the panic gives us a backtrace).

But a BUG_ON will cause a fault, and then try to bug again. This causes
a recursive fault which eventually eats up the stack.  Twice have we
lost information on a crash because of this recursive faulting.

This patch undoes the adding the BUG_ON in exit.c.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Index: linux-2.6.21.5-rt17/kernel/exit.c
===================================================================

--- linux-2.6.21.5-rt17.orig/kernel/exit.c
+++ linux-2.6.21.5-rt17/kernel/exit.c

@@ -863,7 +863,6 @@ fastcall NORET_TYPE void do_exit(long co
 
 	WARN_ON(atomic_read(&tsk->fs_excl));
 
-	BUG_ON(in_interrupt());
 	if (unlikely(in_interrupt()))
 		panic("Aiee, killing interrupt handler!");
 	if (unlikely(!tsk->pid))