--- arch/x86/kernel/signal.c.orig	2012-03-08 11:18:19.702651943 +0100
+++ arch/x86/kernel/signal.c	2012-03-08 10:31:18.682304346 +0100
@@ -765,8 +765,11 @@ static void do_signal(struct pt_regs *re
 	 * X86_32: vm86 regs switched out by assembly code before reaching
 	 * here, so testing against kernel CS suffices.
 	 */
-	if (!user_mode(regs))
+	if (!user_mode(regs)) {
+		printk(KERN_EMERG "* endless loop\n");
+		dump_stack();
 		return;
+	}
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {