diff -Nar -U4 linux-2.6.9-rc4/kernel/fork.c new/kernel/fork.c
--- linux-2.6.9-rc4/kernel/fork.c	2004-10-12 16:18:03.661895647 -0700
+++ new/kernel/fork.c	2004-10-12 15:59:14.287779998 -0700
@@ -1145,9 +1145,10 @@
 
 bad_fork_cleanup_namespace:
 	exit_namespace(p);
 bad_fork_cleanup_mm:
-	mmput(p->mm);
+	if (p->mm)
+		mmput(p->mm);
 bad_fork_cleanup_signal:
 	exit_signal(p);
 bad_fork_cleanup_sighand:
 	exit_sighand(p);