Index: kernel/generic/src/main/uinit.c
===================================================================
--- kernel/generic/src/main/uinit.c	(revision ac47b7c2b6e75a9b9aa60b443fca9a151cf89e5c)
+++ kernel/generic/src/main/uinit.c	(revision 84683fdcff89e57c1a5b8126534bdef325411961)
@@ -80,4 +80,12 @@
 
 	free((uspace_arg_t *) arg);
+	
+	/*
+	 * Disable interrupts so that the execution of userspace() is not
+	 * disturbed by any interrupts as some of the userspace()
+	 * implementations will switch to the userspace stack before switching
+	 * the mode.
+	 */
+	(void) interrupts_disable();
 	userspace(&uarg);
 }