Index: kernel/generic/src/main/uinit.c
===================================================================
--- kernel/generic/src/main/uinit.c	(revision ec8b0dac0a89d85fb1256e7e6a702141cc630506)
+++ kernel/generic/src/main/uinit.c	(revision 9a61ba5ab896f13e7e633f8d52af72325669aaf6)
@@ -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);
 }