diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 52f68f07d7ec..917de57ca742 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -208,7 +208,6 @@ fork1(td, flags, pages, procp)
 	 * certain parts of a process from itself.
 	 */
 	if ((flags & RFPROC) == 0) {
-#if 0 /* XXX no other OS tries to do this */
 		if (((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) &&
 		    (flags & (RFCFDG | RFFDG))) {
 			PROC_LOCK(p1);
@@ -218,7 +217,6 @@ fork1(td, flags, pages, procp)
 			}
 			PROC_UNLOCK(p1);
 		}
-#endif
 
 		vm_forkproc(td, NULL, NULL, flags);
 
@@ -238,49 +236,21 @@ fork1(td, flags, pages, procp)
 		if (flags & RFFDG) 
 			fdunshare(p1, td);
 
-#if 0 /* XXX no other OS tries to do this */
 		if (((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) &&
 		    (flags & (RFCFDG | RFFDG))) {
 			PROC_LOCK(p1);
 			thread_single_end();
 			PROC_UNLOCK(p1);
 		}
-#endif
 		*procp = NULL;
 		return (0);
 	}
 
-#if 0 /* XXX no other OS tries to do this */
 	/*
-	 * Note 1:1 allows for forking with one thread coming out on the
-	 * other side with the expectation that the process is about to
-	 * exec.
+	 * XXX
+	 * We did have single-threading code here
+	 * however it proved un-needed and caused problems
 	 */
-	if ((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) {
-		/*
-		 * Systems processes don't need this.
-		 * Idle the other threads for a second.
-		 * Since the user space is copied, it must remain stable.
-		 * In addition, all threads (from the user perspective)
-		 * need to either be suspended or in the kernel,
-		 * where they will try restart in the parent and will
-		 * be aborted in the child.
-		 * keep threadds at the boundary there.
-		 */
-		PROC_LOCK(p1);
-		if (thread_single(SINGLE_BOUNDARY)) {
-			/* Abort. Someone else is single threading before us. */
-			PROC_UNLOCK(p1);
-			return (ERESTART);
-		}
-		PROC_UNLOCK(p1);
-		/*
-		 * All other activity in this process
-		 * is now suspended at the user boundary,
-		 * (or other safe places if we think of any).
-		 */
-	}
-#endif
 
 	/* Allocate new proc. */
 	newproc = uma_zalloc(proc_zone, M_WAITOK);
@@ -729,17 +699,6 @@ fork1(td, flags, pages, procp)
 		msleep(p1, &p2->p_mtx, PWAIT, "ppwait", 0);
 	PROC_UNLOCK(p2);
 
-#if 0 /* XXX no other OS tries to do this */
-	/*
-	 * If other threads are waiting, let them continue now.
-	 */
-	if ((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) {
-		PROC_LOCK(p1);
-		thread_single_end();
-		PROC_UNLOCK(p1);
-	}
-
-#endif
 	/*
 	 * Return child proc pointer to parent.
 	 */
@@ -755,11 +714,6 @@ fork1(td, flags, pages, procp)
 	mac_proc_destroy(newproc);
 #endif
 	uma_zfree(proc_zone, newproc);
-	if (p1->p_flag & P_HADTHREADS) {
-		PROC_LOCK(p1);
-		thread_single_end();
-		PROC_UNLOCK(p1);
-	}
 	pause("fork", hz / 2);
 	return (error);
 }