diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 6510e13a4878..bb25d17977fc 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -701,8 +701,9 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options,
 	 */
 	if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
 		PROC_LOCK(p);
-		p->p_oppid = 0;
 		proc_reparent(p, t);
+		p->p_pptr->p_dbg_child--;
+		p->p_oppid = 0;
 		PROC_UNLOCK(p);
 		pksignal(t, SIGCHLD, p->p_ksi);
 		wakeup(t);
@@ -794,7 +795,8 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
 		pid = -q->p_pgid;
 		PROC_UNLOCK(q);
 	}
-	if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
+	/* If we don't know the option, just return. */
+	if (options & ~(WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
 		return (EINVAL);
 loop:
 	if (q->p_flag & P_STATCHILD) {
@@ -873,7 +875,10 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
 	}
 	if (nfound == 0) {
 		sx_xunlock(&proctree_lock);
-		return (ECHILD);
+		if (td->td_proc->p_dbg_child)
+			return (0);
+		else
+			return (ECHILD);
 	}
 	if (options & WNOHANG) {
 		sx_xunlock(&proctree_lock);
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index a7f280a0410e..a4c0069bcf8c 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -831,8 +831,11 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 		/* security check done above */
 		p->p_flag |= P_TRACED;
 		p->p_oppid = p->p_pptr->p_pid;
-		if (p->p_pptr != td->td_proc)
+		if (p->p_pptr != td->td_proc) {
+			/* Remember that a child is being debugged(traced). */
+			p->p_pptr->p_dbg_child++;
 			proc_reparent(p, td->td_proc);
+		}
 		data = SIGSTOP;
 		goto sendsig;	/* in PT_CONTINUE below */
 
@@ -919,11 +922,12 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 					PROC_UNLOCK(pp);
 				PROC_LOCK(p);
 				proc_reparent(p, pp);
+				p->p_pptr->p_dbg_child--;
 				if (pp == initproc)
 					p->p_sigparent = SIGCHLD;
 			}
-			p->p_flag &= ~(P_TRACED | P_WAITED | P_FOLLOWFORK);
 			p->p_oppid = 0;
+			p->p_flag &= ~(P_TRACED | P_WAITED | P_FOLLOWFORK);
 
 			/* should we send SIGCHLD? */
 			/* childproc_continued(p); */
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 4d7b540c2e6b..c54a95699e2e 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -503,6 +503,8 @@ struct proc {
 /* The following fields are all zeroed upon creation in fork. */
 #define	p_startzero	p_oppid
 	pid_t		p_oppid;	/* (c + e) Save ppid in ptrace. XXX */
+	int		p_dbg_child;	/* (c + e) # of debugged children in
+							ptrace. */
 	struct vmspace	*p_vmspace;	/* (b) Address space. */
 	u_int		p_swtick;	/* (c) Tick when swapped in or out. */
 	struct itimerval p_realtimer;	/* (c) Alarm timer. */