Index: sys/fs/fifofs/fifo_vnops.c
===================================================================
--- sys/fs/fifofs/fifo_vnops.c
+++ sys/fs/fifofs/fifo_vnops.c
@@ -174,8 +174,10 @@
 		fip->fi_rgen++;
 		if (fip->fi_readers == 1) {
 			fpipe->pipe_state &= ~PIPE_EOF;
-			if (fip->fi_writers > 0)
+			if (fip->fi_writers > 0) {
 				wakeup(&fip->fi_writers);
+				pipeselwakeup(fpipe);
+			}
 		}
 		fp->f_pipegen = fpipe->pipe_wgen - fip->fi_writers;
 	}
@@ -190,8 +192,10 @@
 		fip->fi_wgen++;
 		if (fip->fi_writers == 1) {
 			fpipe->pipe_state &= ~PIPE_EOF;
-			if (fip->fi_readers > 0)
+			if (fip->fi_readers > 0) {
 				wakeup(&fip->fi_readers);
+				pipeselwakeup(fpipe);
+			}
 		}
 	}
 	if ((ap->a_mode & O_NONBLOCK) == 0) {
@@ -210,6 +214,7 @@
 					fpipe->pipe_state |= PIPE_EOF;
 					if (fpipe->pipe_state & PIPE_WANTW)
 						wakeup(fpipe);
+					pipeselwakeup(fpipe);
 					PIPE_UNLOCK(fpipe);
 					fifo_cleanup(vp);
 				}
@@ -238,6 +243,7 @@
 					if (fpipe->pipe_state & PIPE_WANTR)
 						wakeup(fpipe);
 					fpipe->pipe_wgen++;
+					pipeselwakeup(fpipe);
 					PIPE_UNLOCK(fpipe);
 					fifo_cleanup(vp);
 				}
Index: sys/kern/sys_pipe.c
===================================================================
--- sys/kern/sys_pipe.c
+++ sys/kern/sys_pipe.c
@@ -824,7 +824,13 @@
 		}
 	}
 
-	if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF)
+	/*
+	 * Only wake up writers if there was actually something read.
+	 * Otherwise, when calling read(2) at EOF, a spurious wakeup occurs
+	 * that might lead to issues like PR 203366.
+	 */
+	if (nread > 0 &&
+	    (rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF)
 		pipeselwakeup(rpipe);
 
 	PIPE_UNLOCK(rpipe);
@@ -1430,7 +1436,8 @@
 
 	if ((events & POLLINIGNEOF) == 0) {
 		if (rpipe->pipe_state & PIPE_EOF) {
-			revents |= (events & (POLLIN | POLLRDNORM));
+			if (fp->f_flag & FREAD)
+				revents |= (events & (POLLIN | POLLRDNORM));
 			if (wpipe->pipe_present != PIPE_ACTIVE ||
 			    (wpipe->pipe_state & PIPE_EOF))
 				revents |= POLLHUP;
@@ -1605,8 +1612,6 @@
 	pipelock(cpipe, 0);
 	pp = cpipe->pipe_pair;
 
-	pipeselwakeup(cpipe);
-
 	/*
 	 * If the other side is blocked, wake it up saying that
 	 * we want to close it down.
@@ -1620,16 +1625,16 @@
 		pipelock(cpipe, 0);
 	}
 
+	pipeselwakeup(cpipe);
+
 	/*
 	 * Disconnect from peer, if any.
 	 */
 	ppipe = cpipe->pipe_peer;
 	if (ppipe->pipe_present == PIPE_ACTIVE) {
-		pipeselwakeup(ppipe);
-
 		ppipe->pipe_state |= PIPE_EOF;
 		wakeup(ppipe);
-		KNOTE_LOCKED(&ppipe->pipe_sel.si_note, 0);
+		pipeselwakeup(ppipe);
 	}
 
 	/*
@@ -1727,23 +1732,22 @@
 static int
 filt_piperead(struct knote *kn, long hint)
 {
+	struct file *fp = kn->kn_fp;
 	struct pipe *rpipe = kn->kn_hook;
-	struct pipe *wpipe = rpipe->pipe_peer;
-	int ret;
 
 	PIPE_LOCK_ASSERT(rpipe, MA_OWNED);
 	kn->kn_data = rpipe->pipe_buffer.cnt;
 	if (kn->kn_data == 0)
 		kn->kn_data = rpipe->pipe_map.cnt;
 
-	if ((rpipe->pipe_state & PIPE_EOF) ||
-	    wpipe->pipe_present != PIPE_ACTIVE ||
-	    (wpipe->pipe_state & PIPE_EOF)) {
+	if ((rpipe->pipe_state & PIPE_EOF) &&
+	    !((rpipe->pipe_state & PIPE_NAMED) &&
+	        (fp->f_seqcount == rpipe->pipe_wgen))) {
 		kn->kn_flags |= EV_EOF;
 		return (1);
 	}
-	ret = kn->kn_data > 0;
-	return ret;
+	kn->kn_flags &= ~EV_EOF;
+	return (kn->kn_data > 0);
 }
 
 /*ARGSUSED*/
@@ -1757,18 +1761,25 @@
 	 * knlist and the list lock (i.e., the pipe lock) is therefore not held.
 	 */
 	wpipe = kn->kn_hook;
+
+	if (wpipe->pipe_present == PIPE_ACTIVE) {
+		PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
+	}
+
+	if (wpipe->pipe_state & PIPE_DIRECTW) {
+		kn->kn_data = 0;
+	} else if (wpipe->pipe_buffer.size > 0) {
+		kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
+	} else {
+		kn->kn_data = PIPE_BUF;
+	}
+
 	if (wpipe->pipe_present != PIPE_ACTIVE ||
 	    (wpipe->pipe_state & PIPE_EOF)) {
-		kn->kn_data = 0;
 		kn->kn_flags |= EV_EOF;
 		return (1);
 	}
-	PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
-	kn->kn_data = (wpipe->pipe_buffer.size > 0) ?
-	    (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF;
-	if (wpipe->pipe_state & PIPE_DIRECTW)
-		kn->kn_data = 0;
-
+	kn->kn_flags &= ~EV_EOF;
 	return (kn->kn_data >= PIPE_BUF);
 }