From 0d7a239ec4d17be3402c4deba0178e1d8f7f21a7 Mon Sep 17 00:00:00 2001
From: visa <visa@openbsd.org>
Date: Mon, 9 May 2022 14:49:55 +0000
Subject: [PATCH] Revert "Replace selwakeup() with KNOTE() in pipe and socket
 event activation."

The commit caused hangs with NFS.

Reported by ajacoutot@ and naddy@
---
 sys/kern/sys_pipe.c     | 9 +++++++--
 sys/kern/uipc_socket.c  | 4 ++--
 sys/kern/uipc_socket2.c | 4 ++--
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index daa6b2ad1c4..ada1e55c7ef 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_pipe.c,v 1.137 2022/05/06 13:09:41 visa Exp $	*/
+/*	$OpenBSD: sys_pipe.c,v 1.138 2022/05/09 14:49:55 visa Exp $	*/
 
 /*
  * Copyright (c) 1996 John S. Dyson
@@ -374,7 +374,12 @@ pipeselwakeup(struct pipe *cpipe)
 {
 	rw_assert_wrlock(cpipe->pipe_lock);
 
-	KNOTE(&cpipe->pipe_sel.si_note, 0);
+	if (cpipe->pipe_state & PIPE_SEL) {
+		cpipe->pipe_state &= ~PIPE_SEL;
+		selwakeup(&cpipe->pipe_sel);
+	} else {
+		KNOTE(&cpipe->pipe_sel.si_note, 0);
+	}
 
 	if (cpipe->pipe_state & PIPE_ASYNC)
 		pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index fc485fdad54..caff3c17100 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket.c,v 1.276 2022/05/06 13:09:41 visa Exp $	*/
+/*	$OpenBSD: uipc_socket.c,v 1.277 2022/05/09 14:49:55 visa Exp $	*/
 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
 
 /*
@@ -2039,7 +2039,7 @@ void
 sohasoutofband(struct socket *so)
 {
 	pgsigio(&so->so_sigio, SIGURG, 0);
-	KNOTE(&so->so_rcv.sb_sel.si_note, 0);
+	selwakeup(&so->so_rcv.sb_sel);
 }
 
 int
diff --git a/sys/kern/uipc_socket2.c b/sys/kern/uipc_socket2.c
index 550779809b0..135bad945e9 100644
--- a/sys/kern/uipc_socket2.c
+++ b/sys/kern/uipc_socket2.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket2.c,v 1.121 2022/05/06 13:09:41 visa Exp $	*/
+/*	$OpenBSD: uipc_socket2.c,v 1.122 2022/05/09 14:49:55 visa Exp $	*/
 /*	$NetBSD: uipc_socket2.c,v 1.11 1996/02/04 02:17:55 christos Exp $	*/
 
 /*
@@ -423,7 +423,7 @@ sowakeup(struct socket *so, struct sockbuf *sb)
 	}
 	if (sb->sb_flags & SB_ASYNC)
 		pgsigio(&so->so_sigio, SIGIO, 0);
-	KNOTE(&sb->sb_sel.si_note, 0);
+	selwakeup(&sb->sb_sel);
 }
 
 /*
-- 
2.20.1