From 866746b6a6c6b56dfe50027fde9b2dfecbdef8a6 Mon Sep 17 00:00:00 2001
From: David Greenman <dg@FreeBSD.org>
Date: Sun, 12 Nov 2000 14:51:15 +0000
Subject: [PATCH] Fixed a certain panic on IO error in sendfile(): Page must be
 set PG_BUSY before calling vm_page_free() on it.

---
 sys/kern/uipc_syscalls.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 83ddc355e93..ae7b7e9e4d3 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -1599,8 +1599,10 @@ retry_lookup:
 				 */
 				if (pg->wire_count == 0 && pg->valid == 0 &&
 				    pg->busy == 0 && !(pg->flags & PG_BUSY) &&
-				    pg->hold_count == 0)
+				    pg->hold_count == 0) {
+					vm_page_busy(pg);
 					vm_page_free(pg);
+				}
 				sbunlock(&so->so_snd);
 				goto done;
 			}