From b1d3d2ffcf8855c8ee0bf25d70fa5484d403ac5b Mon Sep 17 00:00:00 2001
From: Bruce Evans <bde@FreeBSD.org>
Date: Wed, 1 May 1996 03:58:21 +0000
Subject: [PATCH] Fixed a race that caused panics in kernel printfs when the
 screen timeout routine changed the screen pointers while output was in
 progress.

---
 sys/dev/syscons/syscons.c | 7 +++++--
 sys/i386/isa/syscons.c    | 7 +++++--
 sys/isa/syscons.c         | 7 +++++--
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/sys/dev/syscons/syscons.c b/sys/dev/syscons/syscons.c
index 9947f75e4ea3..962aa9a9cb96 100644
--- a/sys/dev/syscons/syscons.c
+++ b/sys/dev/syscons/syscons.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: syscons.c,v 1.144 1996/03/27 19:11:41 bde Exp $
+ *  $Id: syscons.c,v 1.145 1996/04/26 06:45:41 sos Exp $
  */
 
 #include "sc.h"
@@ -1215,6 +1215,7 @@ void
 sccnputc(dev_t dev, int c)
 {
     u_char buf[1];
+    int s;
     scr_stat *scp = console[0];
     term_stat save = scp->term;
 
@@ -1227,7 +1228,8 @@ sccnputc(dev_t dev, int c)
     kernel_console = scp->term;
     current_default = &user_default;
     scp->term = save;
-    if (scp == cur_console /* && scrn_timer not running */) {
+    s = splclock();		/* XXX stop scrn_timer */
+    if (scp == cur_console) {
 	if (scp->scr_buf != Crtat && (scp->start <= scp->end)) {
 	    bcopyw(scp->scr_buf + scp->start, Crtat + scp->start,
 		   (1 + scp->end - scp->start) * sizeof(u_short));
@@ -1237,6 +1239,7 @@ sccnputc(dev_t dev, int c)
 	}
 	draw_cursor(scp, TRUE);
     }
+    splx(s);
 }
 
 int
diff --git a/sys/i386/isa/syscons.c b/sys/i386/isa/syscons.c
index 9947f75e4ea3..962aa9a9cb96 100644
--- a/sys/i386/isa/syscons.c
+++ b/sys/i386/isa/syscons.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: syscons.c,v 1.144 1996/03/27 19:11:41 bde Exp $
+ *  $Id: syscons.c,v 1.145 1996/04/26 06:45:41 sos Exp $
  */
 
 #include "sc.h"
@@ -1215,6 +1215,7 @@ void
 sccnputc(dev_t dev, int c)
 {
     u_char buf[1];
+    int s;
     scr_stat *scp = console[0];
     term_stat save = scp->term;
 
@@ -1227,7 +1228,8 @@ sccnputc(dev_t dev, int c)
     kernel_console = scp->term;
     current_default = &user_default;
     scp->term = save;
-    if (scp == cur_console /* && scrn_timer not running */) {
+    s = splclock();		/* XXX stop scrn_timer */
+    if (scp == cur_console) {
 	if (scp->scr_buf != Crtat && (scp->start <= scp->end)) {
 	    bcopyw(scp->scr_buf + scp->start, Crtat + scp->start,
 		   (1 + scp->end - scp->start) * sizeof(u_short));
@@ -1237,6 +1239,7 @@ sccnputc(dev_t dev, int c)
 	}
 	draw_cursor(scp, TRUE);
     }
+    splx(s);
 }
 
 int
diff --git a/sys/isa/syscons.c b/sys/isa/syscons.c
index 9947f75e4ea3..962aa9a9cb96 100644
--- a/sys/isa/syscons.c
+++ b/sys/isa/syscons.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: syscons.c,v 1.144 1996/03/27 19:11:41 bde Exp $
+ *  $Id: syscons.c,v 1.145 1996/04/26 06:45:41 sos Exp $
  */
 
 #include "sc.h"
@@ -1215,6 +1215,7 @@ void
 sccnputc(dev_t dev, int c)
 {
     u_char buf[1];
+    int s;
     scr_stat *scp = console[0];
     term_stat save = scp->term;
 
@@ -1227,7 +1228,8 @@ sccnputc(dev_t dev, int c)
     kernel_console = scp->term;
     current_default = &user_default;
     scp->term = save;
-    if (scp == cur_console /* && scrn_timer not running */) {
+    s = splclock();		/* XXX stop scrn_timer */
+    if (scp == cur_console) {
 	if (scp->scr_buf != Crtat && (scp->start <= scp->end)) {
 	    bcopyw(scp->scr_buf + scp->start, Crtat + scp->start,
 		   (1 + scp->end - scp->start) * sizeof(u_short));
@@ -1237,6 +1239,7 @@ sccnputc(dev_t dev, int c)
 	}
 	draw_cursor(scp, TRUE);
     }
+    splx(s);
 }
 
 int