[Midnightbsd-cvs] src [11931] trunk/sys/kern/subr_terminal.c: Fix a panic during boot caused by inadequate locking of some vt(4) driver

[laffer1 at midnightbsd.org]

Revision: 11931
          http://svnweb.midnightbsd.org/src/?rev=11931
Author:   laffer1
Date:     2018-07-21 09:30:22 -0400 (Sat, 21 Jul 2018)
Log Message:
-----------
Fix a panic during boot caused by inadequate locking of some vt(4) driver
  data structures.

  vt_change_font() calls vtbuf_grow() to change some vt driver data
  structures. It uses TF_MUTE to prevent the console from trying to use
  those data structures while it changes them.

  During the early stage of the boot process, the vt driver's tc_done
  routine uses those data structures; however, it is currently called
  outside the TF_MUTE check.

  Move the tc_done routine inside the locked TF_MUTE check.

Obtained from: FreeBSD svn 332831

Modified Paths:
--------------
    trunk/sys/kern/subr_terminal.c

Modified: trunk/sys/kern/subr_terminal.c
===================================================================
--- trunk/sys/kern/subr_terminal.c	2018-07-20 22:42:34 UTC (rev 11930)
+++ trunk/sys/kern/subr_terminal.c	2018-07-21 13:30:22 UTC (rev 11931)
@@ -376,7 +376,10 @@
 		TERMINAL_UNLOCK_TTY(tm);
 	}
 
-	tm->tm_class->tc_done(tm);
+	TERMINAL_LOCK_TTY(tm);
+	if (!(tm->tm_flags & TF_MUTE))
+		tm->tm_class->tc_done(tm);
+	TERMINAL_UNLOCK_TTY(tm);
 	if (flags & TF_BELL)
 		tm->tm_class->tc_bell(tm);
 }
@@ -546,10 +549,9 @@
 		teken_set_curattr(&tm->tm_emulator, &kernel_message);
 		teken_input(&tm->tm_emulator, &cv, 1);
 		teken_set_curattr(&tm->tm_emulator, &backup);
+		tm->tm_class->tc_done(tm);
 	}
 	TERMINAL_UNLOCK_CONS(tm);
-
-	tm->tm_class->tc_done(tm);
 }
 
 /*