svn commit: r303632 - stable/11/sys/dev/vt

[Ed Maste]

Author: emaste
Date: Mon Aug  1 19:50:28 2016
New Revision: 303632
URL: https://svnweb.freebsd.org/changeset/base/303632

Log:
  MFC r303338:   vt: lock Giant around kbd calls in CONS_GETINFO
  
  Note that keyboards are stored in an array and are not freed (just
  "unregistered" by clearing some fields) so a race would be limited to
  obtaining stale information about an unregistered keyboard.
  
  Reported by:	CTurt
  Approved by:	re (gjb, kib)

Modified:
  stable/11/sys/dev/vt/vt_core.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/vt/vt_core.c
==============================================================================
--- stable/11/sys/dev/vt/vt_core.c	Mon Aug  1 19:49:42 2016	(r303631)
+++ stable/11/sys/dev/vt/vt_core.c	Mon Aug  1 19:50:28 2016	(r303632)
@@ -2228,9 +2228,11 @@ skip_thunk:
 			return (EINVAL);
 
 		if (vw == vd->vd_curwindow) {
+			mtx_lock(&Giant);
 			kbd = kbd_get_keyboard(vd->vd_keyboard);
 			if (kbd != NULL)
 				vt_save_kbd_state(vw, kbd);
+			mtx_unlock(&Giant);
 		}
 
 		vi->m_num = vd->vd_curwindow->vw_number + 1;