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From: Ed Maste <emaste@FreeBSD.org>
Date: Tue, 26 Jul 2016 15:34:26 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r303338 - head/sys/dev/vt
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Author: emaste
Date: Tue Jul 26 15:34:26 2016
New Revision: 303338
URL: https://svnweb.freebsd.org/changeset/base/303338

Log:
  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
  MFC after:	3 days

Modified:
  head/sys/dev/vt/vt_core.c

Modified: head/sys/dev/vt/vt_core.c
==============================================================================
--- head/sys/dev/vt/vt_core.c	Tue Jul 26 15:22:21 2016	(r303337)
+++ head/sys/dev/vt/vt_core.c	Tue Jul 26 15:34:26 2016	(r303338)
@@ -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;