diff --git a/debug-tty-print-dev-name.patch b/debug-tty-print-dev-name.patch
new file mode 100644
index 000000000..9010b64fa
--- /dev/null
+++ b/debug-tty-print-dev-name.patch
@@ -0,0 +1,17 @@
+diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
+index 613c852..09c86d2 100644
+--- a/drivers/tty/tty_io.c
++++ b/drivers/tty/tty_io.c
+@@ -1322,7 +1322,11 @@ static int tty_reopen(struct tty_struct *tty)
+ 	tty->driver = driver; /* N.B. why do this every time?? */
+ 
+ 	mutex_lock(&tty->ldisc_mutex);
+-	WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
++	if (!test_bit(TTY_LDISC, &tty->flags)) {
++		printk("%s: !test_bit(TTY_LDISC, &tty->flags) dev=%s ldisc=%s\n",
++			__func__, tty->name, tty->ldisc ? tty->ldisc->ops ? tty->ldisc->ops->name : NULL : NULL);
++		WARN_ON(1);
++	}
+ 	mutex_unlock(&tty->ldisc_mutex);
+ 
+ 	return 0;
diff --git a/kernel.spec b/kernel.spec
index 9df0131bc..752361548 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -700,6 +700,7 @@ Patch12205: runtime_pm_fixups.patch
 Patch12303: dmar-disable-when-ricoh-multifunction.patch
 
 Patch12400: tty-dont-allow-reopen-when-ldisc-is-changing.patch
+Patch12401: debug-tty-print-dev-name.patch
 
 %endif
 
@@ -1291,6 +1292,7 @@ ApplyPatch dmar-disable-when-ricoh-multifunction.patch
 
 # rhbz#630464
 ApplyPatch tty-dont-allow-reopen-when-ldisc-is-changing.patch
+ApplyPatch debug-tty-print-dev-name.patch
 
 # END OF PATCH APPLICATIONS
 
@@ -1904,6 +1906,9 @@ fi
 #                 ||     ||
 
 %changelog
+* Fri Nov 26 2010 Kyle McMartin <kyle@redhat.com>
+- Copy tty_open WARN_ON debugging patch from rawhide.
+
 * Fri Nov 26 2010 Kyle McMartin <kyle@redhat.com> 2.6.37-0.rc3.git2.1
 - Linux 2.6.37-rc3-git2
 - CGROUP_MEM_RES_CTLR_SWAP_ENABLED is not set, so the cgroup memory