1 files changed, 28 insertions, 11 deletions

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index e46d628998f5..81f23af8beca 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -89,6 +89,8 @@ static LIST_HEAD(hvc_structs);
  */
 static DEFINE_SPINLOCK(hvc_structs_lock);
 
+/* Mutex to serialize hvc_open */
+static DEFINE_MUTEX(hvc_open_mutex);
 /*
  * This value is used to assign a tty->index value to a hvc_struct based
  * upon order of exposure via hvc_probe(), when we can not match it to
@@ -289,10 +291,6 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
 	vtermnos[index] = vtermno;
 	cons_ops[index] = ops;
 
-	/* reserve all indices up to and including this index */
-	if (last_hvc < index)
-		last_hvc = index;
-
 	/* check if we need to re-register the kernel console */
 	hvc_check_console(index);
 
@@ -337,16 +335,24 @@ static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
  */
 static int hvc_open(struct tty_struct *tty, struct file * filp)
 {
-	struct hvc_struct *hp = tty->driver_data;
+	struct hvc_struct *hp;
 	unsigned long flags;
 	int rc = 0;
 
+	mutex_lock(&hvc_open_mutex);
+
+	hp = tty->driver_data;
+	if (!hp) {
+		rc = -EIO;
+		goto out;
+	}
+
 	spin_lock_irqsave(&hp->port.lock, flags);
 	/* Check and then increment for fast path open. */
 	if (hp->port.count++ > 0) {
 		spin_unlock_irqrestore(&hp->port.lock, flags);
 		hvc_kick();
-		return 0;
+		goto out;
 	} /* else count == 0 */
 	spin_unlock_irqrestore(&hp->port.lock, flags);
 
@@ -375,6 +381,8 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 	/* Force wakeup of the polling thread */
 	hvc_kick();
 
+out:
+	mutex_unlock(&hvc_open_mutex);
 	return rc;
 }
 
@@ -896,13 +904,22 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
 		    cons_ops[i] == hp->ops)
 			break;
 
-	/* no matching slot, just use a counter */
-	if (i >= MAX_NR_HVC_CONSOLES)
-		i = ++last_hvc;
+	if (i >= MAX_NR_HVC_CONSOLES) {
+
+		/* find 'empty' slot for console */
+		for (i = 0; i < MAX_NR_HVC_CONSOLES && vtermnos[i] != -1; i++) {
+		}
+
+		/* no matching slot, just use a counter */
+		if (i == MAX_NR_HVC_CONSOLES)
+			i = ++last_hvc + MAX_NR_HVC_CONSOLES;
+	}
 
 	hp->index = i;
-	cons_ops[i] = ops;
-	vtermnos[i] = vtermno;
+	if (i < MAX_NR_HVC_CONSOLES) {
+		cons_ops[i] = ops;
+		vtermnos[i] = vtermno;
+	}
 
 	list_add_tail(&(hp->next), &hvc_structs);
 	spin_unlock(&hvc_structs_lock);