[PATCH 4.19 078/134] tty: mxs-auart: fix a potential NULL pointer dereference

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kangjie Lu <k...@umn.edu>

commit 6734330654dac550f12e932996b868c6d0dcb421 upstream.

In case ioremap fails, the fix returns -ENOMEM to avoid NULL
pointer dereferences.
Multiple places use port.membase.

Signed-off-by: Kangjie Lu <k...@umn.edu>
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/tty/serial/mxs-auart.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1685,6 +1685,10 @@ static int mxs_auart_probe(struct platfo
 
        s->port.mapbase = r->start;
        s->port.membase = ioremap(r->start, resource_size(r));
+       if (!s->port.membase) {
+               ret = -ENOMEM;
+               goto out_disable_clks;
+       }
        s->port.ops = &mxs_auart_ops;
        s->port.iotype = UPIO_MEM;
        s->port.fifosize = MXS_AUART_FIFO_SIZE;