[PATCH 3.16 025/157] tty: mxs-auart: fix a potential NULL pointer dereference

[Ben Hutchings]

3.16.72-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Kangjie Lu <kjlu@xxxxxxx>

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 <kjlu@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: There is no out_disable_clks label, so goto
 out_free_clk on error]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 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
@@ -1075,6 +1075,10 @@ 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_free_clk;
+	}
 	s->port.ops = &mxs_auart_ops;
 	s->port.iotype = UPIO_MEM;
 	s->port.fifosize = MXS_AUART_FIFO_SIZE;