tty: serial: max3100: Fix error case

We don't want to free a random address if the entry is wrong, cover
this and WARN if it ever happens.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/tty/serial/max3100.c b/drivers/tty/serial/max3100.c
index 46043c2521c..0f24486be53 100644
--- a/drivers/tty/serial/max3100.c
+++ b/drivers/tty/serial/max3100.c
@@ -827,14 +827,16 @@ static int __devexit max3100_remove(struct spi_device *spi)
 
         /* find out the index for the chip we are removing */
         for (i = 0; i < MAX_MAX3100; i++)
-                if (max3100s[i] == s)
+                if (max3100s[i] == s) {
+                        dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
+                        uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
+                        kfree(max3100s[i]);
+                        max3100s[i] = NULL;
                         break;
+                }
 
-        dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
-        uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
-        kfree(max3100s[i]);
-        max3100s[i] = NULL;
-
+        WARN_ON(i == MAX_MAX3100);
+        
         /* check if this is the last chip we have */
         for (i = 0; i < MAX_MAX3100; i++)
                 if (max3100s[i]) {