[018/107] drivers/tty/serial/pch_uart.c: dont oops if dmi_get_system_info returns NULL

[Greg KH]

2.6.39-stable review patch.  If anyone has any objections, please let us know.

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

From: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>

commit fb139dfeef9558a12ffdbf9e26951fd1a9304f3b upstream.

If dmi_get_system_info() returns NULL, pch_uart_init_port() will
dereferencea a zero pointer.

This oops was observed on an Atom based board which has no BIOS, but
a bootloder which doesn't provide DMI data.

Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/tty/serial/pch_uart.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1392,6 +1392,7 @@ static struct eg20t_port *pch_uart_init_
 	int fifosize, base_baud;
 	int port_type;
 	struct pch_uart_driver_data *board;
+	const char *board_name;
 
 	board = &drv_dat[id->driver_data];
 	port_type = board->port_type;
@@ -1407,7 +1408,8 @@ static struct eg20t_port *pch_uart_init_
 	base_baud = 1843200; /* 1.8432MHz */
 
 	/* quirk for CM-iTC board */
-	if (strstr(dmi_get_system_info(DMI_BOARD_NAME), "CM-iTC"))
+	board_name = dmi_get_system_info(DMI_BOARD_NAME);
+	if (board_name && strstr(board_name, "CM-iTC"))
 		base_baud = 192000000; /* 192.0MHz */
 
 	switch (port_type) {


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