[PATCH 3.13 056/140] tty/serial: at91: fix race condition in atmel_serial_remove

Greg Kroah-Hartman
2014-02-04T21:40:42Z

From: Marek Roszko <mark.roszko@gmail.com>

commit f50c995f9ebf064cea1368bf361c4e29679415b4 upstream.

The _remove callback could be called when a tasklet is scheduled. tasklet_kill
was called inside the function in order to free up any scheduled tasklets.
However it was called after uart_remove_one_port which destroys tty references
needed in the port for atmel_tasklet_func.
Simply putting the tasklet_kill at the start of the function will prevent this
conflict.

Signed-off-by: Marek Roszko <mark.roszko@gmail.com>
Acked-by: Leilei Zhao <leilei.zhao@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/tty/serial/atmel_serial.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2447,11 +2447,12 @@ static int atmel_serial_remove(struct pl
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
int ret = 0;

+ tasklet_kill(&atmel_port->tasklet);
+
device_init_wakeup(&pdev->dev, 0);

ret = uart_remove_one_port(&atmel_uart, port);

- tasklet_kill(&atmel_port->tasklet);
kfree(atmel_port->rx_ring.buf);

/* "port" is allocated statically, so we shouldn't free it */