Fix a potential issue in mpc52xx uart driver
mpc52xx_uart_int and __uart_put_char both try to acquire the
port->lock. Therefore the function sequence of:
mpc52xx_uart_int--> ...-->flush_to_ldisc-->...-->__uart_put_char
can potentially trigger a deadlock. To avoid this deadlock a fix
similar to that found in the 8250.c serial driver is applied. The
deadlock is avoided by releasing the lock before pushing a buffer
and reacquiring it when completed.
Signed-off-by: Andrew Liu <shengping.liu@windriver.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index 7a3625f..efc971d 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -783,7 +783,9 @@
}
}
+ spin_unlock(&port->lock);
tty_flip_buffer_push(tty);
+ spin_lock(&port->lock);
return psc_ops->raw_rx_rdy(port);
}