Commit fbe543b4 authored Apr 29, 2008 by Andrew Liu Committed by Grant Likely May 01, 2008

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>

parent 80791be1

drivers/serial/mpc52xx_uart.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -783,7 +783,9 @@ mpc52xx_uart_int_rx_chars(struct uart_port *port)
		}
		}

		spin_unlock(&port->lock);
		tty_flip_buffer_push(tty);
		spin_lock(&port->lock);

		return psc_ops->raw_rx_rdy(port);
		}