From fbe543b412cef02350fab35526a6d4dc3d20d182 Mon Sep 17 00:00:00 2001 From: Andrew Liu Date: Tue, 29 Apr 2008 17:36:25 +1000 Subject: [PATCH] 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 Signed-off-by: Grant Likely --- drivers/serial/mpc52xx_uart.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c index 7a3625f52a03..efc971d9647b 100644 --- a/drivers/serial/mpc52xx_uart.c +++ b/drivers/serial/mpc52xx_uart.c @@ -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); }