From: Andrew Liu Date: Tue, 29 Apr 2008 07:36:25 +0000 (+1000) Subject: Fix a potential issue in mpc52xx uart driver X-Git-Tag: v2.6.26-rc1~7^2~7 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fbe543b412cef02350fab35526a6d4dc3d20d182;p=linux-2.6 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 --- diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c index 7a3625f52a..efc971d964 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); }