startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS. The register is also accessed from write() callback.

If console were printing and startup()/shutdown() callback gets called, its access to the register could be overwritten.

Add port->lock to startup()/shutdown() callbacks to make sure their access to SIFIVE_SERIAL_IE_OFFS is synchronized against write() callback.

Signed-off-by: Ryo Takakura ryotkkr98@gmail.com Cc: stable@vger.kernel.org --- drivers/tty/serial/sifive.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c index 5904a2d4c..054a8e630 100644 --- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -563,8 +563,11 @@ static void sifive_serial_break_ctl(struct uart_port *port, int break_state) static int sifive_serial_startup(struct uart_port *port) { struct sifive_serial_port *ssp = port_to_sifive_serial_port(port); + unsigned long flags;

+ uart_port_lock_irqsave(&ssp->port, &flags); __ssp_enable_rxwm(ssp); + uart_port_unlock_irqrestore(&ssp->port, flags);

return 0; } @@ -572,9 +575,12 @@ static int sifive_serial_startup(struct uart_port *port) static void sifive_serial_shutdown(struct uart_port *port) { struct sifive_serial_port *ssp = port_to_sifive_serial_port(port); + unsigned long flags;

+ uart_port_lock_irqsave(&ssp->port, &flags); __ssp_disable_rxwm(ssp); __ssp_disable_txwm(ssp); + uart_port_unlock_irqrestore(&ssp->port, flags); }

/**