From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit 27a826837ec9a3e94cc44bd9328b8289b0fcecd7 upstream. The atmel_complete_tx_dma() function disables IRQs at the start of the function by calling spin_lock_irqsave(&port->lock, flags); There is no need to disable them a second time using the spin_lock_irq() function and, in fact, doing so is a bug because it will enable IRQs prematurely when we call spin_unlock_irq(). Just use spin_lock/unlock() instead without disabling or enabling IRQs. Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Jiri Slaby <jirislaby@xxxxxxxxxx> Acked-by: Richard Genoud <richard.genoud@xxxxxxxxx> Link: https://lore.kernel.org/r/cb7c39a9-c004-4673-92e1-be4e34b85368@moroto.mountain Cc: stable <stable@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/atmel_serial.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -873,11 +873,11 @@ static void atmel_complete_tx_dma(void * port->icount.tx += atmel_port->tx_len; - spin_lock_irq(&atmel_port->lock_tx); + spin_lock(&atmel_port->lock_tx); async_tx_ack(atmel_port->desc_tx); atmel_port->cookie_tx = -EINVAL; atmel_port->desc_tx = NULL; - spin_unlock_irq(&atmel_port->lock_tx); + spin_unlock(&atmel_port->lock_tx); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port);