From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
[ Upstream commit b9491b2e45d71eb64245560e208897af95ffbf95 ]
Accessing LSR requires port lock because it mutates lsr_saved_flags in serial_lsr_in().
Fixes: 197eb5c416ff ("serial: 8250_dw: Use serial_lsr_in() in dw8250_handle_irq()") Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/c5879db7-bee9-93f-526e-872a292442@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_dw.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index c0ab67033a25..d0dfbf1fc9d8 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -266,7 +266,10 @@ static int dw8250_handle_irq(struct uart_port *p)
/* Manually stop the Rx DMA transfer when acting as flow controller */ if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) { + spin_lock_irqsave(&p->lock, flags); status = serial_lsr_in(up); + spin_unlock_irqrestore(&p->lock, flags); + if (status & (UART_LSR_DR | UART_LSR_BI)) { dw8250_writel_ext(p, RZN1_UART_RDMACR, 0); dw8250_writel_ext(p, DW_UART_DMASA, 1);