Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f8fd1b03 authored by Loic Poulain's avatar Loic Poulain Committed by Greg Kroah-Hartman
Browse files

serial: 8250: Fix thread unsafe __dma_tx_complete function 



__dma_tx_complete is not protected against concurrent
call of serial8250_tx_dma. it can lead to circular tail
index corruption or parallel call of serial_tx_dma on the
same data portion.

This patch fixes this issue by holding the port lock.

Signed-off-by: default avatarLoic Poulain <loic.poulain@intel.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b08c9c31

drivers/tty/serial/8250/8250_dma.c

+7 −2
Original line number Diff line number Diff line
@@ -20,12 +20,15 @@ static void __dma_tx_complete(void *param) 
	struct uart_8250_port	*p = param;

	struct uart_8250_dma	*dma = p->dma;

	struct circ_buf		*xmit = &p->port.state->xmit;



	dma->tx_running = 0;

	unsigned long	flags;



	dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,

				UART_XMIT_SIZE, DMA_TO_DEVICE);



	spin_lock_irqsave(&p->port.lock, flags);



	dma->tx_running = 0;



	xmit->tail += dma->tx_size;

	xmit->tail &= UART_XMIT_SIZE - 1;

	p->port.icount.tx += dma->tx_size;
@@ -35,6 +38,8 @@ static void __dma_tx_complete(void *param) 


	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port))

		serial8250_tx_dma(p);



	spin_unlock_irqrestore(&p->port.lock, flags);

}



static void __dma_rx_complete(void *param)