diff options
| author | Loic Poulain <loic.poulain@intel.com> | 2014-04-24 11:34:48 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-07 10:28:08 -0700 |
| commit | 7d056f1066bd1d677273e3db285e00f0fd80674d (patch) | |
| tree | fab33dd9a9f971f10dc06bf6f633ed0c147271f6 | |
| parent | e83c667a1f451b1ae47a27d5e2ef0acb5f2c5b3d (diff) | |
serial: 8250: Fix thread unsafe __dma_tx_complete function
commit f8fd1b0350d3a4581125f5eda6528f5a2c5f9183 upstream.
__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: Loic Poulain <loic.poulain@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_dma.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 7046769608d..ab9096dc384 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -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) |