commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 97a64bc79350..b47335dfae16 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1824,10 +1824,9 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) if (!up->dma->rx_running) break; fallthrough; + case UART_IIR_RLSI: case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up); - /* fall-through */ - case UART_IIR_RLSI: return true; } return up->dma->rx_dma(up);
On Mon, Nov 21, 2022 at 02:49:25PM +0200, Ilpo Järvinen wrote:
commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
Applied to 5.4.y only. Fails to apply to 4.9.y, 4.14.y, or 4.19.y :(
commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index cab3a74281ef..8aee43fe488a 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1802,10 +1802,9 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) if (!up->dma->rx_running) break; /* fall-through */ + case UART_IIR_RLSI: case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up); - /* fall-through */ - case UART_IIR_RLSI: return true; } return up->dma->rx_dma(up);
On Tue, Nov 22, 2022 at 03:14:10PM +0200, Ilpo Järvinen wrote:
commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index cab3a74281ef..8aee43fe488a 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1802,10 +1802,9 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) if (!up->dma->rx_running) break; /* fall-through */
- case UART_IIR_RLSI: case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up);
/* fall-through */- case UART_IIR_RLSI: return true; } return up->dma->rx_dma(up);
-- 2.30.2
Now queued up, thanks.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg Kroah-Hartman -
Ilpo Järvinen