On 20/04/2017 08:35, Greg Kroah-Hartman wrote: > 3.18-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Richard Genoud <richard.genoud@xxxxxxxxx> > > commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream. > > If uart_flush_buffer() is called between atmel_tx_dma() and > atmel_complete_tx_dma(), the circular buffer has been cleared, but not > atmel_port->tx_len. > That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE - > atmel_port->tx_len) bytes). > > Tested-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx> > Signed-off-by: Richard Genoud <richard.genoud@xxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > drivers/tty/serial/atmel_serial.c | 5 +++++ > 1 file changed, 5 insertions(+) > > --- a/drivers/tty/serial/atmel_serial.c > +++ b/drivers/tty/serial/atmel_serial.c > @@ -1867,6 +1867,11 @@ static void atmel_flush_buffer(struct ua > UART_PUT_TCR(port, 0); > atmel_port->pdc_tx.ofs = 0; > } > + /* > + * in uart_flush_buffer(), the xmit circular buffer has just > + * been cleared, so we have to reset tx_len accordingly. > + */ > + atmel_port->tx_len = 0; > } > > /* > > Hi, This won't compile on 3.18 kernel since ->tx_len doesn't exist yet. Here is the backported version of this patch: Thanks ! ====================== commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream. If uart_flush_buffer() is called between atmel_tx_dma() and atmel_complete_tx_dma(), the circular buffer has been cleared, but not its length. That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE - sg_dma_len(&atmel_port->sg_tx)) bytes). Signed-off-by: Richard Genoud <richard.genoud@xxxxxxxxx> --- drivers/tty/serial/atmel_serial.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index daaed7c79e4f..a10c778be2ad 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1867,6 +1867,11 @@ static void atmel_flush_buffer(struct uart_port *port) UART_PUT_TCR(port, 0); atmel_port->pdc_tx.ofs = 0; } + /* + * in uart_flush_buffer(), the xmit circular buffer has just + * been cleared, so we have to reset its length accordingly. + */ + sg_dma_len(&atmel_port->sg_tx) = 0; } /*