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> Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.12+ --- NB: this will apply on kernels 4.3+, for kernels before 4.3, the code will be: sg_dma_len(&atmel_port->sg_tx) = 0; 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 d9c05e05d896..5c23fb4e552b 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1954,6 +1954,11 @@ static void atmel_flush_buffer(struct uart_port *port) atmel_uart_writel(port, ATMEL_PDC_TCR, 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; } /* -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
