diff options
| author | Richard Genoud <richard.genoud@gmail.com> | 2017-03-20 11:52:41 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2017-04-11 08:04:41 +0200 |
| commit | 238b48d2187884a2852c7c8fe3ac9b5f86a86e4c (patch) | |
| tree | 0fb711290028f12710ed50bd0e1922949cb601cc | |
| parent | f60473f8f623c42b917241f152e9fa248aa0261d (diff) | |
tty/serial: atmel: fix race condition (TX+DMA)
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@microchip.com>
[rg] backport to 3.12
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/tty/serial/atmel_serial.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index ab2e22bf54fd..04a809284d63 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1690,6 +1690,11 @@ 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; } /* |