diff options
| author | Richard Genoud <richard.genoud@gmail.com> | 2017-03-20 13:52:41 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-31 18:26:19 +0300 |
| commit | 31ca2c63fdc0aee725cbd4f207c1256f5deaabde (patch) | |
| tree | 56d7a7b2697c1c90a988dffb36539f452006763c /drivers/tty | |
| parent | a6040bc610554c66088fda3608ae5d6307c548e4 (diff) | |
| download | linux-31ca2c63fdc0aee725cbd4f207c1256f5deaabde.tar.xz | |
tty/serial: atmel: fix race condition (TX+DMA)
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>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org> # 3.12+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -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 dcebb28ffbc4..5f644515ed33 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1951,6 +1951,11 @@ 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; } /* |