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| author | Richard Genoud <richard.genoud@gmail.com> | 2017-03-20 11:52:41 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-08 09:53:31 +0200 |
| commit | 74b8fc017d7689d1a60c9e234b2cfe3550b7f414 (patch) | |
| tree | a8bdb94a910d3599e7208fb710a9a9ecc31b0e21 /drivers | |
| parent | 566a8711a7dd11960fa0bf3a4fd89c742eb359f3 (diff) | |
| download | linux-stable-74b8fc017d7689d1a60c9e234b2cfe3550b7f414.tar.gz linux-stable-74b8fc017d7689d1a60c9e234b2cfe3550b7f414.tar.bz2 linux-stable-74b8fc017d7689d1a60c9e234b2cfe3550b7f414.zip | |
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>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -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 a0f911641b04..156a262b6b65 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1987,6 +1987,11 @@ 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; } /* |