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authorRichard Genoud <richard.genoud@gmail.com>2017-03-20 11:52:41 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-08 09:53:31 +0200
commit74b8fc017d7689d1a60c9e234b2cfe3550b7f414 (patch)
treea8bdb94a910d3599e7208fb710a9a9ecc31b0e21 /drivers
parent566a8711a7dd11960fa0bf3a4fd89c742eb359f3 (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> 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.c5
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;
}
/*