Commit 3eadc2dc authored by Richard Genoud's avatar Richard Genoud Committed by Greg Kroah-Hartman

tty/serial: atmel: fix race condition (TX+DMA)

commit 31ca2c63 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: default avatarNicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: default avatarRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4f6116cf
......@@ -1938,6 +1938,11 @@ 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;
}
/*
......
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