tree 0fb711290028f12710ed50bd0e1922949cb601cc
parent f60473f8f623c42b917241f152e9fa248aa0261d
author Richard Genoud <richard.genoud@gmail.com> 1490007161 +0100
committer Jiri Slaby <jslaby@suse.cz> 1491890681 +0200

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>