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authorRichard Genoud <richard.genoud@gmail.com>2017-03-20 11:52:41 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-31 17:26:19 +0200
commit31ca2c63fdc0aee725cbd4f207c1256f5deaabde (patch)
tree56d7a7b2697c1c90a988dffb36539f452006763c /drivers/tty
parenta6040bc610554c66088fda3608ae5d6307c548e4 (diff)
downloadlinux-31ca2c63fdc0aee725cbd4f207c1256f5deaabde.tar.bz2
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.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 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;
}
/*