[PATCH v4 5/5] serial/8250: Only use fifo after the port is initialized in console_write

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The serial driver set the value of uart_8250_port.fcr in the function
serial8250_config_port, but only writes the value to the controller
register later in the initalization code.

That opens a small window in which is not safe to use the fifo for
console write.

Make sure the port is initialized correctly before reading the FCR
cached value.

Unfortunately, I lost track of who originally reported the issue. If
s/he is reading this, please speak up so I can give you the due credit.

Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_port.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 4acf620be241..7e2227161555 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3416,6 +3416,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 		!(up->capabilities & UART_CAP_MINI) &&
 		up->tx_loadsz > 1 &&
 		(up->fcr & UART_FCR_ENABLE_FIFO) &&
+		test_bit(TTY_PORT_INITIALIZED, &port->state->port.iflags) &&
 		/*
 		 * After we put a data in the fifo, the controller will send
 		 * it regardless of the CTS state. Therefore, only use fifo
-- 
2.35.1




[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux