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authorJi-Ze Hong (Peter Hong) <hpeter@gmail.com>2017-11-08 11:05:46 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-08 13:09:35 +0100
commit07a708f0a16f040b319db647452bcb8884cd04be (patch)
tree2c677e48e42007574c7210fc28e2f8c37d97a54d
parent21c4e7f255e38620bb4c5d1119c64114ab280e2e (diff)
serial: 8250_fintek: Fix crash with baud rate B0
The 8250_fintek.c is support the Fintek F81866/F81216 with dynamic clock. But It'll generate "division by zero" exception and crash in fintek_8250_set_termios() with baud rate 0 on baudrate_table[i] % baud. It can be tested with following C code: ... struct termios options; tcgetattr(fd, &options); ... options.c_cflag = CS8 | CREAD; /* baud rate 0 */ tcsetattr(fd, TCSANOW, &options); tcflush(fd, TCIOFLUSH); Fixes: 195638b6d44f ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81866") Reported-by: Lukas Redlinger <rel+kernel@agilox.net> Cc: Lukas Redlinger <rel+kernel@agilox.net> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/serial/8250/8250_fintek.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index ae7d86e44b76..79a4958b3f5c 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -315,6 +315,13 @@ void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
F81866_UART_CLK_14_769MHZ, F81866_UART_CLK_18_432MHZ,
F81866_UART_CLK_24MHZ };
+ /*
+ * We'll use serial8250_do_set_termios() for baud = 0, otherwise It'll
+ * crash on baudrate_table[i] % baud with "division by zero".
+ */
+ if (!baud)
+ goto exit;
+
switch (pdata->pid) {
case CHIP_ID_F81216H:
reg = RS485;
@@ -327,8 +334,7 @@ void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
dev_warn(port->dev,
"%s: pid: %x Not support. use default set_termios.\n",
__func__, pdata->pid);
- serial8250_do_set_termios(port, termios, old);
- return;
+ goto exit;
}
for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
@@ -356,6 +362,7 @@ void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
tty_termios_encode_baud_rate(termios, baud, baud);
}
+exit:
serial8250_do_set_termios(port, termios, old);
}