| Message ID | 20221129141819.15310-1-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | USB: serial: f81534: fix division by zero on line-speed change | expand |
On Tue, Nov 29, 2022 at 03:18:19PM +0100, Johan Hovold wrote: > The driver leaves the line speed unchanged in case a requested speed is > not supported. Make sure to handle the case where the current speed is > B0 (hangup) without dividing by zero when determining the clock source. > > Fixes: 3aacac02f385 ("USB: serial: f81534: add high baud rate support") > Cc: stable@vger.kernel.org # 4.16 > Cc: Ji-Ze Hong (Peter Hong) <hpeter@gmail.com> > Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c index ddfcd72eb0ae..4083ae961be4 100644 --- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -536,9 +536,6 @@ static int f81534_submit_writer(struct usb_serial_port *port, gfp_t mem_flags) static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate) { - if (!baudrate) - return 0; - /* Round to nearest divisor */ return DIV_ROUND_CLOSEST(clockrate, baudrate); } @@ -568,9 +565,14 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baud_list[] = {baudrate, old_baudrate, F81534_DEFAULT_BAUD_RATE}; for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81534_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return 0; + } + + idx = f81534_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }
The driver leaves the line speed unchanged in case a requested speed is not supported. Make sure to handle the case where the current speed is B0 (hangup) without dividing by zero when determining the clock source. Fixes: 3aacac02f385 ("USB: serial: f81534: add high baud rate support") Cc: stable@vger.kernel.org # 4.16 Cc: Ji-Ze Hong (Peter Hong) <hpeter@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/f81534.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)