tty: serial: fsl_lpuart: fix the potential risk of division or modulo by zero

We should be very careful about the register values that will be used
for division or modulo operations, althrough the possibility that the
UARTBAUD register value is zero is very low, but we had better to deal
with the "bad data" of hardware in advance to avoid division or modulo
by zero leading to undefined kernel behavior.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210427021226.27468-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sherry Sun 2021-04-27 10:12:26 +08:00 committed by Greg Kroah-Hartman
parent 52008ebd62
commit fcb10ee27f
1 changed files with 3 additions and 0 deletions

View File

@ -2414,6 +2414,9 @@ lpuart32_console_get_options(struct lpuart_port *sport, int *baud,
bd = lpuart32_read(&sport->port, UARTBAUD);
bd &= UARTBAUD_SBR_MASK;
if (!bd)
return;
sbr = bd;
uartclk = lpuart_get_baud_clk_rate(sport);
/*