From: Sherry Sun sherry.sun@nxp.com
stable inclusion from linux-4.19.198 commit 4d8421902085c0c373146417088f5ee6a15ad70a
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[ Upstream commit fcb10ee27fb91b25b68d7745db9817ecea9f1038 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/tty/serial/fsl_lpuart.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 4b9f422694779..deb9d4fa9cb09 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1992,6 +1992,9 @@ 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 = clk_get_rate(sport->clk); /*