2020-07-21 17:15:52

by B K Karthik

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Subject: [PATCH 1/2] tty: serial: fsl_lpuart.c: prevent a bad shift operation

---

prevent a bad shift operation by verifying that
sport->rx_dma_rng_buf_len is non zero.

Signed-off-by: B K Karthik <[email protected]>
---
drivers/tty/serial/fsl_lpuart.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 7ca642249224..0cc64279cd2d 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1168,7 +1168,8 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
* 10ms at any baud rate.
*/
sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / bits / 1000) * 2;
- sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
+ if (sport->rx_dma_rng_buf_len != 0)
+ sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
if (sport->rx_dma_rng_buf_len < 16)
sport->rx_dma_rng_buf_len = 16;

--
2.20.1

---

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2020-07-21 17:35:37

by Greg Kroah-Hartman

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Subject: Re: [PATCH 1/2] tty: serial: fsl_lpuart.c: prevent a bad shift operation

---

On Tue, Jul 21, 2020 at 10:43:11PM +0530, B K Karthik wrote:
> prevent a bad shift operation by verifying that
> sport->rx_dma_rng_buf_len is non zero.
>
> Signed-off-by: B K Karthik <[email protected]>
> ---
> drivers/tty/serial/fsl_lpuart.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

What about setting the "Reported-by:" to the person who reported this
problem? And cc:ing them to see if they agree with your change?

thanks,

greg k-h