Re: [PATCH] rtc: remove VLA usage
From: Alexandre Belloni
Date: Wed Mar 07 2018 - 16:25:23 EST
On 07/03/2018 at 14:11:33 -0600, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wvla, remove VLA and replace it
> with a fixed-length array instead.
>
You should probably explain what VLA is and why this is important to do.
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
> drivers/rtc/rtc-bq32k.c | 2 +-
> drivers/rtc/rtc-mcp795.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rtc/rtc-bq32k.c b/drivers/rtc/rtc-bq32k.c
> index e8698e9..e4b234a 100644
> --- a/drivers/rtc/rtc-bq32k.c
> +++ b/drivers/rtc/rtc-bq32k.c
> @@ -74,7 +74,7 @@ static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
> static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
> {
> struct i2c_client *client = to_i2c_client(dev);
> - uint8_t buffer[len + 1];
> + uint8_t buffer[256];
>
You chose to change len to 255, probably because this is a uint8_t but
this is way too much for this rtc, it only has 10 consecutive registers.
> buffer[0] = off;
> memcpy(&buffer[1], data, len);
> diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
> index 79e24ea..00e11c1 100644
> --- a/drivers/rtc/rtc-mcp795.c
> +++ b/drivers/rtc/rtc-mcp795.c
> @@ -82,7 +82,7 @@ static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
> {
> struct spi_device *spi = to_spi_device(dev);
> int ret;
> - u8 tx[2 + count];
> + u8 tx[257];
>
> tx[0] = MCP795_WRITE;
> tx[1] = addr;
> --
> 2.7.4
>
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com