[PATCH v2] mmc: mmc_spi: drop buggy snprintf()

[PATCH v2] mmc: mmc_spi: drop buggy snprintf()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

GCC 13 complains about the truncated output of snprintf():

drivers/mmc/host/mmc_spi.c: In function ‘mmc_spi_response_get’:
drivers/mmc/host/mmc_spi.c:227:64: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
  227 |         snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
      |                                                                ^
drivers/mmc/host/mmc_spi.c:227:9: note: ‘snprintf’ output between 26 and 43 bytes into a destination of size 32
  227 |         snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  228 |                 cmd->opcode, maptype(cmd));

Drop it and fold the string it generates into the only place where it's
emitted - the dev_dbg() call at the end of the function.

Fixes: 15a0580ced08 ("mmc_spi host driver")
Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
- instead of fixing the buffer size, just drop the snprintf() call
  altogether

 drivers/mmc/host/mmc_spi.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 8fee7052f2ef..47443fb5eb33 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -222,10 +222,6 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
 	u8 	leftover = 0;
 	unsigned short rotator;
 	int 	i;
-	char	tag[32];
-
-	snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
-		cmd->opcode, maptype(cmd));
 
 	/* Except for data block reads, the whole response will already
 	 * be stored in the scratch buffer.  It's somewhere after the
@@ -378,8 +374,9 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
 	}
 
 	if (value < 0)
-		dev_dbg(&host->spi->dev, "%s: resp %04x %08x\n",
-			tag, cmd->resp[0], cmd->resp[1]);
+		dev_dbg(&host->spi->dev,
+			"  ... CMD%d response SPI_%s: resp %04x %08x\n",
+			cmd->opcode, maptype(cmd), cmd->resp[0], cmd->resp[1]);
 
 	/* disable chipselect on errors and some success cases */
 	if (value >= 0 && cs_on)
-- 
2.43.0

Re: [PATCH v2] mmc: mmc_spi: drop buggy snprintf()

[Ulf Hansson]

On Tue, 8 Oct 2024 at 18:01, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> GCC 13 complains about the truncated output of snprintf():
>
> drivers/mmc/host/mmc_spi.c: In function ‘mmc_spi_response_get’:
> drivers/mmc/host/mmc_spi.c:227:64: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
>   227 |         snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
>       |                                                                ^
> drivers/mmc/host/mmc_spi.c:227:9: note: ‘snprintf’ output between 26 and 43 bytes into a destination of size 32
>   227 |         snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   228 |                 cmd->opcode, maptype(cmd));
>
> Drop it and fold the string it generates into the only place where it's
> emitted - the dev_dbg() call at the end of the function.
>
> Fixes: 15a0580ced08 ("mmc_spi host driver")
> Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Applied for next, thanks!

Kind regards
Uffe


> ---
> - instead of fixing the buffer size, just drop the snprintf() call
>   altogether
>
>  drivers/mmc/host/mmc_spi.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> index 8fee7052f2ef..47443fb5eb33 100644
> --- a/drivers/mmc/host/mmc_spi.c
> +++ b/drivers/mmc/host/mmc_spi.c
> @@ -222,10 +222,6 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
>         u8      leftover = 0;
>         unsigned short rotator;
>         int     i;
> -       char    tag[32];
> -
> -       snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
> -               cmd->opcode, maptype(cmd));
>
>         /* Except for data block reads, the whole response will already
>          * be stored in the scratch buffer.  It's somewhere after the
> @@ -378,8 +374,9 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
>         }
>
>         if (value < 0)
> -               dev_dbg(&host->spi->dev, "%s: resp %04x %08x\n",
> -                       tag, cmd->resp[0], cmd->resp[1]);
> +               dev_dbg(&host->spi->dev,
> +                       "  ... CMD%d response SPI_%s: resp %04x %08x\n",
> +                       cmd->opcode, maptype(cmd), cmd->resp[0], cmd->resp[1]);
>
>         /* disable chipselect on errors and some success cases */
>         if (value >= 0 && cs_on)
> --
> 2.43.0
>