On Tue, 8 Oct 2024 at 09:13, Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
>
> On Mon, Oct 7, 2024 at 8:09 PM Christophe JAILLET
> <christophe.jaillet@xxxxxxxxxx> wrote:
> >
> > Le 07/10/2024 à 13:45, Bartosz Golaszewski a écrit :
> > > From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > >
> > > 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));
> > >
> > > Increase the size of the target buffer.
> > >
> > > Fixes: 15a0580ced08 ("mmc_spi host driver")
> > > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > > ---
> > > drivers/mmc/host/mmc_spi.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> > > index 8fee7052f2ef..fa1d1a1b3142 100644
> > > --- a/drivers/mmc/host/mmc_spi.c
> > > +++ b/drivers/mmc/host/mmc_spi.c
> > > @@ -222,7 +222,7 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
> > > u8 leftover = 0;
> > > unsigned short rotator;
> > > int i;
> > > - char tag[32];
> > > + char tag[43];
> > >
> > > snprintf(tag, sizeof(tag), " ... CMD%d response SPI_%s",
> > > cmd->opcode, maptype(cmd));
> >
> > 'tag' is only used in a dev_dbg() at the end of the function.
> >
> > Maybe " ... CMD%d response SPI_%s" could me moved directly within the
> > dev_dbg(). This would save a few bytes on the stack, save a snprintf()
> > in the normal path and fix the warning without the need of magic number.
> >
> > just my 2c.
> >
> > CJ
>
> I would be hesitant to change this logic here. The cmd struct is
> manipulated pretty extensively later in the function which leads me to
> believe that this snprintf() here was done on purpose.
The cmd->opcode and cmd->flags aren't really something a host driver
should need to change. It's the core that sets them to inform the host
driver about the command.
I looked closer and it seems to be correct in this case too.
Kind regards
Uffe
