Re: [PATCH] powerpc: signedness bug in update_flash_db()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Mon, Oct 01, 2018 at 08:22:01PM +0200, christophe leroy wrote:
> 
> 
> Le 01/10/2018 à 18:44, Dan Carpenter a écrit :
> > The "count < sizeof(struct os_area_db)" comparison is type promoted to
> > size_t so negative values of "count" are treated as very high values and
> > we accidentally return success instead of a negative error code.
> > 
> > This doesn't really change runtime much but it fixes a static checker
> > warning.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/arch/powerpc/platforms/ps3/os-area.c b/arch/powerpc/platforms/ps3/os-area.c
> > index cdbfc5cfd6f3..f5387ad82279 100644
> > --- a/arch/powerpc/platforms/ps3/os-area.c
> > +++ b/arch/powerpc/platforms/ps3/os-area.c
> > @@ -664,7 +664,7 @@ static int update_flash_db(void)
> >   	db_set_64(db, &os_area_db_id_rtc_diff, saved_params.rtc_diff);
> >   	count = os_area_flash_write(db, sizeof(struct os_area_db), pos);
> > -	if (count < sizeof(struct os_area_db)) {
> > +	if (count < 0 || count < sizeof(struct os_area_db)) {
> 
> Why not simply add a cast ? :
> 
> if (count < (ssize_t)sizeof(struct os_area_db)) {
> 

There are so many ways to solve these and no accounting for taste.  Do
you need me to resend or can you redo it yourself?

regards,
dan carpenter