* Dmitry Torokhov ([email protected]) wrote:
> On 7/5/06, Henk Vergonet <[email protected]> wrote:
> >On Tue, Jun 27, 2006 at 03:51:43PM -0700, Randy.Dunlap wrote:
> >> On Wed, 28 Jun 2006 00:41:19 +0200 Eric Sesterhenn wrote:
> >> > another off by one spotted by coverity (id #485),
> >> > we loop exactly one time too often
> >> >
> >> > Signed-off-by: Eric Sesterhenn <[email protected]>
> >> >
> >> > --- linux-2.6.17-git11/drivers/usb/input/yealink.c.orig 2006-06-28
> >00:29:46.000000000 +0200
> >> > +++ linux-2.6.17-git11/drivers/usb/input/yealink.c 2006-06-28
> >00:30:04.000000000 +0200
> >> > @@ -350,7 +350,7 @@ static int yealink_do_idle_tasks(struct
> >> > val = yld->master.b[ix];
> >> > if (val != yld->copy.b[ix])
> >> > goto send_update;
> >> > - } while (++ix < sizeof(yld->master));
> >> > + } while (++ix < sizeof(yld->master)-1);
> >
> >Apart from introducing a new bug in the code, the construct is ugly.
> >
> >I would rather see then the more readable:
> >
> > ix++;
> > } while (ix < sizeof(yld->master));
> >
>
> The new code is exactly the same as the old one; however I do not see
> the problem with the old code. Could it be that Coverity got confused
> by prefix vs. postfix increment?
I looked at this code several times too, and tried to reproduce the bug
with the following little program:
#include <string.h>
int main(int argc, char **argv) {
char foo[] = "abcdef";
int i = 0;
foo[strlen(foo)] = 'X';
do {
putchar(foo[i]);
} while (++i < sizeof(foo));
}
Which clearly shows that the terminating '\0' gets printed too,
replaced by the X for better visibility, so the code
runs past the array, or did I fail to replicate the original
code somewhere?
Eric
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