On Mon, Jan 22, 2018 at 01:27:54PM +0300, Dan Carpenter wrote:
> The main problem is that the parentheses are in the wrong place and the
> unlikely() call returns either 0 or 1 so it's never less than zero.
Doh, thanks, yes. Seems worth considering a grammar rule for it.
> The other problem is that signed integer overflows like "INT_MAX + 1" are
> undefined behavior.
Likewise.
This seems like another possible generic typo issue. But I would not resolve it
the way you did, in this particular case below num_test_devs represents the
number of already registered devs, before we increment. So the way to resolve
this would be:
if (num_test_devs + 1 == INT_MAX)
I'll get this upstream, thanks!
Luis
> Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> diff --git a/lib/test_kmod.c b/lib/test_kmod.c
> index e372b97eee13..30fd6d9e5361 100644
> --- a/lib/test_kmod.c
> +++ b/lib/test_kmod.c
> @@ -1141,7 +1141,7 @@ static struct kmod_test_device *register_test_dev_kmod(void)
> mutex_lock(®_dev_mutex);
>
> /* int should suffice for number of devices, test for wrap */
> - if (unlikely(num_test_devs + 1) < 0) {
> + if (num_test_devs == INT_MAX) {
> pr_err("reached limit of number of test devices\n");
> goto out;
> }
>
--
Luis Rodriguez, SUSE LINUX GmbH
Maxfeldstrasse 5; D-90409 Nuernberg
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