Re: [PATCH v4] gpio: sim: fix an invalid __free() usage

Andy Shevchenko
2023-09-19T10:50:19Z

On Tue, Sep 19, 2023 at 12:31:36AM -0700, brgl@bgdev.pl wrote:
> On Mon, 18 Sep 2023 17:31:36 +0200, Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> said:
> > On Mon, Sep 18, 2023 at 04:55:33PM +0200, Bartosz Golaszewski wrote:

...

> > Of course this can be replace with...
> >
> >> + line_names = kcalloc(line_names_size, sizeof(*line_names),
> >> + GFP_KERNEL);
> >
> >> + if (!line_names)
> >
> > ZERO_OR_NULL_PTR() check here, but I assume we discourage use of it.
>
> Why? There are less than 40 instances of using it in the kernel. kmalloc()
> returns NULL on failure.

Nope, k*alloc*() returns ZERO or NULL on failure. That's what most developers
are missing :-)

> >> + return ERR_PTR(-ENOMEM);

Hence either one needs to check for 0 the size given to the kmalloc(),
_or_ to check for all possible return values from it.

--
With Best Regards,
Andy Shevchenko