On Tue, 9 Sep 2014 23:25:28 +0200 (CEST) Jiri Kosina <jkosina@xxxxxxx> wrote:
> kfree() is happy to accept NULL pointer and does nothing in such case.
> It's reasonable to expect it to behave the same if ERR_PTR is passed to
> it.
>
> Inspired by a9cfcd63e8d ("ext4: avoid trying to kfree an ERR_PTR
> pointer").
>
> ...
>
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3612,7 +3612,7 @@ void kfree(const void *objp)
>
> trace_kfree(_RET_IP_, objp);
>
> - if (unlikely(ZERO_OR_NULL_PTR(objp)))
> + if (unlikely(ZERO_OR_NULL_PTR(objp) || IS_ERR(objp)))
> return;
kfree() is quite a hot path to which this will add overhead. And we
have (as far as we know) no code which will actually use this at
present.
How about a new
kfree_safe(...)
{
if (IS_ERR(...))
return;
if (other-stuff-when-we-think-of-it)
return;
kfree(...);
}
?
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