Re: [PATCH v2] selftests/mm: mlock2-tests: fix fclose(NULL) in is_vmflag_set()

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Fri, Nov 13, 2026 at 11:31:55AM +0100, David Hildenbrand (Arm) wrote:
> On 11/13/26 03:52, Hongfu Li wrote:
> > is_vmflag_set() jumps to the shared 'out' label when
> > seek_to_smaps_entry() fails. smaps is NULL on that path, and the
> > code at the 'out' label calls fclose(smaps) unconditionally.
> > fclose(NULL) is undefined behaviour, so the test crashes before
> > it can report a test result.
>
> I was briefly confuses staring at get_value_for_name() diff below. WHich is
> clarified below.
>
> >
> > Return early on that error path instead, so smaps is always valid
> > at the 'out' label.
> >
> > get_value_for_name() follows the same pattern. Return early on the
> > seek_to_smaps_entry() error path there as well, and drop the now
> > redundant 'if (smaps)' guard on the fclose().
> >
> > Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
>
> Fixes: tag? :)
>
> Apart form that LGTM
>
> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>

Similarly,

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

>
> --
> Cheers,
>
> David

--
Cheers, Lorenzo