Re: [PATCH v2] mm: do not try to migrate lru_gen if it's not associated with a memcg

[David Hildenbrand]

On 16.01.23 00:13, Yu Zhao wrote:
> On Sun, Jan 15, 2023 at 6:47 AM msizanoen1 <msizanoen@xxxxxxxxxxx> wrote:
> > In some cases, memory cgroup migration can be initiated by userspace
> > right after a process was created and right before `lru_gen_add_mm()` is
> > called (e.g. by some program watching a cgroup and moving away any
> > processes it detects[1]), which results in the following sequence of
> > WARNs followed by an Oops as the kernel attempts to perform a
> > `lru_gen_add_mm()` twice on the same `mm`:
>
> ...
>
> > Fix this by simply leaving the lru_gen alone if it has not been
> > associated with a memcg yet, as it should eventually be assigned to the
> > right cgroup anyway.
> >
> > [1]: https://gitlab.freedesktop.org/benzea/uresourced/-/blob/master/cgroupify/cgroupify.c
> >
> > v2:
> >          Added stable cc tags
> >
> > Signed-off-by: N/A (patch should not be copyrightable)
> > Cc: stable@xxxxxxxxxxxxxxx
>
> Thanks for the fix.  Cc'ing stable is the right thing to do. The
> commit message and the comment styles could be easily adjusted to
> align with the guidelines.
>
> I don't think the N/A is acceptible though. I fully respect it if you
> wish to remain anonymous -- I can send a similar fix crediting you
> as the "anonymous user <msizanoen@xxxxxxxxxxx>" who reported this bug.

Not acceptable:

Documentation/process/submitting-patches.rs

"using your real name (sorry, no pseudonyms or anonymous contributions.)"


--
Thanks,

David / dhildenb