Re: Namespaced network devices not cleaned up properly after execution of pmtu.sh kernel selftest

[Mitchell Augustin]

> As I said before, we were aware of this issue, well before your report.

Yes, sorry - to clarify, I wasn't commenting on the state of the bug
itself, just asking whether my reproducer is helpful in exposing it
more easily/reliably and on more systems than other known methods, per
Jakub's original request.

In any case, thank you for the additional context on the bug itself though.

-Mitchell Augustin

On Mon, Sep 23, 2024 at 3:14 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
>
> On Mon, Sep 23, 2024 at 10:01 PM Mitchell Augustin
> <mitchell.augustin@xxxxxxxxxxxxx> wrote:
> >
> > Hi!
> >
> > I'm wondering if anyone has taken a look at my reproducer yet. I'd
> > love to know if it has helped any of you reproduce the bug more
> > easily.
> >
> > Patch w/ reproducer:
> > https://lore.kernel.org/all/20240916191857.1082092-1-mitchell.augustin@xxxxxxxxxxxxx/
> >
>
> As I said before, we were aware of this issue, well before your report.
>
> We have no efficient fix yet.
> https://lore.kernel.org/netdev/202405311808.vqBTwxEf-lkp@xxxxxxxxx/T/
>
> You can disable dst_cache, this should remove the issue.
>
> diff --git a/net/core/dst_cache.c b/net/core/dst_cache.c
> index 70c634b9e7b02300188582a1634d5977838db132..53351ff58b35dbee37ff587f7ef8f72580d9e116
> 100644
> --- a/net/core/dst_cache.c
> +++ b/net/core/dst_cache.c
> @@ -142,12 +142,7 @@ EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
>
>  int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
>  {
> -       dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
> -                                           gfp | __GFP_ZERO);
> -       if (!dst_cache->cache)
> -               return -ENOMEM;
> -
> -       dst_cache_reset(dst_cache);
> +       dst_cache->cache = NULL;
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(dst_cache_init);



-- 
Mitchell Augustin
Software Engineer - Ubuntu Partner Engineering