Re: [PATCH net-next v2 8/8] bng_en: implement ndo_get_stats64

[Bhargava Chenna Marreddy]

On Fri, Feb 27, 2026 at 6:52 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Thu, 26 Feb 2026 23:51:33 +0530 Bhargava Marreddy wrote:
> > +     set_bit(BNGE_STATE_READ_STATS, &bn->state);
> > +     /* Make sure bnge_close_core() sees that we are reading stats before
> > +      * we check the BNGE_STATE_OPEN flag.
> > +      */
> > +     smp_mb__after_atomic();
> > +     if (!test_bit(BNGE_STATE_OPEN, &bd->state)) {
> > +             clear_bit(BNGE_STATE_READ_STATS, &bn->state);
> > +             *stats = bn->net_stats_prev;
> > +             return;
> > +     }
>
> There can be multiple concurrent readers. Two enter, first one gets
> stalled second one exits clearing the bit, close frees the memory,
> second reader proceeds to hit the NULL pointers.
>
> Again, please don't try to invent synchronization primitives.
> You can probably use RCU here.

Thanks Jakub.

RCU is a good idea to handle the race.
I will switch to it in the next spin and drop the BNGE_STATE_READ_STATS bit.

Thanks,
Bhargava Marreddy

> --
> pw-bot: cr

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature