Re: BUG: general protection fault in batadv_bla_del_backbone_claims

Xingyu Li
2024-08-29T06:15:07Z

Which line would that be in your build?

Somehow, the bug report does not include the line number in my end.

At the moment, I am unable to reproduce this crash with the provided
reproducer.

Can you reproduce it with it?

Sorry. The above syzkaller reproducer needs the additional support to run it.
But here is a C reproducer:
https://gist.github.com/freexxxyyy/0be5002c45d7f060cb599dd7595cab78

On Sun, Aug 25, 2024 at 9:24 AM Sven Eckelmann <sven@narfation.org> wrote:
>
> On Sunday, 25 August 2024 06:14:48 CEST Xingyu Li wrote:
> > In line 307 of net/batman-adv/bridge_loop_avoidance, when executing
> > "hash = backbone_gw->bat_priv->bla.claim_hash;", it does not check if
> > "backbone_gw->bat_priv==NULL".
>
> Because it cannot be NULL unless something really, really, really bad
> happened. bat_priv will only be set when the gateway gets created using
> batadv_bla_get_backbone_gw(). It never gets unset during the lifetime on the
> backbone gateway.
>
> Maybe Simon has more to say about that.
>
> On Sunday, 25 August 2024 06:14:48 CEST Xingyu Li wrote:
> > RIP: 0010:batadv_bla_del_backbone_claims+0x4e/0x360
>
> Which line would that be in your build?
>
> On Sunday, 25 August 2024 06:14:48 CEST Xingyu Li wrote:
> > Syzkaller reproducer:
>
> At the moment, I am unable to reproduce this crash with the provided
> reproducer.
>
> Can you reproduce it with it? If you can, did you try to perform a bisect
> using the reproducer?
>
> Kind regards,
> Sven

--
Yours sincerely,
Xingyu