netdev - Re: RESEND: Easily reproducible kernel panic due to netdev all_adj

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Message-ID: <56F5B746.9050401@cradlepoint.com>
Date:	Fri, 25 Mar 2016 16:10:14 -0600
From:	Andrew Collins <acollins@...dlepoint.com>
To:	Matthias Schiffer <mschiffer@...verse-factory.net>
CC:	<netdev@...r.kernel.org>
Subject: Re: RESEND: Easily reproducible kernel panic due to netdev
 all_adj_list refcnt handling

On 03/25/2016 02:43 PM, Matthias Schiffer wrote:
> We've tried your patch, and it changes the symptoms a bit, but doesn't fix
> the panic. I've attached kernel logs of the crash both before and after
> applying the patch.
>
> One note: I did not reproduce this issue myself, it was first reported in
> [1], and then forwarded to the batman-adv issue tracker [2] by me.
>
> Regards,
> Matthias
>
>
> [1] https://github.com/freifunk-gluon/gluon/issues/680
> [2] https://www.open-mesh.org/issues/247

On the off chance it helps, the version of the patch I integrated locally takes a somewhat different approach
than the one I sent to the mailing list (propagates adj_list refcnts).  I've attached it in case it's useful.

I haven't submitted this upstream yet as it's still rather ugly.  I'm of the opinion that the whole "every device
knows every upperdev and lowerdev in its tree" model is rather broken, and the patch is just working around
a design that needs some rework.

Thanks,
Andrew Collins

View attachment "netdev_ref_cnt.patch" of type "text/x-patch" (8963 bytes)