Re: [PATCH net] net: dsa: fix panic when port leaves a bridge

["Marek Behún" <kabel@kernel.org>]

On Mon, 14 Mar 2022 16:48:47 +0100
Tobias Waldekranz <tobias@waldekranz.com> wrote:

> On Mon, Mar 14, 2022 at 16:34, Marek Behún <kabel@kernel.org> wrote:
> > Fix a data structure breaking / NULL-pointer dereference in
> > dsa_switch_bridge_leave().
> >
> > When a DSA port leaves a bridge, dsa_switch_bridge_leave() is called by
> > notifier for every DSA switch that contains ports that are in the
> > bridge.
> >
> > But the part of the code that unsets vlan_filtering expects that the ds
> > argument refers to the same switch that contains the leaving port.
> >
> > This leads to various problems, including a NULL pointer dereference,
> > which was observed on Turris MOX with 2 switches (one with 8 user ports
> > and another with 4 user ports).
> >
> > Thus we need to move the vlan_filtering change code to the non-crosschip
> > branch.
> >
> > Fixes: d371b7c92d190 ("net: dsa: Unset vlan_filtering when ports leave the bridge")
> > Reported-by: Jan Bětík <hagrid@svine.us>
> > Signed-off-by: Marek Behún <kabel@kernel.org>
> > ---  
> 
> Hi Marek,
> 
> I ran into the same issue a while back and fixed it (or at least thought
> I did) in 108dc8741c20. Has that been applied to your tree? Maybe I
> missed some tag that caused it to not be back-ported?

It wasn't applied because I was working with net, not net-next.

Very well. We will need to get this backported to stable, though.

Marek