Re: [syzbot ci] Re: tipc: Fix use-after-free in tipc_mon_reinit_self().

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 6 Nov 2025 14:37:10 -0800 Kuniyuki Iwashima wrote:
> > On Thu,  6 Nov 2025 17:59:17 +0000 Kuniyuki Iwashima wrote:  
> > > -void tipc_mon_reinit_self(struct net *net)
> > > +void tipc_mon_reinit_self(struct net *net, bool rtnl_held)
> > >  {
> > >       struct tipc_monitor *mon;
> > >       int bearer_id;
> > >
> > > -     rtnl_lock();
> > > +     if (!rtnl_held)
> > > +             rtnl_lock();  
> >
> > I haven't looked closely but for the record conditional locking
> > is generally considered to be poor code design. Extract the body
> > into a __tipc_mon_reinit_self() helper and call that when lock
> > is already held? And:
> >
> > void tipc_mon_reinit_self(struct net *net)
> > {
> >         rtnl_lock();
> >         __tipc_mon_reinit_self(net);
> >         rtnl_unlock();
> > }  
> 
> That's much cleaner, I'll use this.

After sending I realized you probably want to do this wrapping around
tipc_net_finalize(), otherwise we'd just be shifting the conditional.
But you get the point.. :)