Re: [linux-next:master] [net] d288a162dd: canonical_address#:#[##]

[Leon Romanovsky <leon@kernel.org>]

On Wed, Apr 19, 2023 at 10:41:00AM +0200, Eric Dumazet wrote:
> On Wed, Apr 19, 2023 at 7:59 AM Leon Romanovsky <leon@kernel.org> wrote:
> >
> > On Tue, Apr 18, 2023 at 02:43:02PM -0600, David Ahern wrote:
> > > On 4/18/23 10:41 AM, Leon Romanovsky wrote:
> > > > Hi,
> > > >
> > > > I came to the following diff which eliminates the kernel panics,
> > > > unfortunately I can explain only second hunk, but first is required
> > > > too.
> > > >
> > > > diff --git a/net/core/dst.c b/net/core/dst.c
> > > > index 3247e84045ca..750c8edfe29a 100644
> > > > --- a/net/core/dst.c
> > > > +++ b/net/core/dst.c
> > > > @@ -72,6 +72,8 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops,
> > > >         dst->flags = flags;
> > > >         if (!(flags & DST_NOCOUNT))
> > > >                 dst_entries_add(ops, 1);
> > > > +
> > > > +       INIT_LIST_HEAD(&dst->rt_uncached);
> > >
> > > d288a162dd1c73507da582966f17dd226e34a0c0 moved rt_uncached from rt6_info
> > > and rtable to dst_entry. Only ipv4 and ipv6 usages initialize it. Since
> > > it is now in dst_entry, dst_init is the better place so it can be
> > > removed from rt_dst_alloc and rt6_info_init.
> >
> > This is why I placed it there, but the rt_uncached list is initialized
> > in xfrm6 right before first call to rt6_uncached_list_add().
> >
> >    70 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
> >    71                           const struct flowi *fl)
> >    72 {
> > ...
> >    92         INIT_LIST_HEAD(&xdst->u.rt6.dst.rt_uncached);
> >    93         rt6_uncached_list_add(&xdst->u.rt6);
> >
> > My silly explanation is that xfrm6_dst_destroy() can be called before xfrm6_fill_dst().
> >
> > Thanks
> >
> > >
> 
> Please take a look at the fix that was sent yesterday :
> 
> https://patchwork.kernel.org/project/netdevbpf/patch/20230418165426.1869051-1-mbizon@freebox.fr/

Thanks, I replied there with my comments.

> 
> Thanks.