Re: That's pretty much it for 3.5.0

[John Fastabend <john.r.fastabend@xxxxxxxxx>]

On 7/17/2012 12:09 PM, John Fastabend wrote:
> On 7/17/2012 12:00 PM, John Fastabend wrote:
> > On 7/17/2012 11:48 AM, Rustad, Mark D wrote:
> > > On Jul 17, 2012, at 10:41 AM, Rustad, Mark D wrote:
> > >
> > > > On Jul 17, 2012, at 9:01 AM, David Miller wrote:
> > > >
> > > > > Linus was _extremely_ generous and took in all the stuff that was
> > > > > pending in the net tree just now.
> > > >
> > > > Maybe *too* generous. :-) I just updated and when I boot I get an
> > > > early crash in update_netdev_tables which is in netprio_cgroup.c.
> > > >
> > > > > Besides very serious issues, I'm not willing to consider any more bug
> > > > > fixes for the 'net' tree at this time.
> > > >
> > > > I think the above issue will have to be fixed, as it completely
> > > > prevents booting for any kernel that includes the netprio_cgroup
> > > > option.
> > > >
> > > > > Only one pending known bug qualifies, and that's the CIPSO ip option
> > > > > processing OOPS'er.  And I'll work on that myself if Paul Moore
> > > > > doesn't show a sign of life in the next day.
> > > > >
> > > > > Thanks.
> > > >
> > > >
> > > > I can start taking a look at this if you like, but I see that Gao
> > > > feng has two patches in the last set of patches that may be related.
> > > >
> > > > To give you an idea how early the crash is, here are a few log
> > > > messages leading up to it:
> > > >
> > > > [    0.003455] Dentry cache hash table entries: 262144 (order: 9,
> > > > 2097152 bytes)
> > > > [    0.005550] Inode-cache hash table entries: 131072 (order: 8,
> > > > 1048576 bytes)
> > > > [    0.007165] Mount-cache hash table entries: 256
> > > > [    0.010289] Initializing cgroup subsys net_cls
> > > > [    0.010947] Initializing cgroup subsys net_prio
> > > > [    0.011039] BUG: unable to handle kernel NULL pointer dereference
> > > > at 0000000000000828
> > > > [    0.011998] IP: [<ffffffff814202c8>] update_netdev_tables+0x68/0xe0
> > >
> > >
> > > I found that I can avoid the crash by configuring the netprio_cgroup
> > > as a module. I don't need to have it built in, I just happened to.
> > > This finding may lower the temperature of this issue a lot from what I
> > > had been feeling.
> >
> > hmm looks like we access init_net here,
> >
> > static void update_netdev_tables(void)
> > {
> >          struct net_device *dev;
> >          u32 max_len = atomic_read(&max_prioidx) + 1;
> >          struct netprio_map *map;
> >
> >          rtnl_lock();
> >          for_each_netdev(&init_net, dev) {
> >                  map = rtnl_dereference(dev->priomap);
> >                  if ((!map) ||
> >                      (map->priomap_len < max_len))
> >                          extend_netdev_table(dev, max_len);
> >          }
> >          rtnl_unlock();
> > }
> >
> > but inet_net is initialized by pure_initcall(net_ns_init) and I
> > gather pure_initcall's should not have any dependencies but it
> > looks like we created one here with cgroup_init_early() in
> > start_kernel().
> >
> > I'll poke around some more. Also had some off list help from
> > Mark.
> >
> > .John
>
> although we don't have an early_init hook for netprio_cgroup so this
> is probably not correct.

Hey Mark,

you have better timing then me (I can't make this fail). Can you try
cgroup_init below rest_init() in start_kernel(). That's in init/main.c

.John

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