Re: [PATCH v4] net: sched: convert qdisc linked list to hashtable

[Fengguang Wu]

On Thu, Jul 28, 2016 at 08:53:12PM +0800, Fengguang Wu wrote:
> On Thu, Jul 28, 2016 at 01:18:27PM +0200, Jiri Kosina wrote:
> > On Thu, 28 Jul 2016, kbuild test robot wrote:
> >
> > > [auto build test ERROR on v4.7-rc7]
> > > [also build test ERROR on next-20160728]
> > > [cannot apply to net/master net-next/master ipsec-next/master]
> > > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> > >
> > > url:    https://github.com/0day-ci/linux/commits/Jiri-Kosina/net-sched-convert-qdisc-linked-list-to-hashtable/20160728-182303
> > > config: i386-randconfig-s0-201630 (attached as .config)
> > > compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> > > reproduce:
> > >         # save the attached .config to linux build tree
> > >         make ARCH=i386
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > >    net/built-in.o: In function `dev_activate':
> > > >> (.text+0x37ccb): undefined reference to `qdisc_hash_add'
> >
> > Dear 0-day team,
> >
> > could you please check my question regarding this very build failure here?
> >
> > 	lkml.kernel.org/r/alpine.LNX.2.00.1607141612560.24757@xxxxxxxxxxxxx
>
> Sorry I missed that. For your convenience, here is the answer to the
> original email:
>
> > This issue is be there even without my patch (but with qdisc_list_add
> > instead), isn't it?
>
> Yes it looks so, this number happens in a number of places:
>
> dns_query.c:(.text+0x39b84): undefined reference to `qdisc_hash_add'
> include/linux/netdevice.h:1935: undefined reference to `qdisc_hash_add'
> net/core/netevent.c:31: undefined reference to `qdisc_hash_add'
> net/sched/sch_generic.c:789: undefined reference to `qdisc_hash_add'
> sch_generic.c:(.text+0x33487): undefined reference to `qdisc_hash_add'
> switchdev.c:(.text+0x3bf58): undefined reference to `qdisc_hash_add'
> sysctl_net.c:(.text+0x31f70): undefined reference to `qdisc_hash_add'
> (.text.dev_activate+0x228): undefined reference to `qdisc_hash_add'
> (.text+0x37d0b): undefined reference to `qdisc_hash_add'
> wext-proc.c:(.text+0x390a8): undefined reference to `qdisc_hash_add'

Jiri, I just double checked and find no similar errors related to
qdisc_list_add(). The parent commit 95556a8838 ("dccp: avoid deadlock
in dccp_v4_ctl_send_reset") builds fine without error.

Thanks,
Fengguang

> > The problem is that sch_generic.c (where dev_activate() is) is being
> > compiled everytime CONFIG_NET is set, but sch_api.c (where
> > qdisc_list_add() is defined) only when CONFIG_NET_SCHED is set (and there
> > is no stub for !CONFIG_NET_SCHED case).
>
> So it looks like a more general problem than specific to this patch.
>
> Thanks,
> Fengguang