Re: [s390] networking related oops during boot on Hercules (was:build failure)

From: Stephen Hemminger
Date: Wed Nov 28 2007 - 13:43:31 EST


On Wed, 28 Nov 2007 10:26:36 -0700
ebiederm@xxxxxxxxxxxx (Eric W. Biederman) wrote:

> Christian Borntraeger <borntraeger@xxxxxxxxxx> writes:
>
> > Am Mittwoch, 28. November 2007 schrieb Frans Pop:
> > [...]
> >> During boot I get the following oops in the Hercules emulator.
> >> 2.6.22 runs fine on Hercules; I've not tried .23 on it.
> > [...]
> >> ------------ cut here !------------
> >> kernel BUG at net/core/dev.c:852 +
> >> illegal operation: 0001 #1!
> >> Modules linked in: ctc fsm tape_34xx cu3088 tape ccwgroup tape_class dm_mirror
> > d
> >> m_snapshot dm_mod dasd_eckd_mod dasd_mod
> >> CPU: 1 Not tainted
> >> Process hwup (pid: 990, task: 0f034c00, ksp: 0f305be0)
> >> Krnl PSW : 070c0000 8019d0da (dev_alloc_name+0x1e/0x58)
> >> R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0
> >> Krnl GPRS: 00132700 00000000 0f398800 0f398800
> >> 00000000 80132796 0f305d7a 00000002
> >> 0f1ada00 0f3c1f08 0f3c1f00 0f398800
> >> 0f398800 8019d0c2 0f305ca0 0f305c30
> >> Krnl Code: 8019d0cc: f000bf1f2460 srp 3871(1,%r11),1120(%r2),0
> >> 8019d0d2: a7740004 brc 7,8019d0da
> >> 8019d0d6: a7f40001 brc 15,8019d0d8
> >> >8019d0da: 5810d04e l %r1,78(%r13)
> >> 8019d0de: 41a0f060 la %r10,96(%r15)
> >> 8019d0e2: 5820c460 l %r2,1120(%r12)
> >> 8019d0e6: 184a lr %r4,%r10
> >> 8019d0e8: 0de1 basr %r14,%r1
> >> Call Trace:
> >> ( <0000000000000000>! _ehead+0xfffee000/0x80)
> >> <000000000019d710>! register_netdev+0x34/0x6c
> >> <00000000108a561e>! ctc_new_device+0x3ee/0x590 ctc!
> >> <0000000010861398>! ccwgroup_online_store+0xb0/0x13c ccwgroup!
> >> <00000000000c962a>! sysfs_write_file+0xca/0x130
> >> <00000000000840e6>! vfs_write+0x92/0x128 +
> >> <00000000000847e8>! sys_write+0x40/0x70
> >> <000000000002098a>! sysc_do_restart+0x12/0x16
> >> <0000000077f0abaa>! 0x77f0abaa
> >
> >
> > This seems to be related to the new network namespace code by Eric
> > Biederman (CCed). Can you try the following (untested) patch? I also
> > CCed Ursula and Peter as they know the ctc code better than me.
>
> Can you instead change the allocation to be alloc_netdev instead of
> just a plain old kzalloc. That will fix the problem in a much
> more forward compatible way. The current code is also going to
> have problems with dynamically sized array at the end of struct
> net_device.
>
> You ought to also be able to make the allocation unconditional
> as that function only has one caller and it does not pass in
> a struct net_device.
>
> Eric
>

Any code that calls register_netdev with a kzalloc'd pointer is
fundamentally flawed. Read Documentation/networking/netdevices

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