[next-20170124] Kernel oops(rt6_fill_node) during reboot of LPAR

[Sachin Sant]

While rebooting PowerVM LPAR running 4.10.0-rc5-next-20170124
on a POWER8 box, following kernel oops is displayed.

This problem was introduced with next-20170123. next-20170120 works.
Initial analysis points to following patch included with next-20170123

commit a1a22c12060e4b9c52f45d4b3460f614e00162a2
net: ipv6: Keep nexthop of multipath route on admin down


[  OK  ] Stopped Logout off all iSCSI sessions on shutdown.
[  OK  ] Stopped CUPS Printing Service.
[  OK  ] Stopped Dynamic System Tuning Daemon.
[  OK  ] Stopped target Network.
         Stopping LSB: Bring up/down networking...
[   86.292027] Unable to handle kernel paging request for data at address 0x000001d4
[   86.292050] Faulting instruction address: 0xc0000000008734b0
[   86.292054] Oops: Kernel access of bad area, sig: 11 [#1]
[   86.292056] SMP NR_CPUS=2048 
[   86.292057] NUMA 
[   86.292059] pSeries
[   86.292062] Modules linked in: xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun kvm_pr kvm ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm iw_cxgb3 ib_core ghash_generic xts gf128mul tpm_ibmvtpm tpm vmx_crypto sg pseries_rng nfsd auth_rpcgss nfs_acl lockd
[   86.292099]  grace sunrpc ip_tables xfs libcrc32c sr_mod sd_mod cdrom cxgb3 ibmvscsi ibmveth scsi_transport_srp mdio dm_mirror dm_region_hash dm_log dm_mod
[   86.292109] CPU: 0 PID: 1500 Comm: NetworkManager Not tainted 4.10.0-rc5-next-20170124 #1
[   86.292113] task: c00000000319b800 task.stack: c0000000fb9e0000
[   86.292115] NIP: c0000000008734b0 LR: c000000000873444 CTR: c000000000879490
[   86.292118] REGS: c0000000fb9e33d0 TRAP: 0300   Not tainted  (4.10.0-rc5-next-20170124)
[   86.292121] MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE>
[   86.292124]   CR: 28004428  XER: 00000000
[   86.292128] CFAR: c000000000008850 DAR: 00000000000001d4 DSISR: 40000000 SOFTE: 1 
[   86.292128] GPR00: c000000000873444 c0000000fb9e3650 c000000000ff9f00 0000000000000000 
[   86.292128] GPR04: c0000000fb9e36b4 0000000000000004 c00000026ff50024 0000000000007e80 
[   86.292128] GPR08: 0000000000000000 0000000000000000 0000000000000002 0000000000000014 
[   86.292128] GPR12: c000000000879490 c00000000e800000 0000000000000000 0000000000000000 
[   86.292128] GPR16: 0000000000000000 0000000000000000 0000000000000000 c000000000fa6d00 
[   86.292128] GPR20: 0000000000000000 c000000000fa6d00 0000000000000000 c00000026a5bba00 
[   86.292128] GPR24: c000000000fa6d00 0000000000000000 0000000000000000 00000000384005dc 
[   86.292128] GPR28: 0000000000000000 c00000026a5bba00 c000000279f71c00 c00000026ff50000 
[   86.292163] NIP [c0000000008734b0] rt6_fill_node.isra.42+0x150/0x640
[   86.292166] LR [c000000000873444] rt6_fill_node.isra.42+0xe4/0x640
[   86.292169] Call Trace:
[   86.292171] [c0000000fb9e3650] [c000000000873444] rt6_fill_node.isra.42+0xe4/0x640 (unreliable)
[   86.292175] [c0000000fb9e3710] [c000000000878718] rt6_dump_route+0x68/0xa0
[   86.292178] [c0000000fb9e3780] [c0000000008794d8] fib6_dump_node+0x48/0xb0
[   86.292182] [c0000000fb9e37b0] [c000000000878de8] fib6_walk_continue+0x1d8/0x200
[   86.292185] [c0000000fb9e3800] [c000000000879134] fib6_walk+0x44/0xa0
[   86.292189] [c0000000fb9e3840] [c00000000087a0f4] inet6_dump_fib+0x1f4/0x2d0
[   86.292193] [c0000000fb9e38f0] [c0000000007ae9cc] netlink_dump+0x14c/0x370
[   86.292196] [c0000000fb9e3940] [c0000000007af428] __netlink_dump_start+0x198/0x210
[   86.292201] [c0000000fb9e3990] [c0000000007833f4] rtnetlink_rcv_msg+0x194/0x300
[   86.292204] [c0000000fb9e3a10] [c0000000007b1e48] netlink_rcv_skb+0x128/0x140
[   86.292208] [c0000000fb9e3a50] [c00000000077f46c] rtnetlink_rcv+0x3c/0x60
[   86.292211] [c0000000fb9e3a80] [c0000000007b13dc] netlink_unicast+0x1ec/0x370
[   86.292215] [c0000000fb9e3ae0] [c0000000007b1adc] netlink_sendmsg+0x40c/0x480
[   86.292219] [c0000000fb9e3b70] [c00000000073caec] sock_sendmsg+0x5c/0x90
[   86.292223] [c0000000fb9e3ba0] [c00000000073d79c] ___sys_sendmsg+0x31c/0x330
[   86.292226] [c0000000fb9e3d30] [c00000000073ece4] __sys_sendmsg+0x54/0xc0
[   86.292229] [c0000000fb9e3dd0] [c00000000073f88c] SyS_socketcall+0x35c/0x3e0
[   86.292234] [c0000000fb9e3e30] [c00000000000b184] system_call+0x38/0xe0
[   86.292236] Instruction dump:
[   86.292238] 39200000 913f0018 e93e0018 e9490048 794807e1 41820010 e9290048 792af7e3 
[   86.292243] 41820024 39200010 913f0018 e93e0158 <812901d4> 2f890000 419e000c 39200011 
[   86.292249] ---[ end trace 6bc185aea0ad63a6 ]---
[   86.292251] 
[   88.292296] Kernel panic - not syncing: Fatal exception in interrupt
[   88.292399] Rebooting in 10 seconds..