[next 20170227] Memory hot plug results in kernel BUG at mm/memory_hotplug.c:2180!

[Sachin Sant]

Trying to add memory via DLPAR operation on a POWER 8 LPAR running
today’s next results in a crash.

This problem was introduced in today’s next. Possible cause is following commit:
dc18d706a4367 : memory-hotplug: use dev_online for memhp_auto_online

[   42.377988] rpaphp: RPA HOT Plug PCI Controller Driver version: 0.1
[root at alp12 ~]# [  115.179128] pseries-hotplug-mem: Attempting to hot-add 60 LMB(s)
[  115.194879] Unable to resize hash page table to target order 24: -19
[  115.195267] Built 2 zonelists in Node order, mobility grouping on.  Total pages: 240639
[  115.195271] Policy zone: DMA
[  115.196128] Built 2 zonelists in Node order, mobility grouping on.  Total pages: 244735
[  115.196131] Policy zone: DMA
[  115.196209] removing memory fails, because memory [0x00000003c0000000-0x00000003cfffffff] is onlined
[  115.196219] ------------[ cut here ]------------
[  115.196221] kernel BUG at mm/memory_hotplug.c:2180!
[  115.196225] Oops: Exception in kernel mode, sig: 5 [#1]
[  115.196227] SMP NR_CPUS=2048 
[  115.196227] NUMA 
[  115.196229] pSeries
[  115.196232] Modules linked in: rpadlpar_io rpaphp iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp tun bridge stp llc kvm iptable_filter vmx_crypto pseries_rng rng_core binfmt_misc nfsd ip_tables x_tables autofs4
[  115.196254] CPU: 0 PID: 67 Comm: kworker/u33:2 Tainted: G        W       4.10.0-next-20170227 #1
[  115.196260] Workqueue: pseries hotplug workque pseries_hp_work_fn
[  115.196263] task: c0000003b903c200 task.stack: c0000003b90fc000
[  115.196266] NIP: c0000000018789d0 LR: c000000001878958 CTR: c000000001cefb50
[  115.196269] REGS: c0000003b90ff7a0 TRAP: 0700   Tainted: G        W        (4.10.0-next-20170227)
[  115.196272] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>
[  115.196277]   CR: 42002022  XER: 00000009
[  115.196281] CFAR: c00000000187895c SOFTE: 1 
[  115.196281] GPR00: c000000001878958 c0000003b90ffa20 c00000000266c300 0000000000000001 
[  115.196281] GPR04: c0000003ab85ec80 0000000000000068 0000000000000002 0000000000000003 
[  115.196281] GPR08: 0000000000000003 0000000000000003 0000000000000003 00000000000001a3 
[  115.196281] GPR12: 0000000000002200 c00000000ea80000 c0000000016b4848 c0000003b9c30000 
[  115.196281] GPR16: 0000000000000000 0000000000000010 c0000003bfff1a10 c0000003bfff1ae0 
[  115.196281] GPR20: c0000003b82b3b44 0000000000000004 0000000000000002 0000000000000010 
[  115.196281] GPR24: 0000000000000004 0000000000000002 0000000000000000 0000000000000001 
[  115.196281] GPR28: 0000000000000001 0000000000000000 0000000010000000 00000003c0000000 
[  115.196317] NIP [c0000000018789d0] remove_memory+0xe0/0xf0
[  115.196320] LR [c000000001878958] remove_memory+0x68/0xf0
[  115.196322] Call Trace:
[  115.196324] [c0000003b90ffa20] [c000000001878958] remove_memory+0x68/0xf0 (unreliable)
[  115.196329] [c0000003b90ffa60] [c00000000165d294] dlpar_add_lmb+0x394/0x410
[  115.196333] [c0000003b90ffb40] [c00000000165e004] dlpar_memory+0x644/0xd80
[  115.196336] [c0000003b90ffbf0] [c000000001656968] handle_dlpar_errorlog+0xe8/0x150
[  115.196340] [c0000003b90ffc60] [c000000001656a04] pseries_hp_work_fn+0x34/0x90
[  115.196345] [c0000003b90ffc90] [c0000000016aca44] process_one_work+0x174/0x490
[  115.196349] [c0000003b90ffd20] [c0000000016acdf8] worker_thread+0x98/0x530
[  115.196352] [c0000003b90ffdc0] [c0000000016b498c] kthread+0x14c/0x190
[  115.196357] [c0000003b90ffe30] [c0000000015cbc60] ret_from_kernel_thread+0x5c/0x7c
[  115.196360] Instruction dump:
[  115.196362] 3863d2e8 fb89d2e0 4872c231 60000000 38210040 e8010010 eb81ffe0 eba1ffe8 
[  115.196368] ebc1fff0 ebe1fff8 7c0803a6 4e800020 <0fe00000> 00000000 00000000 00000000 
[  115.196374] ---[ end trace c012fadf5f8c4e40 ]---
[  115.196376] 

Thanks
-Sachin