Issue

• System is crashing when memory hot-add executed on Hyper-V guest

BUG: unable to handle kernel NULL pointer dereference at (null) 
IP: [<c052e233>] mem_cgroup_get_reclaim_stat_from_page+0x13/0x50 
*pdpt = 0000000030316001 *pde = 000000007df40067 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/firmware/memmap/5/type 
Modules linked in: nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables autofs4 ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6ta 
ble_filter ip6_tables ipv6 hv_balloon hid_hyperv hv_netvsc hv_utils microcode sg hyperv_fb i2c_piix4 i2c_core ext4 jbd2 mbcache sd_mod crc_t10dif hv_storvsc 
sr_mod cdrom hv_vmbus pata_acpi ata_generic ata_piix dm_mirror dm_region_hash dm_log dm_mod [last unloaded: mperf]

Pid: 1789, comm: snmpd Not tainted 2.6.32-431.5.1.el6.i686 #1 Microsoft Corporation Virtual Machine/Virtual Machine 
EIP: 0060:[<c052e233>] EFLAGS: 00210046 CPU: 0 
EIP is at mem_cgroup_get_reclaim_stat_from_page+0x13/0x50 
EAX: 00000000 EBX: f8c98fe0 ECX: 0045dff8 EDX: 00000000 
ESI: 00000000 EDI: 00000001 EBP: c2e05a60 ESP: f19cbef8 
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 
Process snmpd (pid: 1789, ti=f19ca000 task=f6716550 task.ti=f19ca000) 
Stack: 
c0ac69c0 c04fc78d f8c98fe0 c0ac69c0 00000001 c04fd1ea 00000001 00000001 
<0> 00000001 00000002 00000000 00000008 c2e05a60 00000001 00000000 f0af643c 
<0> c04fd359 f184ecd4 f184375c f6623200 c0513071 f184375c c05128d5 000b77b7 
Call Trace: 
[<c04fc78d>] ? update_page_reclaim_stat+0x1d/0x60 
[<c04fd1ea>] ? ____pagevec_lru_add+0xca/0x140 
[<c04fd359>] ? lru_add_drain+0x59/0x90 
[<c0513071>] ? unmap_region+0x31/0x100 
[<c05128d5>] ? __split_vma+0xe5/0x1e0 
[<c0513303>] ? do_munmap+0x1c3/0x2f0 
[<c051346c>] ? sys_munmap+0x3c/0x60 
[<c04099bf>] ? sysenter_do_call+0x12/0x28 
Code: 24 04 8b 7c 24 08 83 c4 0c c3 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 53 89 c3 a1 80 4f ae c0 85 c0 75 0c 89 d8 e8 8d 3f 00 00 <f6> 00 04 75 08 31 c0 
5b c3 8d 74 26 00 8b 13 8b 40 04 c1 ea 17 
EIP: [<c052e233>] mem_cgroup_get_reclaim_stat_from_page+0x13/0x50 SS:ESP 0068:f19cbef8 
CR2: 0000000000000000