Kernel panic at vsnprintf in reading /proc/cpuinfo

Issue

• Kernel panic:

BUG: unable to handle kernel paging request at ffffffffff8178df
IP: [<ffffffff81275363>] vsnprintf+0x313/0x5f0
PGD 1a87067 PUD 1a88067 PMD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/devices/system/cpu/cpu23/topology/thread_siblings
CPU 1 
Modules linked in: fuse ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables bridge stp llc bonding ipv6 vfat fat dm_round_robin dm_multipath vhost_net macvtap macvlan tun kvm_intel kvm uinput ics932s401 i2c_core microcode ses enclosure cdc_ether usbnet mii iTCO_wdt iTCO_vendor_support shpchp sg igb dca ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif ahci wmi qla2xxx scsi_transport_fc scsi_tgt megaraid_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]

Pid: 3510, comm: libvirtd Not tainted 2.6.32-220.el6.x86_64 #1 IBM IBM System x3650 M4: -[7915AC1]-/00Y8473
RIP: 0010:[<ffffffff81275363>]  [<ffffffff81275363>] vsnprintf+0x313/0x5f0
RSP: 0018:ffff880867c6bcb8  EFLAGS: 00010292
RAX: ffff880735f96278 RBX: ffff880735f96278 RCX: 0000000000000061
RDX: ffff880735f96278 RSI: 00000000fffffffe RDI: 0000000000000003
RBP: ffff880867c6bd48 R08: 0000000000000073 R09: 00000000fffffffd
R10: 0000000000000001 R11: 0000000000000293 R12: ffffffffff8178df
R13: ffffffff8178dfc8 R14: ffff880867c6bd58 R15: ffff880735f97000
FS:  00007f246d415700(0000) GS:ffff880028220000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff8178df CR3: 0000001069888000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process libvirtd (pid: 3510, threadinfo ffff880867c6a000, task ffff880867524080)
Stack:
 0000000000000004 0000000affffffff ffffffffffffffff ffff88086bd6d800
<0> 0000000000000001 35f962746450b078 0000000000000d8c ffff880735f96274
<0> 0000000000000004 0000000affffffff ffffffffffffffff ffff880867c6bd78
Call Trace:
 [<ffffffff81198b68>] seq_printf+0x58/0x90
 [<ffffffff8127902c>] ? __bitmap_weight+0x8c/0xb0
 [<ffffffff81019f16>] show_cpuinfo+0x236/0x430
 [<ffffffff81198e65>] seq_read+0xe5/0x3f0
 [<ffffffff811daf4e>] proc_reg_read+0x7e/0xc0
 [<ffffffff81176e15>] vfs_read+0xb5/0x1a0
 [<ffffffff81176f51>] sys_read+0x51/0x90
 [<ffffffff8100b0f2>] system_call_fastpath+0x16/0x1b
Code: 48 8b 55 b0 48 89 df 4c 89 fe 48 89 14 24 48 8b 55 b8 48 89 54 24 08 48 8b 55 c0 48 89 54 24 10 48 8b 10 e8 d0 ec ff ff 48 89 c3 <41> 0f b6 04 24 e9 c4 fd ff ff 0f 1f 00 41 8b 16 83 fa 2f 0f 87 
RIP  [<ffffffff81275363>] vsnprintf+0x313/0x5f0
 RSP <ffff880867c6bcb8>
CR2: ffffffffff8178df