Kernel panic with "BUG at lib/prio_tree.c:150!"

Issue

• Kernel crashed with following calltraces :

------------[ cut here ]------------
kernel BUG at lib/prio_tree.c:150!
invalid opcode: 0000 [#1] SMP 
last sysfs file: /sys/devices/system/cpu/online
CPU 1 
Modules linked in: tcp_diag inet_diag mptctl mptbase zing_mm(U) autofs4 nfs lockd fscache auth_rpcgss nfs_acl sunrpc bonding ipv6 dm_multipath iTCO_wdt iTCO_vendor_support microcode ipmi_devintf power_meter acpi_ipmi ipmi_si ipmi_msghandler serio_raw sb_edac edac_core i2c_i801 lpc_ich mfd_core tg3 hpilo hpwdt ioatdma dca sfc i2c_algo_bit i2c_core ptp pps_core mdio sg ext4 jbd2 mbcache dm_snapshot dm_bufio sd_mod crc_t10dif xhci_hcd hpsa wmi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]

Pid: 8628, comm: python Not tainted 2.6.32-696.3.1.el6.x86_64 #1 HP ProLiant DL380 Gen9
RIP: 0010:[<ffffffff8129f8d5>]  [<ffffffff8129f8d5>] prio_tree_replace+0x75/0x80
RSP: 0018:ffff8873a311bd08  EFLAGS: 00010286
RAX: ffff8818d9dfca30 RBX: ffff8817171c21b8 RCX: ffff885fe83f6750
RDX: ffff885fe83f6750 RSI: ffff8818d9dfca30 RDI: ffff8817171c21b8
RBP: ffff8873a311bd08 R08: 000000000000007d R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8818d9dfca30
R13: ffff8874106d52c0 R14: ffff8817171c2198 R15: 0000592000000000
FS:  00007fa4d962e700(0000) GS:ffff880028240000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007fa5ae495814 CR3: 00000018ad587000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process python (pid: 8628, threadinfo ffff8873a3118000, task ffff8873a3df3520)
Stack:
 ffff8873a311bd28 ffffffff8129f98f 0000000000000000 ffff8817171c21d8
<d> ffff8873a311bd48 ffffffff8114f7e0 ffff8818d9dfc9e0 ffff8817171c21d8
<d> ffff8873a311bd58 ffffffff8115dde1 ffff8873a311bd88 ffffffff8115de50
Call Trace:
 [<ffffffff8129f98f>] prio_tree_remove+0xaf/0xe0
 [<ffffffff8114f7e0>] vma_prio_tree_remove+0x80/0x110
 [<ffffffff8115dde1>] __remove_shared_vm_struct+0x41/0x60
 [<ffffffff8115de50>] unlink_file_vma+0x50/0x70
 [<ffffffff811561b0>] free_pgtables+0x50/0x120
 [<ffffffff8115d890>] exit_mmap+0xb0/0x180
 [<ffffffff81079a1c>] mmput+0x6c/0x120
 [<ffffffff81209b42>] proc_pid_cmdline_read+0x242/0x570
 [<ffffffff8123ad26>] ? security_file_permission+0x16/0x20
 [<ffffffff8119a585>] vfs_read+0xb5/0x1a0
 [<ffffffff8119b35f>] ? fget_light_pos+0x3f/0x50
 [<ffffffff8119a8d1>] sys_read+0x51/0xb0
 [<ffffffff8100b0d2>] system_call_fastpath+0x16/0x1b
Code: 46 08 48 89 50 10 48 89 f0 c9 c3 0f 1f 00 48 3b 37 75 18 48 89 52 10 48 89 17 eb c3 66 2e 0f 1f 84 00 00 00 00 00 48 89 10 eb b4 <0f> 0b eb fe 0f 1f 80 00 00 00 00 55 48 89 f0 48 89 e5 41 54 49 
RIP  [<ffffffff8129f8d5>] prio_tree_replace+0x75/0x80
 RSP <ffff8873a311bd08>