xeon08 login: [  244.741758] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[  244.750940] IP: __cpuhp_state_remove_instance+0xc1/0x1c0
[  244.757246] PGD 80000020390b2067 P4D 80000020390b2067 PUD 2036ad9067 PMD 0
[  244.765445] Oops: 0002 [#1] SMP PTI
[  244.769713] Modules linked in: msr(E) lttng_probe_x86_exceptions(OE) lttng_probe_x86_irq_vectors(OE) lttng_probe_writeback(OE) lttng_probe_workqueue(OE) lttng_probe_vmscan(OE) lttng_probe_udp(OE) lttng_probe_timer(OE) lttng_probe_sunrpc(OE) lttng_probe_statedump(OE) lttng_probe_sock(OE) lttng_probe_skb(OE) lttng_probe_signal(OE) lttng_probe_scsi(OE) lttng_probe_sched(OE) lttng_probe_regmap(OE) lttng_probe_rcu(OE) lttng_probe_random(OE) lttng_probe_printk(OE) lttng_probe_power(OE) lttng_probe_net(OE) lttng_probe_napi(OE) lttng_probe_module(OE) lttng_probe_kvm_x86_mmu(OE) lttng_probe_kvm_x86(OE) kvm(E) irqbypass(E) lttng_probe_kvm(OE) lttng_probe_kmem(OE) lttng_probe_jbd2(OE) lttng_probe_irq(OE) lttng_probe_i2c(OE) lttng_probe_gpio(OE) lttng_probe_ext4(OE) lttng_probe_compaction(OE) lttng_probe_block(OE)
[  244.852692]  lttng_ring_buffer_metadata_mmap_client(OE) lttng_ring_buffer_client_mmap_overwrite(OE) lttng_ring_buffer_client_mmap_discard(OE) lttng_ring_buffer_metadata_client(OE) lttng_ring_buffer_client_overwrite(OE) lttng_ring_buffer_client_discard(OE) lttng_tracer(OE) lttng_statedump(OE) lttng_ftrace(OE) lttng_kprobes(OE) lttng_clock(OE) lttng_lib_ring_buffer(OE) lttng_kretprobes(OE) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) fscache(E) af_packet(E) iscsi_ibft(E) iscsi_boot_sysfs(E) intel_rapl(E) sb_edac(E) x86_pkg_temp_thermal(E) intel_powerclamp(E) mgag200(E) hfi1(E) coretemp(E) drm_kms_helper(E) crct10dif_pclmul(E) syscopyarea(E) crc32_pclmul(E) sysfillrect(E) crc32c_intel(E) sysimgblt(E) fb_sys_fops(E) ttm(E) ixgbe(E) aesni_intel(E) drm(E) rdmavt(E) aes_x86_64(E) mdio(E) iTCO_wdt(E)
[  244.852724]  ipmi_si(E) joydev(E) ptp(E) crypto_simd(E) iTCO_vendor_support(E) i2c_algo_bit(E) ipmi_devintf(E) cryptd(E) pps_core(E) glue_helper(E) mei_me(E) ipmi_msghandler(E) ioatdma(E) pcspkr(E) lpc_ich(E) mei(E) mfd_core(E) i2c_i801(E) dca(E) shpchp(E) wmi(E) acpi_pad(E) ib_ipoib(E) acpi_cpufreq(E) rdma_ucm(E) button(E) ib_ucm(E) ib_uverbs(E) ib_umad(E) rdma_cm(E) configfs(E) ib_cm(E) iw_cm(E) ib_core(E) ext4(E) crc16(E) mbcache(E) jbd2(E) hid_generic(E) usbhid(E) sd_mod(E) xhci_pci(E) xhci_hcd(E) ehci_pci(E) ehci_hcd(E) ahci(E) libahci(E) libata(E) usbcore(E) sg(E) scsi_mod(E) autofs4(E)
[  244.852757] CPU: 36 PID: 2401 Comm: lttng-sessiond Tainted: G           OE    4.15.9-stable #4
[  244.852758] Hardware name: Intel Corporation S2600WTTR/S2600WTTR, BIOS SE5C610.86B.01.01.0016.033120161139 03/31/2016
[  244.852760] RIP: 0010:__cpuhp_state_remove_instance+0xc1/0x1c0
[  244.852761] RSP: 0018:ffffc9000996fa98 EFLAGS: 00010246
[  244.852762] RAX: 0000000000000000 RBX: 0000000000000038 RCX: 0000000000000000
[  244.852763] RDX: 0000000000000000 RSI: 0000000000000038 RDI: ffffffff822fbea0
[  244.852763] RBP: 0000000000000041 R08: 0000000000000000 R09: 0000000000000000
[  244.852764] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88202d29bc68
[  244.852764] R13: 0000000000016aa0 R14: 0000000000000a28 R15: 0000000000000000
[  244.852765] FS:  00007fc00effd700(0000) GS:ffff88103f200000(0000) knlGS:0000000000000000
[  244.852766] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  244.852767] CR2: 0000000000000000 CR3: 0000002038570002 CR4: 00000000003606e0
[  244.852768] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  244.852768] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  244.852769] Call Trace:
[  244.852776]  ? channel_backend_init+0x1dc/0x2f0 [lttng_lib_ring_buffer]
[  244.852780]  channel_backend_init+0x1dc/0x2f0 [lttng_lib_ring_buffer]
[  244.852783]  channel_create+0x6d/0x1b0 [lttng_lib_ring_buffer]
[  244.852788]  _channel_create+0x34/0x80 [lttng_ring_buffer_client_discard]
[  244.852831]  lttng_channel_create+0xff/0x1c0 [lttng_tracer]
[  244.852843]  lttng_abi_create_channel+0x119/0x220 [lttng_tracer]
[  244.852855]  lttng_session_ioctl+0x19e/0x2e0 [lttng_tracer]
[  244.852859]  ? hrtimer_try_to_cancel+0xc4/0x110
[  244.852862]  ? hrtimer_try_to_cancel+0xc4/0x110
[  244.852864]  ? hrtimer_cancel+0x15/0x20
[  244.852867]  ? futex_wait+0x177/0x220
[  244.852872]  ? sched_clock+0x5/0x10
[  244.852875]  ? sched_clock_cpu+0xc/0xa0
[  244.852877]  ? __lock_acquire.isra.31+0x165/0x700
[  244.852886]  do_vfs_ioctl+0x8f/0x5e0
[  244.852890]  ? __fget+0xb4/0xf0
[  244.852891]  ? __fget+0x5/0xf0
[  244.852893]  SyS_ioctl+0x74/0x80
[  244.852898]  do_syscall_64+0x6e/0x1a0
[  244.852901]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[  244.852902] RIP: 0033:0x7fc0154254b7
[  244.852903] RSP: 002b:00007fc00efec5b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[  244.852904] RAX: ffffffffffffffda RBX: 00007fc000005410 RCX: 00007fc0154254b7
[  244.852905] RDX: 00007fc00efec5c0 RSI: 000000004140f655 RDI: 0000000000000030
[  244.852905] RBP: 00007fc000005470 R08: 0000000000000000 R09: 0000000000000030
[  244.852906] R10: fffffffffffffe80 R11: 0000000000000246 R12: 00000000ffffffff
[  244.852907] R13: 00007fc000001b70 R14: 0000000000000050 R15: 00007fc000001b70
[  244.852910] Code: 15 25 b8 fd 00 85 d2 0f 85 f9 00 00 00 31 f6 48 c7 c7 00 b8 05 82 e8 8f c0 63 00 84 db 75 75 49 8b 04 24 49 8b 54 24 08 48 85 c0 <48> 89 02 74 04 48 89 50 08 48 b8 00 01 00 00 00 00 ad de 48 c7
[  244.852934] RIP: __cpuhp_state_remove_instance+0xc1/0x1c0 RSP: ffffc9000996fa98
[  244.852935] CR2: 0000000000000000
[  244.852937] ---[ end trace a8be70506d9817e6 ]---