That one completed its first run, but then crashed when bringing CPU 14 back online, with the following dmesg output: [ 163.176945] ------------[ cut here ]------------ [ 163.176949] kernel BUG at /home/jsalisbury/bugs/lp1733662/ubuntu-artful/mm/slub.c:3878! [ 163.178043] invalid opcode: 0000 [#1] SMP [ 163.178995] Modules linked in: nls_iso8859_1 intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass intel_cstate joydev input_leds shpchp ipmi_ssif intel_rapl_perf acpi_power_meter lpc_ich ipmi_si ipmi_devintf ipmi_msghandler acpi_pad mac_hid mei_me mei ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear ses enclosure scsi_transport_sas mgag200 ttm drm_kms_helper crct10dif_pclmul crc32_pclmul ghash_clmulni_intel syscopyarea pcbc sysfillrect fnic aesni_intel hid_generic sysimgblt igb fb_sys_fops aes_x86_64 dca usbhid crypto_simd i2c_algo_bit glue_helper libfcoe hid ahci ptp libfc mxm_wmi cryptd libahci [ 163.186785] drm pps_core enic scsi_transport_fc megaraid_sas wmi [ 163.188025] CPU: 14 PID: 93 Comm: cpuhp/14 Not tainted 4.13.0-13-generic #14~lp1733662Commite6108d5475696 [ 163.189294] Hardware name: Cisco Systems Inc UCSC-C240-M4L/UCSC-C240-M4L, BIOS C240M4.2.0.10c.0.032320160820 03/23/2016 [ 163.190606] task: ffff8dbaf809c5c0 task.stack: ffffae2acc8a8000 [ 163.191926] RIP: 0010:kfree+0x11c/0x160 [ 163.193255] RSP: 0000:ffffae2acc8abb80 EFLAGS: 00010246 [ 163.194600] RAX: fffff9cb3bff0020 RBX: ffff8dba00000000 RCX: ffffae2acc8abb60 [ 163.195954] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000728480000000 [ 163.197311] RBP: ffffae2acc8abb98 R08: ffffae2acc8abaec R09: 0000000000000002 [ 163.198703] R10: fffff9cb3c000000 R11: 0000000000000000 R12: ffff8d9aff94beb0 [ 163.200096] R13: ffffffffa6f2034b R14: ffff8dbaf27e4318 R15: ffff8dbaf27e4200 [ 163.201497] FS: 0000000000000000(0000) GS:ffff8dbaff380000(0000) knlGS:0000000000000000 [ 163.202919] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 163.204351] CR2: 0000000000000000 CR3: 000000101aa09000 CR4: 00000000001406e0 [ 163.205802] Call Trace: [ 163.207253] acpi_ns_get_node_unlocked+0xac/0xd8 [ 163.208704] ? kernfs_add_one+0xe4/0x130 [ 163.210183] ? down_timeout+0x37/0x60 [ 163.211644] ? acpi_os_wait_semaphore+0x4c/0x70 [ 163.213098] acpi_ns_get_node+0x41/0x58 [ 163.214550] ? acpi_ns_get_node+0x41/0x58 [ 163.216016] acpi_get_handle+0x95/0xbe [ 163.217486] acpi_has_method+0x25/0x40 [ 163.218932] acpi_processor_get_performance_info+0x57/0x580 [ 163.220391] ? wrmsrl_on_cpu+0x57/0x70 [ 163.221870] acpi_processor_register_performance+0x5e/0xd0 [ 163.223354] __intel_pstate_cpu_init.part.16+0xed/0x2e0 [ 163.224835] ? intel_pstate_init_cpu+0xc9/0x2d0 [ 163.226323] intel_pstate_cpu_init+0x24/0x40 [ 163.227819] cpufreq_online+0xd8/0x750 [ 163.229301] ? cpufreq_online+0x750/0x750 [ 163.230781] cpuhp_cpufreq_online+0xe/0x20 [ 163.232262] cpuhp_invoke_callback+0x84/0x3b0 [ 163.233758] cpuhp_up_callbacks+0x36/0xc0 [ 163.235254] cpuhp_thread_fun+0xd4/0xe0 [ 163.236731] smpboot_thread_fn+0xec/0x160 [ 163.238210] kthread+0x125/0x140 [ 163.239693] ? sort_range+0x30/0x30 [ 163.241165] ? kthread_create_on_node+0x70/0x70 [ 163.242629] ret_from_fork+0x25/0x30 [ 163.244061] Code: 08 49 83 c4 18 48 89 da 4c 89 ee ff d0 49 8b 04 24 48 85 c0 75 e6 e9 0e ff ff ff 49 8b 02 f6 c4 80 75 0a 49 8b 42 20 a8 01 75 02 <0f> 0b 49 8b 02 31 f6 f6 c4 80 74 04 41 8b 72 6c 4c 89 d7 e8 2c [ 163.247030] RIP: kfree+0x11c/0x160 RSP: ffffae2acc8abb80 [ 163.248463] ---[ end trace e22fa4721cb983b5 ]--- [ 168.454846] ------------[ cut here ]------------ [ 168.456219] kernel BUG at /home/jsalisbury/bugs/lp1733662/ubuntu-artful/mm/slub.c:3878! [ 168.457561] invalid opcode: 0000 [#2] SMP [ 168.458849] Modules linked in: nls_iso8859_1 intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass intel_cstate joydev input_leds shpchp ipmi_ssif intel_rapl_perf acpi_power_meter lpc_ich ipmi_si ipmi_devintf ipmi_msghandler acpi_pad mac_hid mei_me mei ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear ses enclosure scsi_transport_sas mgag200 ttm drm_kms_helper crct10dif_pclmul crc32_pclmul ghash_clmulni_intel syscopyarea pcbc sysfillrect fnic aesni_intel hid_generic sysimgblt igb fb_sys_fops aes_x86_64 dca usbhid crypto_simd i2c_algo_bit glue_helper libfcoe hid ahci ptp libfc mxm_wmi cryptd libahci [ 168.468659] drm pps_core enic scsi_transport_fc megaraid_sas wmi [ 168.470126] CPU: 0 PID: 2683 Comm: irqbalance Tainted: G D 4.13.0-13-generic #14~lp1733662Commite6108d5475696 [ 168.471648] Hardware name: Cisco Systems Inc UCSC-C240-M4L/UCSC-C240-M4L, BIOS C240M4.2.0.10c.0.032320160820 03/23/2016 [ 168.473183] task: ffff8dbae2bf9740 task.stack: ffffae2acf51c000 [ 168.474734] RIP: 0010:kfree+0x11c/0x160 [ 168.476246] RSP: 0018:ffffae2acf51fa08 EFLAGS: 00010246 [ 168.477765] RAX: fffff9cb3bff0020 RBX: ffff8dba00000000 RCX: 0000000000000000 [ 168.479292] RDX: 0000000000000000 RSI: ffff8dbae313ed10 RDI: 0000728480000000 [ 168.480797] RBP: ffffae2acf51fa20 R08: ffff8dbae2a5bac8 R09: 0000000180220021 [ 168.482306] R10: fffff9cb3c000000 R11: 0000000000000001 R12: ffff8dbaf2f60960 [ 168.483831] R13: ffffffffa6bdd4e0 R14: ffff8dbae33fbcd8 R15: ffff8dbae33fae00 [ 168.485365] FS: 00007f342d25a740(0000) GS:ffff8d9affc00000(0000) knlGS:0000000000000000 [ 168.486926] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 168.488478] CR2: 0000560651c9f3a8 CR3: 0000003ff4879000 CR4: 00000000001406f0 [ 168.490066] Call Trace: [ 168.491641] kfree_const+0x20/0x30 [ 168.493227] kernfs_put+0x71/0x180 [ 168.494793] kernfs_dop_release+0x12/0x20 [ 168.496367] __dentry_kill+0xe5/0x150 [ 168.497925] shrink_dentry_list+0x11f/0x2e0 [ 168.499478] d_invalidate+0x67/0x110 [ 168.501018] lookup_fast+0x2b9/0x310 [ 168.502552] ? dput.part.23+0x2d/0x1e0 [ 168.504096] walk_component+0x49/0x340 [ 168.505624] ? kernfs_iop_permission+0x4f/0x60 [ 168.507170] link_path_walk+0x1bc/0x590 [ 168.508703] ? path_init+0x177/0x2f0 [ 168.510248] path_lookupat+0x56/0x1f0 [ 168.511794] filename_lookup+0xb6/0x190 [ 168.513341] ? sprintf+0x51/0x70 [ 168.514885] ? __check_object_size+0xaf/0x1b0 [ 168.516429] ? strncpy_from_user+0x4d/0x170 [ 168.517968] user_path_at_empty+0x36/0x40 [ 168.519514] ? user_path_at_empty+0x36/0x40 [ 168.521020] vfs_statx+0x76/0xe0 [ 168.522481] SYSC_newstat+0x3d/0x70 [ 168.523922] ? ____fput+0xe/0x10 [ 168.525346] ? task_work_run+0x7b/0x90 [ 168.526777] ? exit_to_usermode_loop+0x9b/0xd0 [ 168.528186] SyS_newstat+0xe/0x10 [ 168.529565] entry_SYSCALL_64_fastpath+0x1e/0xa9 [ 168.530924] RIP: 0033:0x7f342c34abb5 [ 168.532229] RSP: 002b:00007ffcd3f64668 EFLAGS: 00000246 ORIG_RAX: 0000000000000004 [ 168.533535] RAX: ffffffffffffffda RBX: 0000000000b95fa0 RCX: 00007f342c34abb5 [ 168.534805] RDX: 00007ffcd3f646c0 RSI: 00007ffcd3f646c0 RDI: 00007ffcd3f65f50 [ 168.536043] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000038 [ 168.537240] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 168.538390] R13: 00007ffcd3f64f6b R14: 0000000000b95fa0 R15: 0000000000b96250 [ 168.539524] Code: 08 49 83 c4 18 48 89 da 4c 89 ee ff d0 49 8b 04 24 48 85 c0 75 e6 e9 0e ff ff ff 49 8b 02 f6 c4 80 75 0a 49 8b 42 20 a8 01 75 02 <0f> 0b 49 8b 02 31 f6 f6 c4 80 74 04 41 8b 72 6c 4c 89 d7 e8 2c [ 168.541855] RIP: kfree+0x11c/0x160 RSP: ffffae2acf51fa08 [ 168.543000] ---[ end trace e22fa4721cb983b6 ]--- The system is semi-responsive; bash continues to run, but most external commands seem to hang. Thus, I've rebooted via the BMC.