Joseph,

The first run of your latest kernel completed; however, I noticed the following in the dmesg output:

[  426.281083] ==================================================================
[  426.286615] BUG: KASAN: use-after-free in find_first_bit+0x1f/0x80
[  426.291841] Read of size 8 at addr ffff883ff7c1e780 by task cpuhp/31/195

[  426.302209] CPU: 31 PID: 195 Comm: cpuhp/31 Not tainted 4.13.0-25-generic #29~lp1733662KASANenabled
[  426.302213] Hardware name: Cisco Systems Inc UCSC-C240-M4L/UCSC-C240-M4L, BIOS C240M4.2.0.10c.0.032320160820 03/23/2016
[  426.302215] Call Trace:
[  426.302233]  dump_stack+0xb8/0x12d
[  426.302241]  ? dma_virt_map_sg+0xd3/0xd3
[  426.302252]  ? show_regs_print_info+0x41/0x41
[  426.302263]  print_address_description+0x6f/0x280
[  426.302269]  kasan_report+0x27a/0x370
[  426.302276]  ? find_first_bit+0x1f/0x80
[  426.302288]  __asan_load8+0x54/0x90
[  426.302295]  find_first_bit+0x1f/0x80
[  426.302306]  has_busy_rmid+0x47/0x70
[  426.302314]  intel_rdt_offline_cpu+0x4b4/0x510
[  426.302321]  ? clear_closid_rmid.isra.4+0x70/0x70
[  426.302333]  ? sysfs_remove_group+0x7a/0xc0
[  426.302339]  ? clear_closid_rmid.isra.4+0x70/0x70
[  426.302351]  cpuhp_invoke_callback+0x15f/0x7e0
[  426.302360]  ? cpuhp_kick_ap_work+0x2d0/0x2d0
[  426.302372]  ? __schedule+0x4f1/0xeb0
[  426.302377]  ? cpuhp_kick_ap_work+0x2d0/0x2d0
[  426.302385]  ? firmware_map_remove+0x1b1/0x1b1
[  426.302395]  ? migrate_swap_stop+0x2f0/0x2f0
[  426.302402]  ? firmware_map_remove+0x1b1/0x1b1
[  426.302407]  ? migrate_swap_stop+0x2f0/0x2f0
[  426.302414]  ? schedule+0xd8/0x2a0
[  426.302421]  ? __schedule+0xeb0/0xeb0
[  426.302427]  ? default_wake_function+0x2f/0x40
[  426.302439]  ? __wake_up_common+0xa1/0xc0
[  426.302446]  cpuhp_down_callbacks+0x52/0xa0
[  426.302453]  cpuhp_thread_fun+0x117/0x1a0
[  426.302459]  ? cpu_up+0x20/0x20
[  426.302468]  smpboot_thread_fn+0x20e/0x2f0
[  426.302474]  ? sort_range+0x30/0x30
[  426.302482]  kthread+0x1b7/0x1e0
[  426.302488]  ? sort_range+0x30/0x30
[  426.302493]  ? kthread_create_on_node+0xc0/0xc0
[  426.302500]  ret_from_fork+0x1f/0x30

[  426.307683] Allocated by task 56:
[  426.312817]  save_stack_trace+0x1b/0x20
[  426.312824]  save_stack+0x43/0xd0
[  426.312829]  kasan_kmalloc+0xad/0xe0
[  426.312834]  __kmalloc+0x105/0x230
[  426.312840]  intel_rdt_online_cpu+0x5a8/0x830
[  426.312846]  cpuhp_invoke_callback+0x15f/0x7e0
[  426.312850]  cpuhp_thread_fun+0x8b/0x1a0
[  426.312856]  smpboot_thread_fn+0x20e/0x2f0
[  426.312861]  kthread+0x1b7/0x1e0
[  426.312866]  ret_from_fork+0x1f/0x30

[  426.317887] Freed by task 195:
[  426.322879]  save_stack_trace+0x1b/0x20
[  426.322887]  save_stack+0x43/0xd0
[  426.322891]  kasan_slab_free+0x72/0xc0
[  426.322896]  kfree+0x94/0x1a0
[  426.322902]  intel_rdt_offline_cpu+0x17d/0x510
[  426.322908]  cpuhp_invoke_callback+0x15f/0x7e0
[  426.322912]  cpuhp_down_callbacks+0x52/0xa0
[  426.322917]  cpuhp_thread_fun+0x117/0x1a0
[  426.322925]  smpboot_thread_fn+0x20e/0x2f0
[  426.322929]  kthread+0x1b7/0x1e0
[  426.322935]  ret_from_fork+0x1f/0x30

[  426.327837] The buggy address belongs to the object at ffff883ff7c1e780
                which belongs to the cache kmalloc-8 of size 8
[  426.338289] The buggy address is located 0 bytes inside of
                8-byte region [ffff883ff7c1e780, ffff883ff7c1e788)
[  426.348805] The buggy address belongs to the page:
[  426.354223] page:ffffea00ffdf0780 count:1 mapcount:0 mapping:          (null) index:0x0
[  426.359838] flags: 0x57ffffc0000100(slab)
[  426.365373] raw: 0057ffffc0000100 0000000000000000 0000000000000000 0000000100aa00aa
[  426.371135] raw: dead000000000100 dead000000000200 ffff8817f500fb80 0000000000000000
[  426.377004] page dumped because: kasan: bad access detected

[  426.388626] Memory state around the buggy address:
[  426.394498]  ffff883ff7c1e680: fc fc 00 fc fc fb fc fc 00 fc fc fb fc fc 00 fc
[  426.400634]  ffff883ff7c1e700: fc 00 fc fc fb fc fc 00 fc fc fb fc fc fb fc fc
[  426.406721] >ffff883ff7c1e780: fb fc fc fb fc fc fb fc fc 00 fc fc fb fc fc fb
[  426.412737]                    ^
[  426.418698]  ffff883ff7c1e800: fc fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc
[  426.424961]  ffff883ff7c1e880: fc 00 fc fc fb fc fc fb fc fc fb fc fc fb fc fc
[  426.431154] ==================================================================
[  426.437413] Disabling lock debugging due to kernel taint
[  426.472795] IRQ 8: no longer affine to CPU31
[  426.472806] IRQ 9: no longer affine to CPU31
[  426.472827] IRQ 40: no longer affine to CPU31
[  426.473962] smpboot: CPU 31 is now offline

I ran it several more times without any obvious errors; however, I might have missed something. (The dmesg output is quite verbose and scrolls by quickly!)