Comment 2 for bug 1859582

This can easily be reproduced on another moonshot node with the same 5.0.0-38 kernel (clean deploy with Disco by MAAS)

And issue exists in the proposed 5.0.0-39 kernel as well.

[ OK ] Reached target Final Step.
[ OK ] Started Reboot.
[ OK ] Reached target Reboot.
         Stopping LVM2 metadata daemon...
[ 433.924174] kernel BUG at mm/slub.c:305!
[ 433.971224] Internal error: Oops - BUG: 0 [#1] SMP
[ 434.028703] Modules linked in: dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua gpio_keys_polled input_polldev mailbox_xgene_slimpro crct10dif_ce xgene_rng uio_pdrv_genirq uio sch_fq_codel ib_iser rdma_cm iw_cm ib_cm iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor xor_neon raid6_pq libcrc32c raid1 raid0 multipath linear mlx4_ib ib_uverbs ib_core mlx4_en mlx4_core devlink gpio_dwapb ahci_xgene gpio_xgene_sb
[ 434.598420] Process shutdown (pid: 1, stack limit = 0x00000000024008b6)
[ 434.677705] CPU: 5 PID: 1 Comm: shutdown Not tainted 5.0.0-38-generic #41-Ubuntu
[ 434.766479] Hardware name: HP ProLiant m400 Server Cartridge (DT)
[ 434.839504] pstate: 60400005 (nZCv daif +PAN -UAO)
[ 434.896885] pc : __slab_free+0x170/0x3d8
[ 434.943928] lr : kfree+0x1b4/0x1c8
[ 434.984611] sp : ffff000017c2b950
[ 435.024253] x29: ffff000017c2b950 x28: ffff00001173c708
[ 435.087888] x27: 0000000000000010 x26: ffff7e003ea93020
[ 435.151524] x25: 0000000000000002 x24: ffff800faa4c2c00
[ 435.215159] x23: ffff800ff6003800 x22: 0000000000000000
[ 435.278794] x21: 000000008020000f x20: ffff800faa4c2c00
[ 435.342429] x19: ffff7e003ea93000 x18: 000000000000000c
[ 435.406063] x17: 0000000000000000 x16: 0000000000000000
[ 435.469700] x15: ffff000010fb7f30 x14: ffff800fab1ef390
[ 435.533334] x13: ffff800ff50ec760 x12: 0000000000000000
[ 435.596969] x11: ffff800ff50ec6d8 x10: 0000000000000040
[ 435.660605] x9 : ffff800fab1ef398 x8 : 0000000000000001
[ 435.724240] x7 : ffff800faa4c2c00 x6 : 0000000000000001
[ 435.787875] x5 : 0000000000210d00 x4 : 0000000000000001
[ 435.851510] x3 : ffff800faa4c2c00 x2 : 0000000000000000
[ 435.915146] x1 : 0000000040000000 x0 : 0000000000210d00
[ 435.978781] Call trace:
[ 436.007993] __slab_free+0x170/0x3d8
[ 436.050763] kfree+0x1b4/0x1c8
[ 436.087281] cm_remove_one+0x21c/0x2b0 [ib_cm]
[ 436.140602] ib_unregister_device+0x100/0x218 [ib_core]
[ 436.203300] mlx4_ib_remove+0x84/0x1f8 [mlx4_ib]
[ 436.258703] mlx4_remove_device+0xcc/0xf8 [mlx4_core]
[ 436.319322] mlx4_unregister_device+0x84/0x158 [mlx4_core]
[ 436.385154] mlx4_unload_one+0x88/0x2c8 [mlx4_core]
[ 436.443684] mlx4_shutdown+0x70/0x88 [mlx4_core]
[ 436.499075] pci_device_shutdown+0x44/0x88
[ 436.548208] device_shutdown+0x134/0x240
[ 436.595153] kernel_restart_prepare+0x44/0x50
[ 436.647415] kernel_restart+0x20/0x68
[ 436.691230] __se_sys_reboot+0x10c/0x230
[ 436.738173] __arm64_sys_reboot+0x24/0x30
[ 436.786161] el0_svc_common+0xa0/0x168
[ 436.831018] el0_svc_handler+0x38/0x78
[ 436.875876] el0_svc+0x8/0xc
[ 436.910304] Code: 8b020303 eb14031f 54fff921 d503201f (d4210000)
[ 436.983435] ---[ end trace 5014d8c4f5e4f10d ]---