Comment 62 for bug 1796292

I tried the +3 kernel first, and I got 3 installs and then this hang:

[ 549.828710] bcache: run_cache_set() invalidating existing data
[ 549.836485] bcache: register_cache() registered cache device nvme1n1p2
[ 549.937486] bcache: register_bdev() registered backing device vdg
[ 550.018855] bcache: bch_cached_dev_attach() Caching vdg as bcache3 on set c7abd3ea-f9c9-415a-b8a6-9efeddc3e030
[ 550.074760] bcache: register_bcache() error /dev/vdg: device already registered (emitting change event)
[ 550.316246] bcache: register_bcache() error /dev/vdg: device already registered (emitting change event)
[ 550.545840] bcache: register_bcache() error /dev/vdg: device already registered (emitting change event)
[ 550.565928] bcache: register_bcache() error /dev/vdg: device already registered (emitting change event)
[ 550.724285] bcache: register_bcache() error /dev/vdg: device already registered (emitting change event)
[ 562.352520] md: md0: resync done.
[ 725.980380] INFO: task python3:27303 blocked for more than 120 seconds.
[ 725.982364] Tainted: P O 4.15.0-56-generic #62~lp1796292+3
[ 725.984228] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 725.986284] python3 D 0 27303 27293 0x00000000
[ 725.986287] Call Trace:
[ 725.986319] __schedule+0x291/0x8a0
[ 725.986322] schedule+0x2c/0x80
[ 725.986337] bch_bucket_alloc+0x320/0x3a0 [bcache]
[ 725.986359] ? wait_woken+0x80/0x80
[ 725.986363] __bch_bucket_alloc_set+0xfe/0x150 [bcache]
[ 725.986367] bch_bucket_alloc_set+0x4e/0x70 [bcache]
[ 725.986372] __uuid_write+0x59/0x150 [bcache]
[ 725.986377] ? __write_super+0x137/0x170 [bcache]
[ 725.986382] bch_uuid_write+0x16/0x40 [bcache]
[ 725.986386] __cached_dev_store+0x1d8/0x8a0 [bcache]
[ 725.986391] bch_cached_dev_store+0x39/0xc0 [bcache]
[ 725.986399] sysfs_kf_write+0x3c/0x50
[ 725.986401] kernfs_fop_write+0x125/0x1a0
[ 725.986406] __vfs_write+0x1b/0x40
[ 725.986407] vfs_write+0xb1/0x1a0
[ 725.986409] SyS_write+0x5c/0xe0
[ 725.986416] do_syscall_64+0x73/0x130
[ 725.986419] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 725.986421] RIP: 0033:0x7f2d7c39a154
[ 725.986422] RSP: 002b:00007fff80c5e048 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 725.986426] RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f2d7c39a154
[ 725.986426] RDX: 0000000000000008 RSI: 000000000247e7d0 RDI: 0000000000000003
[ 725.986427] RBP: 00007f2d7c8956c0 R08: 0000000000000000 R09: 0000000000000000
[ 725.986428] R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000000003
[ 725.986428] R13: 0000000000000000 R14: 000000000247e7d0 R15: 00000000021b6e60