I noticed this from rawhide composes. The Cloud Base compose failed and it seems the boot never finishes with these kernels. 

The x86_64 one has a screenshot: https://koji.fedoraproject.org/koji/taskinfo?taskID=37916159

I captured some console messages on aarch64: 

B Keyboard] on usb-0000:02:00.0-2/input0
[   40.056886] watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:12]
[   40.058373] Modules linked in:
[   40.058994] irq event stamp: 32947716
[   40.059737] hardirqs last  enabled at (32947715): [<ffffa40c1771a74c>] _raw_write_unlock_irqrest
ore+0x74/0xa0
[   40.061709] hardirqs last disabled at (32947716): [<ffffa40c16a53734>] el1_irq+0xb4/0x1c0
[   40.063327] softirqs last  enabled at (32935094): [<ffffa40c16a51e80>] __do_softirq+0x480/0x57c
[   40.065048] softirqs last disabled at (32935087): [<ffffa40c16ade59c>] irq_exit+0x11c/0x148
[   40.066708] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.4.0-0.rc0.git7.1.fc32.aarch64 #1
[   40.068370] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[   40.069753] Workqueue: events kmemleak_do_cleanup
[   40.070701] pstate: 60400005 (nZCv daif +PAN -UAO)
[   40.071654] pc : _raw_write_unlock_irqrestore+0x78/0xa0
[   40.072704] lr : _raw_write_unlock_irqrestore+0x74/0xa0
[   40.073747] sp : ffff800010073cb0
[   40.074415] x29: ffff800010073cb0 x28: ffffa40c1851ded8 
[   40.075479] x27: ffffa40c18331000 x26: 0000000000000000 
[   40.076542] x25: ffffa40c18331278 x24: 0000000000000000 
[   40.077631] x23: ffff0000c1173c00 x22: 0000000000000000 
[   40.078699] x21: ffffa40c16d8a4ec x20: ffffa40c18394d58 
[   40.079755] x19: 0000000000000000 x18: 0000000000000014 
[   40.080818] x17: 000000005c0a3c18 x16: 00000000ff323a58 
[   40.081880] x15: 0000000041d580da x14: 0000000059bc1e33 
[   40.082951] x13: 00000000560cec5e x12: ffffffffffffffff 
[   40.084016] x11: 0000000000000040 x10: 0101010101010101 
[   40.085080] x9 : 0000000000000002 x8 : ffffa40c18394d70 
[   40.086148] x7 : ffffa40c16d8a490 x6 : 0000000000000000 
[   40.087209] x5 : ffff800010073c58 x4 : 0000000000000003 
[   40.088288] x3 : 0000000000000002 x2 : 0000000000000007 
[   40.089353] x1 : ffff0000c0168918 x0 : ffff0000c0168000 
[   40.090420] Call trace:
[   40.090919]  _raw_write_unlock_irqrestore+0x78/0xa0
[   40.091899]  find_and_remove_object+0x8c/0xa0
[   40.092777]  delete_object_full+0x24/0x38
[   40.093585]  __kmemleak_do_cleanup+0x88/0x148
[   40.094461]  kmemleak_do_cleanup+0x60/0x80
[   40.095287]  process_one_work+0x278/0x6b0
[   40.096093]  worker_thread+0x50/0x408
[   40.096835]  kthread+0x108/0x138
[   40.097504]  ret_from_fork+0x10/0x18
[   60.696908] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 46s!
[   60.698436] Showing busy workqueues and worker pools:
[   60.699373] workqueue events: flags=0x0
[   60.700107]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256
[   60.701279]     in-flight: 12:kmemleak_do_cleanup
[   60.702135]     pending: psi_avgs_work, vmstat_shepherd
[   60.703100] workqueue mm_percpu_wq: flags=0x8
[   60.703888]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[   60.704965]     pending: vmstat_update
[   60.705664] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=46s workers=2 idle: 5
[   78.986882] rcu: INFO: rcu_sched self-detected stall on CPU
[   78.988070] rcu:     0-....: (6495 ticks this GP) idle=252/1/0x4000000000000002 softirq=974/974 
fqs=3246 
[   78.989992]  (t=6500 jiffies g=505 q=318)
[   78.990822] Task dump for CPU 0:
[   78.991471] kworker/0:1     R  running task    13968    12      2 0x0000002a
[   78.992889] Workqueue: events kmemleak_do_cleanup
[   78.993829] Call trace:
[   78.994324]  dump_backtrace+0x0/0x148
[   78.995053]  show_stack+0x24/0x30
[   78.995716]  sched_show_task+0x224/0x250
[   78.996505]  dump_cpu_task+0x48/0x58
[   78.997227]  rcu_dump_cpu_stacks+0xa4/0xe4
[   78.998044]  check_cpu_stall.isra.0+0x4a8/0x670
[   78.998943]  rcu_sched_clock_irq+0xdc/0x438
[   78.999778]  update_process_times+0x34/0x70
[   79.000606]  tick_sched_handle.isra.0+0x34/0x70
[   79.001525]  tick_sched_timer+0x50/0xa0
[   79.002293]  __run_hrtimer+0x12c/0x560
[   79.003043]  __hrtimer_run_queues+0x80/0xe0
[   79.003875]  hrtimer_interrupt+0xec/0x248
[   79.004672]  arch_timer_handler_virt+0x3c/0x50
[   79.005556]  handle_percpu_devid_irq+0xe4/0x438
[   79.006464]  generic_handle_irq+0x34/0x50
[   79.007262]  __handle_domain_irq+0x6c/0xc0
[   79.008074]  gic_handle_irq+0x58/0xa8
[   79.008805]  el1_irq+0xf4/0x1c0
[   79.009434]  _raw_write_unlock_irqrestore+0x78/0xa0
[   79.010400]  find_and_remove_object+0x8c/0xa0
[   79.011277]  delete_object_full+0x24/0x38
[   79.012074]  __kmemleak_do_cleanup+0x88/0x148
[   79.012937]  kmemleak_do_cleanup+0x60/0x80
[   79.013749]  process_one_work+0x278/0x6b0
[   79.014550]  worker_thread+0x50/0x408
[   79.015278]  kthread+0x108/0x138
[   79.015932]  ret_from_fork+0x10/0x18
[  104.056878] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kworker/0:1:12]
[  104.058568] Modules linked in:
[  104.059308] irq event stamp: 113632378
[  104.060196] hardirqs last  enabled at (113632377): [<ffffa40c1771a74c>] _raw_write_unlock_irqres
tore+0x74/0xa0
[  104.062509] hardirqs last disabled at (113632378): [<ffffa40c16a53734>] el1_irq+0xb4/0x1c0
[  104.064557] softirqs last  enabled at (58956150): [<ffffa40c16a51e80>] __do_softirq+0x480/0x57c
[  104.066739] softirqs last disabled at (58956077): [<ffffa40c16ade59c>] irq_exit+0x11c/0x148
[  104.068852] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G             L    5.4.0-0.rc0.git7.1.fc32
.aarch64 #1
[  104.071292] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[  104.073074] Workqueue: events kmemleak_do_cleanup
[  104.074232] pstate: 60400005 (nZCv daif +PAN -UAO)
[  104.075464] pc : _raw_write_unlock_irqrestore+0x78/0xa0
[  104.076771] lr : _raw_write_unlock_irqrestore+0x74/0xa0
[  104.078041] sp : ffff800010073cb0
[  104.078869] x29: ffff800010073cb0 x28: ffffa40c1851ded8 
[  104.080203] x27: ffffa40c18331000 x26: 0000000000000000 
[  104.081524] x25: ffffa40c18331278 x24: 0000000000000000 
[  104.082890] x23: ffff0000c1173c00 x22: 0000000000000000 
[  104.084225] x21: ffffa40c16d8a4ec x20: ffffa40c18394d58 
[  104.085549] x19: 0000000000000000 x18: 0000000000000014 
[  104.086859] x17: 000000005c0a3c18 x16: 00000000ff323a58 
[  104.088141] x15: 0000000041d580da x14: 0000000059bc1e33 
[  104.089456] x13: 00000000560cec5e x12: ffffffffffffffff 
[  104.090765] x11: 0000000000000040 x10: 0101010101010101 
[  104.092101] x9 : 0000000000000002 x8 : ffffa40c18394d70 
[  104.093433] x7 : ffffa40c16d8a490 x6 : 0000000000000000 
[  104.094676] x5 : ffff800010073c58 x4 : 0000000000000003 
[  104.095914] x3 : 0000000000000002 x2 : 0000000000000007 
[  104.097147] x1 : ffff0000c0168918 x0 : ffff0000c0168000 
[  104.098384] Call trace:
[  104.098978]  _raw_write_unlock_irqrestore+0x78/0xa0
[  104.100126]  find_and_remove_object+0x8c/0xa0
[  104.101163]  delete_object_full+0x24/0x38
[  104.102105]  __kmemleak_do_cleanup+0x88/0x148
[  104.103157]  kmemleak_do_cleanup+0x60/0x80
[  104.104130]  process_one_work+0x278/0x6b0
[  104.105084]  worker_thread+0x50/0x408
[  104.105956]  kthread+0x108/0x138
[  104.106733]  ret_from_fork+0x10/0x18

Also, it fails to boot on my laptop. I can get a screenshot if it helps. 

I suspect this won't be too hard to duplicate. :) 

If so, happy to provide more info...