======================================
| xx__-> [   21.918881][   T66] ==================================================================
| [ 21.919127][ T66] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [   21.919320][   T66] Read of size 8 at addr ffff88800a2580f8 by task kworker/u16:1/66
| [   21.919506][   T66]
[   21.919788][   T66] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   21.919957][   T66] Workqueue: netns cleanup_net
[   21.920117][   T66] Call Trace:
[   21.920216][   T66]  <TASK>
[ 21.920288][ T66] dump_stack_lvl (lib/dump_stack.c:123)
[ 21.920443][ T66] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 21.920613][ T66] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.920757][ T66] print_report (mm/kasan/report.c:490)
[ 21.920927][ T66] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 21.921071][ T66] kasan_report (mm/kasan/report.c:604)
[ 21.921181][ T66] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.921326][ T66] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.921471][ T66] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 21.921623][ T66] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 21.921780][ T66] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 21.921923][ T66] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 21.922073][ T66] ? process_one_work (kernel/workqueue.c:3205)
[ 21.922223][ T66] process_one_work (kernel/workqueue.c:3229)
[ 21.922370][ T66] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 21.922513][ T66] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 21.922663][ T66] ? assign_work (kernel/workqueue.c:1200)
[ 21.922829][ T66] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 21.922976][ T66] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 21.923158][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 21.923320][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 21.923460][ T66] kthread (kernel/kthread.c:389)
[ 21.923568][ T66] ? __pfx_kthread (kernel/kthread.c:342)
[ 21.923711][ T66] ret_from_fork (arch/x86/kernel/process.c:147)
[ 21.923855][ T66] ? __pfx_kthread (kernel/kthread.c:342)


Finger prints:
print_report:kasan_report:cleanup_net:process_one_work:worker_thread