======================================
| [   21.742741][   T67] ==================================================================
| [ 21.742963][ T67] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [   21.743153][   T67] Read of size 8 at addr ffff88800bc380f8 by task kworker/u16:1/67
| [   21.743336][   T67]
[   21.743621][   T67] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   21.743776][   T67] Workqueue: netns cleanup_net
[   21.743907][   T67] Call Trace:
[   21.744002][   T67]  <TASK>
[ 21.744072][ T67] dump_stack_lvl (lib/dump_stack.c:123)
[ 21.744206][ T67] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 21.744363][ T67] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.744496][ T67] print_report (mm/kasan/report.c:490)
[ 21.744620][ T67] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 21.744742][ T67] kasan_report (mm/kasan/report.c:604)
[ 21.744834][ T67] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.744959][ T67] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 21.745081][ T67] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 21.745212][ T67] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 21.745339][ T67] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 21.745464][ T67] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 21.745586][ T67] ? process_one_work (kernel/workqueue.c:3205)
[ 21.745712][ T67] process_one_work (kernel/workqueue.c:3229)
[ 21.745834][ T67] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 21.745957][ T67] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 21.746079][ T67] ? assign_work (kernel/workqueue.c:1200)
[ 21.746205][ T67] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 21.746325][ T67] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 21.746477][ T67] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 21.746599][ T67] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 21.746719][ T67] kthread (kernel/kthread.c:389)
[ 21.746814][ T67] ? __pfx_kthread (kernel/kthread.c:342)
[ 21.746938][ T67] ret_from_fork (arch/x86/kernel/process.c:147)
[ 21.747065][ T67] ? __pfx_kthread (kernel/kthread.c:342)


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