======================================
| [  893.851849][   T66] ==================================================================
| [ 893.852193][ T66] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [  893.852464][   T66] Read of size 8 at addr ffff88800f169a38 by task kworker/u16:1/66
| [  893.852665][   T66]
[  893.853006][   T66] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  893.853181][   T66] Workqueue: netns cleanup_net
[  893.853387][   T66] Call Trace:
[  893.853506][   T66]  <TASK>
[ 893.853580][ T66] dump_stack_lvl (lib/dump_stack.c:123)
[ 893.853778][ T66] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 893.854007][ T66] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 893.854150][ T66] print_report (mm/kasan/report.c:490)
[ 893.854305][ T66] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 893.854493][ T66] kasan_report (mm/kasan/report.c:604)
[ 893.854607][ T66] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 893.854764][ T66] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 893.854934][ T66] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 893.855079][ T66] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 893.855233][ T66] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 893.855424][ T66] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 893.855564][ T66] ? process_one_work (kernel/workqueue.c:3205)
[ 893.855702][ T66] process_one_work (kernel/workqueue.c:3229)
[ 893.855846][ T66] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 893.856027][ T66] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 893.856192][ T66] ? assign_work (kernel/workqueue.c:1200)
[ 893.856345][ T66] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 893.856488][ T66] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 893.856711][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 893.856841][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 893.857015][ T66] kthread (kernel/kthread.c:389)
[ 893.857136][ T66] ? __pfx_kthread (kernel/kthread.c:342)
[ 893.857289][ T66] ret_from_fork (arch/x86/kernel/process.c:147)
[ 893.857430][ T66] ? __pfx_kthread (kernel/kthread.c:342)


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