======================================
| [   31.686884][   T67] ==================================================================
| [ 31.687107][ T67] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [   31.687300][   T67] Read of size 8 at addr ffff888004e000f8 by task kworker/u16:1/67
| [   31.687480][   T67]
[   31.687736][   T67] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   31.687889][   T67] Workqueue: netns cleanup_net
[   31.688022][   T67] Call Trace:
[   31.688122][   T67]  <TASK>
[ 31.688187][ T67] dump_stack_lvl (lib/dump_stack.c:123)
[ 31.688319][ T67] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 31.688476][ T67] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 31.688603][ T67] print_report (mm/kasan/report.c:490)
[ 31.688729][ T67] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 31.688850][ T67] kasan_report (mm/kasan/report.c:604)
[ 31.688946][ T67] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 31.689073][ T67] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 31.689211][ T67] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 31.689341][ T67] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 31.689468][ T67] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 31.689592][ T67] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 31.689714][ T67] ? process_one_work (kernel/workqueue.c:3205)
[ 31.689841][ T67] process_one_work (kernel/workqueue.c:3229)
[ 31.689969][ T67] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 31.690095][ T67] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 31.690223][ T67] ? assign_work (kernel/workqueue.c:1200)
[ 31.690349][ T67] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 31.690471][ T67] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 31.690632][ T67] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 31.690755][ T67] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 31.690877][ T67] kthread (kernel/kthread.c:389)
[ 31.690973][ T67] ? __pfx_kthread (kernel/kthread.c:342)
[ 31.691096][ T67] ret_from_fork (arch/x86/kernel/process.c:147)
[ 31.691217][ T67] ? __pfx_kthread (kernel/kthread.c:342)


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