======================================
| xx__-> [   11.035977][   T63] ==================================================================
| [ 11.036284][ T63] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [   11.036515][   T63] Read of size 8 at addr ffff888009d980f8 by task kworker/u16:1/63
| [   11.036734][   T63]
[   11.037036][   T63] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   11.037218][   T63] Workqueue: netns cleanup_net
[   11.037369][   T63] Call Trace:
[   11.037479][   T63]  <TASK>
[ 11.037561][ T63] dump_stack_lvl (lib/dump_stack.c:123)
[ 11.037721][ T63] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 11.037904][ T63] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 11.038064][ T63] print_report (mm/kasan/report.c:490)
[ 11.038216][ T63] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 11.038366][ T63] kasan_report (mm/kasan/report.c:604)
[ 11.038479][ T63] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 11.038630][ T63] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 11.038843][ T63] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 11.038994][ T63] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 11.039136][ T63] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 11.039287][ T63] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 11.039430][ T63] ? process_one_work (kernel/workqueue.c:3205)
[ 11.039588][ T63] process_one_work (kernel/workqueue.c:3229)
[ 11.039753][ T63] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 11.039901][ T63] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 11.040051][ T63] ? assign_work (kernel/workqueue.c:1200)
[ 11.040201][ T63] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 11.040374][ T63] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 11.040555][ T63] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 11.040705][ T63] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 11.040847][ T63] kthread (kernel/kthread.c:389)
[ 11.040957][ T63] ? __pfx_kthread (kernel/kthread.c:342)
[ 11.041109][ T63] ret_from_fork (arch/x86/kernel/process.c:147)
[ 11.041261][ T63] ? __pfx_kthread (kernel/kthread.c:342)


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