======================================
| [   59.712974][  T303] ==================================================================
| [ 59.713293][ T303] BUG: KASAN: slab-use-after-free in cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
| [   59.713556][  T303] Read of size 8 at addr ffff88800b3c00f8 by task kworker/u16:2/303
| [   59.713830][  T303]
[   59.714363][  T303] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   59.714636][  T303] Workqueue: netns cleanup_net
[   59.714854][  T303] Call Trace:
[   59.715017][  T303]  <TASK>
[ 59.715140][ T303] dump_stack_lvl (lib/dump_stack.c:123)
[ 59.715365][ T303] print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 59.715629][ T303] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 59.715846][ T303] print_report (mm/kasan/report.c:490)
[ 59.716056][ T303] ? kasan_addr_to_slab (./include/linux/mm.h:1294 mm/kasan/../slab.h:211 mm/kasan/common.c:38)
[ 59.716268][ T303] kasan_report (mm/kasan/report.c:604)
[ 59.716424][ T303] ? cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 59.716629][ T303] cleanup_net (net/core/net_namespace.c:462 net/core/net_namespace.c:661)
[ 59.716839][ T303] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 59.717055][ T303] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 59.717268][ T303] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 47))
[ 59.717488][ T303] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 59.717701][ T303] ? process_one_work (kernel/workqueue.c:3205)
[ 59.717918][ T303] process_one_work (kernel/workqueue.c:3229)
[ 59.718133][ T303] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 59.718336][ T303] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 59.718546][ T303] ? assign_work (kernel/workqueue.c:1200)
[ 59.718757][ T303] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 59.718975][ T303] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 59.719237][ T303] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 59.719444][ T303] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 59.719652][ T303] kthread (kernel/kthread.c:389)
[ 59.719812][ T303] ? __pfx_kthread (kernel/kthread.c:342)
[ 59.720017][ T303] ret_from_fork (arch/x86/kernel/process.c:147)
[ 59.720227][ T303] ? __pfx_kthread (kernel/kthread.c:342)


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