bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): Released all slaves
==================================================================
BUG: KCSAN: data-race in del_timer / enqueue_timer

write to 0xffff8880aafc5e30 of 8 bytes by task 10 on cpu 1:
 hlist_add_head include/linux/list.h:787 [inline]
 enqueue_timer+0x6c/0x210 kernel/time/timer.c:540
 __internal_add_timer+0x4f/0x60 kernel/time/timer.c:553
 internal_add_timer kernel/time/timer.c:595 [inline]
 __mod_timer kernel/time/timer.c:1053 [inline]
 schedule_timeout+0x2a0/0x6e0 kernel/time/timer.c:1894
 rcu_gp_fqs_loop+0x37c/0x580 kernel/rcu/tree.c:1661
 rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1821
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff8880aafc5e30 of 8 bytes by task 8161 on cpu 0:
 del_timer+0x3b/0xb0 kernel/time/timer.c:1198
 try_to_grab_pending+0x22d/0x3e0 kernel/workqueue.c:1246
 __cancel_work_timer+0x50/0x3a0 kernel/workqueue.c:3087
 cancel_delayed_work_sync+0x24/0x40 kernel/workqueue.c:3260
 batadv_nc_mesh_free+0x4f/0xba net/batman-adv/network-coding.c:1879
 batadv_mesh_free+0x7e/0x120 net/batman-adv/main.c:252
 batadv_softif_free+0x1f/0x30 net/batman-adv/soft-interface.c:1009
 netdev_run_todo+0x3eb/0x580 net/core/dev.c:9579
 rtnl_unlock+0x17/0x20 net/core/rtnetlink.c:112
 default_device_exit_batch+0x239/0x270 net/core/dev.c:10381
 ops_exit_list.isra.0+0xa2/0xc0 net/core/net_namespace.c:175
 cleanup_net+0x405/0x6b0 net/core/net_namespace.c:597
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8161 Comm: kworker/u4:5 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
==================================================================