INFO: task kworker/u8:4:63 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:23584 pid:63    tgid:63    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
 linkwatch_event+0xe/0x60 net/core/link_watch.c:313
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.3.6496:18929 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.6496      state:D stack:27696 pid:18929 tgid:18925 ppid:6570   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
 rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 inet_rtm_newroute+0x12b/0x250 net/ipv4/fib_frontend.c:922
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f087819c799
RSP: 002b:00007f0878faa028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0878415fa0 RCX: 00007f087819c799
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007f0878232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0878416038 R14: 00007f0878415fa0 R15: 00007f087853fa48
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/0:0/9:
3 locks held by kworker/0:1/10:
2 locks held by kworker/u8:0/12:
1 lock held by kworker/R-mm_pe/14:
3 locks held by kworker/1:1/29:
1 lock held by khungtaskd/31:
 #0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by kworker/R-write/33:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2749 [inline]
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0xc4d/0x1130 kernel/workqueue.c:3611
3 locks held by kworker/u8:2/36:
3 locks held by kworker/u8:3/49:
3 locks held by kworker/u8:4/63:
 #0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000212fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000212fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
3 locks held by kworker/u8:5/106:
3 locks held by kworker/1:2/795:
 #0: ffff88813fe0dd48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88813fe0dd48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90004217c40 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90004217c40 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0xa5/0xfe0 net/wireless/reg.c:2462
3 locks held by kworker/u8:7/1034:
3 locks held by kworker/u8:8/1156:
3 locks held by kworker/1:3/1551:
3 locks held by kworker/R-ipv6_/3184:
 #0: ffff88803192e948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88803192e948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000d25fc00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000d25fc00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4738
4 locks held by kworker/R-bat_e/3409:
3 locks held by kworker/u8:9/3561:
1 lock held by kworker/R-ext4-/5157:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
1 lock held by klogd/5183:
1 lock held by dhcpcd/5490:
2 locks held by getty/5583:
 #0: ffff888036de10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5807:
4 locks held by kworker/0:3/5834:
 #0: ffff888067bb6148 ((wq_completion)wg-kex-wg2#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888067bb6148 ((wq_completion)wg-kex-wg2#2){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90003ca7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90003ca7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffff88806d5e5348 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x1a1/0x9a0 drivers/net/wireguard/noise.c:598
 #3: ffff88802b642ad8 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x630/0x9a0 drivers/net/wireguard/noise.c:643
5 locks held by syz-executor/6568:
5 locks held by syz-executor/6569:
1 lock held by kworker/R-wg-cr/6597:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
4 locks held by kworker/1:4/6600:
1 lock held by kworker/R-wg-cr/6601:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
1 lock held by kworker/R-wg-cr/6603:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
3 locks held by kworker/1:5/6694:
3 locks held by kworker/1:7/6733:
1 lock held by kworker/R-bond1/12060:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
4 locks held by kworker/u8:1/18651:
1 lock held by kworker/R-bond3/18878:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
6 locks held by syz.4.6488/18912:
4 locks held by syz.1.6491/18917:
1 lock held by syz.3.6496/18929:
 #0: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8fbcd988 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newroute+0x12b/0x250 net/ipv4/fib_frontend.c:922
4 locks held by kworker/u8:6/18932:
3 locks held by kworker/u8:10/18933:
1 lock held by kworker/u8:11/18934:
 #0: ffffffff8e5fcde8 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2691
4 locks held by kworker/0:2/18935:
 #0: ffff888043d17d48 ((wq_completion)wg-kex-wg1#10){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888043d17d48 ((wq_completion)wg-kex-wg1#10){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90003b57c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90003b57c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffff888064e59348 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x1a1/0x9a0 drivers/net/wireguard/noise.c:598
 #3: ffff88802ab11708 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x58b/0x9a0 drivers/net/wireguard/noise.c:632

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3409 Comm: kworker/R-bat_e Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: bat_events batadv_tt_purge
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:lockdep_hardirqs_off+0x2f/0xd0 kernel/locking/lockdep.c:4502
Code: 56 53 83 3d d2 89 63 04 00 0f 84 84 00 00 00 48 89 fb 65 8b 05 32 bc 6d 07 a9 00 00 f0 00 74 5c 83 3d 74 20 79 0e 00 75 09 9c <58> a9 00 02 00 00 75 6a 65 8b 05 1a fe 6d 07 85 c0 74 56 65 4c 8b
RSP: 0018:ffffc90000a07fc8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff8bb0de5a RCX: 0000000080000101
RDX: ffffea0002aafd80 RSI: ffffffff8df5b9ab RDI: ffffffff8c27be00
RBP: 0000000000a12110 R08: ffff88803256bd00 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000100 R12: ffff8880aabf6370
R13: ffff8880aabf6280 R14: ffffffff9a54f3d0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125560000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9fe3ffffc CR3: 000000007f9be000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 trace_hardirqs_off+0x12/0x40 kernel/trace/trace_preemptirq.c:104
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
 _raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:162
 __debug_check_no_obj_freed lib/debugobjects.c:1105 [inline]
 debug_check_no_obj_freed+0x145/0x550 lib/debugobjects.c:1146
 slab_free_hook mm/slub.c:2616 [inline]
 slab_free mm/slub.c:6165 [inline]
 kmem_cache_free+0x100/0x630 mm/slub.c:6295
 netlink_broadcast_filtered+0xee4/0x1020 net/netlink/af_netlink.c:1535
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
 br_fdb_update+0x4c8/0x690 net/bridge/br_fdb.c:1040
 br_handle_frame_finish+0x573/0x1bb0 net/bridge/br_input.c:144
 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
 br_nf_pre_routing_finish_ipv6+0xa3a/0xd70 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_nf_pre_routing_ipv6+0x374/0x6f0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
 br_handle_frame+0x1277/0x1510 net/bridge/br_input.c:442
 __netif_receive_skb_core+0x98f/0x31a0 net/core/dev.c:6051
 __netif_receive_skb_one_core net/core/dev.c:6162 [inline]
 __netif_receive_skb net/core/dev.c:6277 [inline]
 process_backlog+0x76d/0x1950 net/core/dev.c:6628
 __napi_poll+0xae/0x340 net/core/dev.c:7692
 napi_poll net/core/dev.c:7755 [inline]
 net_rx_action+0x627/0xf70 net/core/dev.c:7912
 handle_softirqs+0x22a/0x870 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 spin_unlock_bh include/linux/spinlock.h:395 [inline]
 batadv_tt_local_purge+0x2a7/0x340 net/batman-adv/translation-table.c:1315
 batadv_tt_purge+0x35/0x9e0 net/batman-adv/translation-table.c:3509
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 rescuer_thread+0x827/0x1130 kernel/workqueue.c:3583
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>