INFO: task kworker/0:5:5983 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:5 state:D stack:26184 pid:5983 tgid:5983 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: events_power_efficient reg_check_chans_work Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 class_wiphy_constructor include/net/cfg80211.h:6244 [inline] reg_leave_invalid_chans net/wireless/reg.c:2471 [inline] reg_check_chans_work+0x164/0xf30 net/wireless/reg.c:2486 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by kthreadd/2: 3 locks held by kworker/0:0/9: #0: ffff88801a871548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a871548 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900000e7ba0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900000e7ba0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/0:1/10: 3 locks held by kworker/u8:0/12: 3 locks held by kworker/u8:1/13: #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90000127ba0 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90000127ba0 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e1e3f68 (wq_pool_attach_mutex){+.+.}-{4:4}, at: idle_cull_fn+0xca/0x730 kernel/workqueue.c:2960 1 lock held by khungtaskd/31: #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:2/36: 1 lock held by kworker/R-kbloc/39: 4 locks held by kworker/u8:3/50: 3 locks held by kworker/0:1H/56: #0: ffff88801e283148 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801e283148 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000131fba0 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000131fba0 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e3422b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #2: ffffffff8e3422b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957 2 locks held by kworker/u8:4/60: 3 locks held by kworker/u8:5/1038: 3 locks held by kworker/u8:6/1157: 3 locks held by kworker/u8:7/1161: 3 locks held by kworker/R-ipv6_/3201: #0: ffff888030041948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888030041948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000c037b80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000c037b80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4734 3 locks held by kworker/u8:8/3465: 3 locks held by kworker/u8:9/3492: 4 locks held by kworker/u8:10/3605: 1 lock held by klogd/5223: 1 lock held by udevd/5234: 3 locks held by crond/5607: 2 locks held by getty/5626: #0: ffff8880308160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/5852: 1 lock held by syz-executor/5863: #0: ffff88802490a0e0 (&type->s_umount_key#83){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802490a0e0 (&type->s_umount_key#83){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802490a0e0 (&type->s_umount_key#83){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 4 locks held by kworker/1:3/5903: 1 lock held by udevd/5919: #0: ffff888148c0d828 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline] #0: ffff888148c0d828 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:851 3 locks held by kworker/0:3/5942: 3 locks held by kworker/1:7/5957: 2 locks held by kworker/0:4/5964: 4 locks held by kworker/0:5/5983: #0: ffff88801a872948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a872948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000464fba0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000464fba0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x95/0xf30 net/wireless/reg.c:2483 #3: ffff888052058768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6244 [inline] #3: ffff888052058768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_leave_invalid_chans net/wireless/reg.c:2471 [inline] #3: ffff888052058768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_check_chans_work+0x164/0xf30 net/wireless/reg.c:2486 3 locks held by kworker/0:6/5984: 3 locks held by kworker/0:7/5985: 3 locks held by kworker/u8:11/6339: 3 locks held by kworker/u8:12/6340: 3 locks held by syz-executor/7068: 4 locks held by udevd/7075: 1 lock held by kworker/R-wg-cr/7273: #0: ffffffff8e1e3f68 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2736 [inline] #0: ffffffff8e1e3f68 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x88b/0xdd0 kernel/workqueue.c:3556 1 lock held by syz-executor/7334: 3 locks held by kworker/u8:13/7896: 3 locks held by kworker/u8:14/8000: 4 locks held by kworker/u8:15/8002: 3 locks held by kworker/u8:16/8005: 4 locks held by /8085: 1 lock held by kmmpd-loop4/8079: #0: ffff88807bbde420 (sb_writers#4){.+.+}-{0:0}, at: kmmpd+0x391/0xa10 fs/ext4/mmp.c:178 2 locks held by syz.5.325/8106: 2 locks held by dhcpcd-run-hook/8128: 1 lock held by kworker/u8:17/8130: ============================================= 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 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5903 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:check_preemption_disabled+0x3/0x120 lib/smp_processor_id.c:13 Code: 03 8c 48 c7 c6 e0 6e 03 8c eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 53 48 83 ec 10 65 48 8b 05 be 64 40 07 48 89 44 24 08 65 8b RSP: 0018:ffffc90000a07a78 EFLAGS: 00000282 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000101 RDX: ffff8880340a8000 RSI: ffffffff8c036ee0 RDI: ffffffff8c036ea0 RBP: 0000000000000049 R08: 0000000000000000 R09: ffffffff8a647d4e R10: 0000000000000002 R11: ffffffff8a64c9a0 R12: ffff888024521800 R13: ffff888145357f00 R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f17b257b000 CR3: 0000000027a72000 CR4: 00000000003526f0 Call Trace: rcu_lockdep_current_cpu_online+0x37/0x120 kernel/rcu/tree.c:4032 rcu_read_lock_held_common kernel/rcu/update.c:113 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 net_generic+0x101/0x240 include/net/netns/generic.h:46 is_pppoe_ip net/bridge/br_netfilter_hooks.c:122 [inline] br_nf_post_routing+0x4fa/0xfe0 net/bridge/br_netfilter_hooks.c:947 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x215/0x3c0 include/linux/netfilter.h:316 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:-1 [inline] br_nf_forward_finish+0xa40/0xe60 net/bridge/br_netfilter_hooks.c:662 NF_HOOK+0x61b/0x6b0 include/linux/netfilter.h:318 br_nf_forward_ip+0x647/0x7e0 net/bridge/br_netfilter_hooks.c:716 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x215/0x3c0 include/linux/netfilter.h:316 __br_forward+0x41e/0x600 net/bridge/br_forward.c:115 br_handle_frame_finish+0x14b4/0x19b0 net/bridge/br_input.c:221 br_nf_hook_thresh+0x3c6/0x4a0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x999/0xd60 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x37e/0x6b0 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:283 [inline] br_handle_frame+0x982/0x14c0 net/bridge/br_input.c:434 __netif_receive_skb_core+0x10b9/0x4020 net/core/dev.c:5927 __netif_receive_skb_one_core net/core/dev.c:6038 [inline] __netif_receive_skb+0x72/0x380 net/core/dev.c:6153 process_backlog+0x60e/0x14f0 net/core/dev.c:6505 __napi_poll+0xc7/0x360 net/core/dev.c:7555 napi_poll net/core/dev.c:7618 [inline] net_rx_action+0x707/0xe30 net/core/dev.c:7745 handle_softirqs+0x286/0x870 kernel/softirq.c:579 do_softirq+0xec/0x180 kernel/softirq.c:480 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245