INFO: task syz-executor:18672 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22584 pid:18672 tgid:18672 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7339 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820 del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffaeb75d60e RSP: 002b:00007ffc62d9e6f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555595420500 RCX: 00007ffaeb75d60e RDX: 0000000000000001 RSI: 00007ffc62d9e780 RDI: 0000000000000005 RBP: 00007ffaeb8335ec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc62d9e780 R14: 00007ffaec544620 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by kworker/R-mm_pe/14: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2717 1 lock held by khungtaskd/30: #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/1:1/46: 3 locks held by kworker/u8:3/48: #0: ffff888031d57940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff888031d57940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90000b87c40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90000b87c40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4746 4 locks held by kworker/u8:6/185: #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90002557c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90002557c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdbfe08 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673 #3: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: wg_destruct+0x25/0x310 drivers/net/wireguard/device.c:246 2 locks held by getty/5381: #0: ffff888035f670a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211 1 lock held by kworker/1:3/5631: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2717 2 locks held by kworker/1:6/5761: 3 locks held by kworker/u8:13/7518: #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90003287c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90003287c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 1 lock held by kworker/R-wg-cr/18364: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2775 [inline] #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0xc4d/0x1130 kernel/workqueue.c:3637 1 lock held by kworker/R-wg-cr/18368: 1 lock held by kworker/R-wg-cr/18369: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2717 1 lock held by kworker/R-wg-cr/18370: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2717 1 lock held by kworker/R-wg-cr/18371: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2775 [inline] #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0xc4d/0x1130 kernel/workqueue.c:3637 1 lock held by kworker/R-wg-cr/18373: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2775 [inline] #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0xc4d/0x1130 kernel/workqueue.c:3637 1 lock held by kworker/R-wg-cr/18374: #0: ffffffff8e7fb000 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2717 3 locks held by kworker/0:10/18400: #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90004ed7c40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90004ed7c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 4 locks held by kworker/1:4/18491: 7 locks held by syz-executor/18617: #0: ffff88803391a410 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff88803391a410 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88806aba8480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff8880296065a8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880296065a8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f64e7a0 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff88802b407128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88802b407128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff88802b407128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x870 drivers/base/dd.c:1372 #5: ffff88802b402258 (&devlink->lock_key#8){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1799 #6: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: unregister_nexthop_notifier+0x17/0x40 net/ipv4/nexthop.c:4021 4 locks held by syz-executor/18672: #0: ffff88803391a410 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff88803391a410 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88802aa91c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff8880296065a8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880296065a8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f64e7a0 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 2 locks held by syz-executor/18869: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438 #1: ffffffff8e7eb750 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:6576 [inline] #1: ffffffff8e7eb750 (cpu_hotplug_lock){++++}-{0:0}, at: unregister_netdevice_many_notify+0xc7f/0x22c0 net/core/dev.c:12397 1 lock held by syz-executor/18919: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438 1 lock held by syz-executor/19007: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4108 1 lock held by syz-executor/19014: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4108 1 lock held by syz-executor/19086: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/19100: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/19108: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/19113: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/19118: #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: 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:162 [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:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 18491 Comm: kworker/1:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:check_preemption_disabled+0x1/0xe0 lib/smp_processor_id.c:13 Code: 00 aa 28 8c 48 c7 c6 40 aa 28 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 65 8b 05 b7 bf 90 07 65 8b 0d ac bf 90 07 f7 c1 ff RSP: 0018:ffffc90000a08460 EFLAGS: 00000283 RAX: 0000000000000001 RBX: ffffffff90d2cf01 RCX: 0000000080000102 RDX: ffffc90000a08601 RSI: ffffffff8c28aa40 RDI: ffffffff8c28aa00 RBP: dffffc0000000000 R08: ffffc90000a08958 R09: 0000000000000000 R10: ffffc90000a08618 R11: fffff520001410c5 R12: ffffc90000a08968 R13: ffffffff8176e256 R14: ffffffff8e95cd60 R15: ffffffff8176e256 FS: 0000000000000000(0000) GS:ffff888125393000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fba55027286 CR3: 000000000e74a000 CR4: 00000000003526f0 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:752 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x4b/0x3c0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4950 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 skb_copy+0x188/0x800 net/core/skbuff.c:2182 can_can_gw_rcv+0x46d/0xf70 net/can/gw.c:507 deliver net/can/af_can.c:575 [inline] can_rcv_filter+0x126/0x7a0 net/can/af_can.c:602 can_receive+0x2c6/0x440 net/can/af_can.c:674 can_rcv+0x1f9/0x330 net/can/af_can.c:699 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0xc66/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7730 napi_poll net/core/dev.c:7793 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7950 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] neigh_periodic_work+0xc28/0xe50 net/core/neighbour.c:1038 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245