INFO: task kworker/u8:10:1026 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:10 state:D stack:21288 pid:1026 tgid:1026 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 io_schedule+0x80/0xe0 kernel/sched/core.c:8154 TXN_SLEEP_DROP_LOCK fs/jfs/jfs_txnmgr.c:125 [inline] txBegin+0x281/0xbe0 fs/jfs/jfs_txnmgr.c:376 jfs_commit_inode+0x1b3/0x530 fs/jfs/inode.c:107 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138 write_inode fs/fs-writeback.c:1607 [inline] __writeback_single_inode+0x6af/0xf90 fs/fs-writeback.c:1850 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2079 wb_writeback+0x41c/0xad0 fs/fs-writeback.c:2264 wb_do_writeback fs/fs-writeback.c:2432 [inline] wb_workfn+0x437/0x10f0 fs/fs-writeback.c:2477 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 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 INFO: task syz-executor:12502 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:22456 pid:12502 tgid:12502 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 wb_wait_for_completion+0x3b2/0x700 fs/fs-writeback.c:227 __writeback_inodes_sb_nr+0x246/0x2e0 fs/fs-writeback.c:2933 sync_filesystem+0xa2/0x250 fs/sync.c:54 generic_shutdown_super+0x77/0x2d0 fs/super.c:626 kill_block_super+0x44/0x90 fs/super.c:1665 deactivate_locked_super+0xbc/0x130 fs/super.c:477 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8664abf097 RSP: 002b:00007fffbb054ea8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f8664b532ca RCX: 00007f8664abf097 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffbb054f60 RBP: 00007fffbb054f60 R08: 00007fffbb055f60 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffbb055ff0 R13: 00007f8664b532ca R14: 0000000000162c0c R15: 00007fffbb056030 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:10/1026: #0: ffff88801fa8f138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88801fa8f138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc90005c7fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90005c7fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 8 locks held by aoe_tx0/1338: 2 locks held by dhcpcd/5258: #0: ffff88803910c928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe7/0xee0 net/netlink/af_netlink.c:2273 #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dump_ifinfo+0xa74/0x14b0 net/core/rtnetlink.c:2562 2 locks held by getty/5350: #0: ffff888032ac80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211 3 locks held by kworker/u8:16/6870: #0: ffff888032a7a138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff888032a7a138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc9000413fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc9000413fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4229 3 locks held by kworker/u8:31/9676: #0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc900015cfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc900015cfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 1 lock held by syz-executor/12502: #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509 11 locks held by kworker/u8:2/19157: 2 locks held by syz-executor/19828: #0: ffff888062cf4f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:497 [inline] #0: ffff888062cf4f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x22a/0x5b0 net/bluetooth/hci_core.c:2678 #1: ffff888062cf40b0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x61f/0x10a0 net/bluetooth/hci_sync.c:5393 5 locks held by syz-executor/19844: #0: ffff888034e76500 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline] #0: ffff888034e76500 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #1: ffff8880325efc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336 #2: ffff88802997ca58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff88802997ca58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337 #3: ffffffff8ebe7118 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff88803ffbd160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #4: ffff88803ffbd160 (&dev->mutex){....}-{4:4}, at: device_del+0xa9/0x8f0 drivers/base/core.c:3923 4 locks held by syz-executor/19848: #0: ffff888034e76500 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline] #0: ffff888034e76500 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #1: ffff88803a033078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336 #2: ffff88802997ca58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff88802997ca58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337 #3: ffffffff8ebe7118 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 2 locks held by syz-executor/19970: #0: ffffffff8f8d0b18 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f8d0b18 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8f8d0b18 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158 1 lock held by syz.2.1216/20032: #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 1 lock held by syz.2.1216/20035: #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888036d5e0d0 (&type->s_umount_key#73){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 2 locks held by syz-executor/20060: #0: ffffffff8f8b20f8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f8b20f8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8f8b20f8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158 2 locks held by syz-executor/20066: #0: ffffffff8f8cf1e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f8cf1e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8f8cf1e0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158 1 lock held by syz-executor/20082: #0: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3bf/0x1e10 drivers/net/tun.c:3148 2 locks held by syz-executor/20091: #0: ffffffff8f362b20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575 #1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d5/0x820 net/ipv4/ip_tunnel.c:1149 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 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+0xfd7/0x1030 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: 19157 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: netns cleanup_net RIP: 0010:__bfs kernel/locking/lockdep.c:1753 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline] RIP: 0010:__lock_acquire+0x17a5/0x2ce0 kernel/locking/lockdep.c:5237 Code: 00 00 0f 83 84 01 00 00 4e 8b 3c e5 a0 29 79 95 ff c0 25 ff 0f 00 00 89 05 28 d8 d8 13 4d 85 ff 0f 84 ac 01 00 00 49 8b 47 10 <48> 85 c0 0f 84 38 0d 00 00 8b 0d 14 d8 d8 13 39 48 5c 0f 84 6a ff RSP: 0018:ffffc90003a2e490 EFLAGS: 00000082 RAX: ffffffff93258e08 RBX: 00000000000003cd RCX: ffffffff9637ad38 RDX: ffffffff93207650 RSI: ffff88802f580dc0 RDI: 00000000000003cd RBP: 85167a1978380eaf R08: ffffc90003a2e458 R09: 0000000000000020 R10: 0000000000000000 R11: ffffffff81a124a0 R12: 0000000000000197 R13: ffff88802f580dc0 R14: ffff88802f580000 R15: ffffffff9637ad38 FS: 0000000000000000(0000) GS:ffff888126211000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562692d6c000 CR3: 0000000052002000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73 ktime_get+0x45/0x220 kernel/time/timekeeping.c:971 hrtick_start+0x99/0x250 kernel/sched/core.c:980 enqueue_task+0x75/0x410 kernel/sched/core.c:2184 sched_change_end+0x213/0x600 kernel/sched/core.c:11255 migrate_disable_switch kernel/sched/core.c:2465 [inline] __schedule+0x1879/0x5500 kernel/sched/core.c:7089 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5945 Code: 1a 00 00 b8 ff ff ff ff 65 0f c1 05 8c bd 49 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 5b c6 03 00 cc 90 0f 0b 90 48 c7 RSP: 0018:ffffc90003a2eab0 EFLAGS: 00000206 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 0000000000000100 RSI: ffffffff8d8a5064 RDI: ffffffff8ba94380 RBP: 00000000ffffffff R08: ffffffff82696e8e R09: 0000000000000000 R10: 0000000000000000 R11: ffff88801a08f100 R12: 0000000000000246 R13: ffff88802f580000 R14: ffffffff8dfc3080 R15: 0000000000000009 lock_is_held include/linux/lockdep.h:249 [inline] __might_resched+0x37/0x480 kernel/sched/core.c:9159 __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline] rt_spin_lock+0xc2/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] __kernfs_new_node+0x11e/0xa70 fs/kernfs/dir.c:670 kernfs_new_node+0xea/0x140 fs/kernfs/dir.c:751 __kernfs_create_file+0x4b/0x2e0 fs/kernfs/file.c:1050 sysfs_add_file_mode_ns+0x237/0x300 fs/sysfs/file.c:316 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x679/0x1180 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 device_add_groups drivers/base/core.c:2907 [inline] device_add_attrs+0x1b1/0x600 drivers/base/core.c:2982 device_add+0x488/0xb80 drivers/base/core.c:3711 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2337 register_netdevice+0x1455/0x1ed0 net/core/dev.c:11440 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1070 [inline] nsim_create+0xbe9/0x1150 drivers/net/netdevsim/netdev.c:1152 __nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1509 nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1570 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1622 [inline] nsim_dev_reload_up+0x4dd/0x880 drivers/net/netdevsim/dev.c:1058 devlink_reload+0x4bb/0x890 net/devlink/dev.c:475 devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:560 ops_pre_exit_list net/core/net_namespace.c:161 [inline] ops_undo_list+0x17d/0x8d0 net/core/net_namespace.c:234 cleanup_net+0x575/0x810 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 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