INFO: task syz-executor:5861 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:18856 pid:5861 tgid:5861 ppid:1 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216 sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2834 sync_filesystem+0x17a/0x230 fs/sync.c:64 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622 kill_block_super+0x44/0x90 fs/super.c:1766 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3cd3b8eba9 RSP: 002b:00007ffebcc67708 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f3cd3c11c65 RCX: 00007f3cd3b8eba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000c R08: 00007ffebcc654a6 R09: 00007ffebcc689c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffebcc689c0 R13: 00007f3cd3c11c05 R14: 000055558baef4a8 R15: 00007ffebcc69a90 Showing all locks held in the system: 2 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/31: #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:2/36: 2 locks held by kworker/1:2/55: #0: ffff88801a478d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a478d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90000bf7bc0 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90000bf7bc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 2 locks held by kworker/u8:5/1023: #0: ffff88801cacf948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801cacf948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90003647bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90003647bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 2 locks held by kworker/u8:6/1338: 2 locks held by dhcpcd/5523: #0: ffffffff8f51e408 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x5ee/0x790 net/socket.c:1321 #1: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xd0/0x650 net/8021q/vlan.c:577 2 locks held by getty/5625: #0: ffff88814d2d20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036c62f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz-executor/5861: #0: ffff88807e7ea0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807e7ea0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807e7ea0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff888024c9a7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888024c9a7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2832 2 locks held by syz-executor/5863: #0: ffff88802ff660e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802ff660e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802ff660e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff888143b047d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888143b047d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2832 2 locks held by syz-executor/5865: #0: ffff88807ddd40e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807ddd40e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807ddd40e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff8881437fe7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8881437fe7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2832 2 locks held by syz-executor/5869: #0: ffff88805553c0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88805553c0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88805553c0e0 (&type->s_umount_key#77){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff8881437f87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8881437f87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2832 4 locks held by kworker/1:7/6030: 3 locks held by kworker/1:8/6031: #0: ffff88801a478d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a478d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000ac4fbc0 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000ac4fbc0 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8e13fa40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815 5 locks held by kworker/u8:10/7108: #0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90003d4fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90003d4fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8f52d090 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658 #3: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1c/0x1d0 drivers/net/wireguard/device.c:417 #4: ffff888027a114e8 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_netns_pre_exit+0xb0/0x1d0 drivers/net/wireguard/device.c:422 1 lock held by segctord/7301: 3 locks held by segctord/7452: 1 lock held by segctord/7530: 4 locks held by syz-executor/8000: #0: ffff88807b768dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] #0: ffff88807b768dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715 #1: ffff88807b7680b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282 #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2094 [inline] #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2599 #3: ffff88805524cb38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 net/bluetooth/l2cap_core.c:1762 3 locks held by kworker/u8:14/8031: #0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc900037ffbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc900037ffbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 3 locks held by syz-executor/8094: #0: ffff88807f690dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] #0: ffff88807f690dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715 #1: ffff88807f6900b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282 #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2094 [inline] #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2599 3 locks held by syz-executor/8153: #0: ffff88805564cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] #0: ffff88805564cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715 #1: ffff88805564c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282 #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2094 [inline] #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2599 3 locks held by syz-executor/8347: #0: ffff88807d590dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] #0: ffff88807d590dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715 #1: ffff88807d5900b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282 #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2094 [inline] #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2599 3 locks held by syz-executor/8374: #0: ffff88807b76cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] #0: ffff88807b76cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715 #1: ffff88807b76c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282 #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2094 [inline] #2: ffffffff8f69ede8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2599 2 locks held by dhcpcd/8395: #0: ffff88802ef7a258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline] #0: ffff88802ef7a258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3251 #1: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957 ============================================= 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:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 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: 7301 Comm: segctord Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__list_add_valid_or_report+0x6d/0x130 lib/list_debug.c:32 Code: 00 74 08 4c 89 e7 e8 72 84 52 fd 4d 39 34 24 75 71 4d 89 f4 49 c1 ec 03 43 80 3c 2c 00 74 08 4c 89 f7 e8 56 84 52 fd 49 39 1e <0f> 85 83 00 00 00 4d 39 f7 74 17 49 39 df 74 12 b0 01 5b 41 5c 41 RSP: 0018:ffffc900034875a0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff888043eb5538 RCX: ffffffff8245bfba RDX: ffff888043eb5538 RSI: ffff888043eb5538 RDI: ffff888058eec300 RBP: 1ffff110087d6aa8 R08: ffff888058eec2bf R09: 1ffff1100b1dd857 R10: dffffc0000000000 R11: ffffed100b1dd858 R12: 1ffff110087d6aa7 R13: dffffc0000000000 R14: ffff888043eb5538 R15: ffff888058eec300 FS: 0000000000000000(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558130757138 CR3: 0000000030d3a000 CR4: 0000000000350ef0 Call Trace: __list_add_valid include/linux/list.h:88 [inline] __list_add include/linux/list.h:150 [inline] list_add_tail include/linux/list.h:183 [inline] nilfs_segbuf_add_segsum_buffer fs/nilfs2/segbuf.h:138 [inline] nilfs_segbuf_extend_segsum+0x2a1/0x3b0 fs/nilfs2/segbuf.c:110 nilfs_segbuf_reset+0x37/0x140 fs/nilfs2/segbuf.c:135 nilfs_segctor_reset_segment_buffer fs/nilfs2/segment.c:423 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1543 [inline] nilfs_segctor_do_construct+0x1334/0x6a40 fs/nilfs2/segment.c:2122 nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2462 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2570 [inline] nilfs_segctor_thread+0x6f7/0xe00 fs/nilfs2/segment.c:2684 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245