INFO: task kworker/u8:16:3202 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/u8:16 state:D stack:21392 pid:3202 tgid:3202 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:2) Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 io_schedule+0x7f/0xd0 kernel/sched/core.c:8110 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:1584 [inline] __writeback_single_inode+0x6af/0xf90 fs/fs-writeback.c:1827 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2056 wb_writeback+0x41c/0xad0 fs/fs-writeback.c:2241 wb_do_writeback fs/fs-writeback.c:2388 [inline] wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 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:9874 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:22352 pid:9874 tgid:9874 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 wb_wait_for_completion+0x3b2/0x700 fs/fs-writeback.c:227 __writeback_inodes_sb_nr+0x246/0x2e0 fs/fs-writeback.c:2847 sync_filesystem+0xa2/0x250 fs/sync.c:54 generic_shutdown_super+0x77/0x2d0 fs/super.c:625 kill_block_super+0x44/0x90 fs/super.c:1725 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1312 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:67 [inline] exit_to_user_mode_loop+0x193/0x6b0 kernel/entry/common.c:98 __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: 0033:0x7f0d523ae097 RSP: 002b:00007ffda932bee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f0d524421ca RCX: 00007f0d523ae097 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffda932bfa0 RBP: 00007ffda932bfa0 R08: 00007ffda932cfa0 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffda932d030 R13: 00007f0d524421ca R14: 000000000007a179 R15: 00007ffda932d070 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 5 locks held by kworker/u8:7/1025: #0: ffff88801aac8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801aac8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc90005f87c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc90005f87c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f139760 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673 #3: ffff8880697dd878 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:249 #4: ffffffff8ddcdcf0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3828 2 locks held by kworker/u8:9/1464: #0: ffff888019c34938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888019c34938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc90006c67c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc90006c67c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 2 locks held by kworker/0:2/1683: #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc90007287c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc90007287c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 2 locks held by kworker/u8:16/3202: #0: ffff88801f2c8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801f2c8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc9000ec8fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc9000ec8fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 2 locks held by getty/5364: #0: ffff88803733b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cd32e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1390 drivers/tty/n_tty.c:2211 1 lock held by udevd/5614: #0: ffff88801c294480 (sb_writers){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 4 locks held by kworker/u9:2/5616: #0: ffff88802499d938 ((wq_completion)hci3#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88802499d938 ((wq_completion)hci3#2){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc900044ffc40 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc900044ffc40 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffff8880606fc0b0 (&hdev->lock){+.+.}-{4:4}, at: hci_conn_complete_evt+0xba/0x1350 net/bluetooth/hci_event.c:3117 #3: ffff888019c3f238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_activate fs/kernfs/dir.c:1463 [inline] #3: ffff888019c3f238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x2b7/0x5d0 fs/kernfs/dir.c:869 1 lock held by syz-executor/9874: #0: ffff888021ff60d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888021ff60d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff888021ff60d0 (&type->s_umount_key#73){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 3 locks held by syz-executor/9921: 2 locks held by syz-executor/10000: #0: ffff888031c8c480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888026242168 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] #1: ffff888026242168 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2914 [inline] #1: ffff888026242168 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2938 [inline] #1: ffff888026242168 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: filename_rmdir+0x1cd/0x520 fs/namei.c:5424 1 lock held by syz-executor/11587: 8 locks held by syz-executor/12101: 1 lock held by udevadm/12275: 2 locks held by syz.8.762/12279: 2 locks held by modprobe/12284: ============================================= NMI backtrace for cpu 1 CPU: 1 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: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+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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11587 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5599 [inline] RIP: 0010:lock_is_held_type+0x78/0x150 kernel/locking/lockdep.c:5940 Code: 48 c7 c7 39 74 41 8d e8 66 1b 00 00 65 ff 05 2f 2f 31 07 41 83 bd f0 0b 00 00 00 7e 48 4c 89 eb 48 81 c3 f8 0b 00 00 45 31 ff <49> 83 ff 31 73 24 48 89 df 4c 89 f6 e8 f7 01 00 00 85 c0 75 2a 49 RSP: 0018:ffffc90004a1f6c0 EFLAGS: 00000093 RAX: 0000000000000004 RBX: ffff88803ae42b08 RCX: 0000000000000046 RDX: 0000000000000006 RSI: ffff88813fffc358 RDI: ffff88803ae42ae0 RBP: 00000000ffffffff R08: ffffffff8f67c9f7 R09: 1ffffffff1ecf93e R10: dffffc0000000000 R11: fffffbfff1ecf93f R12: 0000000000000246 R13: ffff88803ae41ec0 R14: ffff88813fffc358 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8881263a1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6177f56000 CR3: 000000007bf96000 CR4: 00000000003526f0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] account_freepages mm/page_alloc.c:773 [inline] __free_one_page+0x14d/0xb30 mm/page_alloc.c:952 free_pcppages_bulk+0x303/0x520 mm/page_alloc.c:1495 free_frozen_page_commit+0x65a/0x1850 mm/page_alloc.c:2876 __free_frozen_pages+0x8a0/0x1100 mm/page_alloc.c:2965 vfree+0x251/0x3b0 mm/vmalloc.c:3472 kcov_put kernel/kcov.c:444 [inline] kcov_close+0x2e/0x60 kernel/kcov.c:543 __fput+0x42a/0xa80 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:976 do_group_exit+0x22d/0x2f0 kernel/exit.c:1119 get_signal+0x121b/0x12c0 kernel/signal.c:3038 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x6b0 kernel/entry/common.c:98 __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: 0033:0x7f09180ad68e Code: Unable to access opcode bytes at 0x7f09180ad664. RSP: 002b:00007ffc8a53bce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 0000000000000003 RBX: 000055558a25c500 RCX: 00007f09180ad68e RDX: 0000000000000003 RSI: 00007ffc8a53bd70 RDI: 0000000000000005 RBP: 00007f0918183616 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffc8a53bd70 R14: 00007f0918e94620 R15: 0000000000000003