INFO: task kworker/u8:1:13 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:1 state:D stack:20264 pid:13 tgid:13 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:820 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x6f1/0x1000 fs/fs-writeback.c:1745 writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaf4/0xf00 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 3 locks held by kworker/0:0/9: 2 locks held by kworker/0:1/10: 4 locks held by kworker/u8:1/13: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880487e20d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888036865990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff888036865990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 1 lock held by khungtaskd/38: #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:2/43: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90000b47bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90000b47bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880237b00d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888054b15990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff888054b15990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 6 locks held by kworker/u8:3/58: #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000124fbc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000124fbc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff88805714f300 (&devlink->lock_key#4){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:853 #3: ffff888036c77d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] #3: ffff888036c77d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:806 [inline] #3: ffff888036c77d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:866 #4: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #4: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #4: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #4: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1bb/0x2c0 kernel/locking/spinlock_rt.c:57 #5: ffff8880b88365d0 ((crngs.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] #5: ffff8880b88365d0 ((crngs.lock)){+.+.}-{3:3}, at: crng_make_state+0x8f/0x2b0 drivers/char/random.c:368 4 locks held by kworker/u8:4/69: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000154fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000154fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880612220d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff8880270d9990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff8880270d9990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 4 locks held by kworker/u8:7/1184: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90004b1fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90004b1fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880357080d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888035435990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff888035435990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 4 locks held by kworker/u8:12/3850: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000df07bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000df07bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880295420d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888038c79990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff888038c79990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 4 locks held by kworker/u8:13/3893: #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8881404bb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000e317bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000e317bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880576160d0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88803d3e9990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] #3: ffff88803d3e9990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 2 locks held by getty/5597: #0: ffff88823bf4a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222 3 locks held by kworker/u9:2/5963: #0: ffff88805931d938 ((wq_completion)hci3){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88805931d938 ((wq_completion)hci3){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90004ebfbc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90004ebfbc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff888034424e80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d4/0x3a0 net/bluetooth/hci_sync.c:331 6 locks held by syz.0.17/6122: 5 locks held by syz.1.18/6187: 5 locks held by syz.2.19/6220: 6 locks held by syz.3.20/6246: 2 locks held by kworker/u8:14/6278: 5 locks held by syz.4.21/6280: 4 locks held by syz.5.22/6320: 4 locks held by syz.6.24/6358: 3 locks held by syz-executor/6369: ============================================= 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 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+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 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: 6358 Comm: syz.6.24 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__lock_release kernel/locking/lockdep.c:5544 [inline] RIP: 0010:lock_release+0x140/0x3e0 kernel/locking/lockdep.c:5889 Code: eb 48 8d 6c dd 00 48 89 ef 4c 89 f6 e8 a9 21 5b 09 44 89 64 24 14 45 89 e5 85 c0 0f 84 dd 00 00 00 48 85 ed 0f 84 19 01 00 00 <83> 7d 24 00 0f 85 ea 01 00 00 8b 45 20 3d 00 00 20 00 48 8b 5c 24 RSP: 0018:ffffc9000508ea30 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000014 RCX: 4c01ad67e152b900 RDX: ffffc9000508ef60 RSI: ffff8880558431a0 RDI: ffff888039476500 RBP: ffff888039476500 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffff52000a11d44 R12: 0000000000000004 R13: 0000000000000004 R14: ffff8880558431a0 R15: ffff888039475940 FS: 000055558aff2500(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559f15d9ea38 CR3: 000000003c252000 CR4: 00000000003526f0 Call Trace: up_read+0x16/0x40 kernel/locking/rwsem.c:1632 f2fs_up_read fs/f2fs/f2fs.h:2229 [inline] f2fs_get_node_info+0x1e8/0x1520 fs/f2fs/node.c:582 is_alive fs/f2fs/gc.c:1152 [inline] gc_data_segment fs/f2fs/gc.c:1579 [inline] do_garbage_collect+0x220d/0x6410 fs/f2fs/gc.c:1826 f2fs_gc+0xca9/0x2580 fs/f2fs/gc.c:1931 f2fs_balance_fs+0x5fb/0x7f0 fs/f2fs/segment.c:466 f2fs_map_blocks+0x345f/0x4130 fs/f2fs/data.c:1792 f2fs_expand_inode_data+0x5b1/0xa60 fs/f2fs/file.c:1923 f2fs_fallocate+0x4f8/0x990 fs/f2fs/file.c:2026 vfs_fallocate+0x672/0x7f0 fs/open.c:342 ioctl_preallocate fs/ioctl.c:290 [inline] file_ioctl+0x61d/0x780 fs/ioctl.c:-1 do_vfs_ioctl+0xb36/0x1440 fs/ioctl.c:577 __do_sys_ioctl fs/ioctl.c:596 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584 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: 0033:0x7fe652e1eec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffcbe2a0b58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe653075fa0 RCX: 00007fe652e1eec9 RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004 RBP: 00007fe652ea1f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe653075fa0 R14: 00007fe653075fa0 R15: 0000000000000003