INFO: task jbd2/sda1-8:2814 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:jbd2/sda1-8 state:D stack:26216 pid:2814 tgid:2814 ppid:2 task_flags:0x240040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xeb1/0x4220 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 io_schedule+0x8a/0xf0 kernel/sched/core.c:7835 bit_wait_io+0xd/0xe0 kernel/sched/wait_bit.c:250 __wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0xdc/0x110 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:105 [inline] __wait_on_buffer+0x64/0x70 fs/buffer.c:124 wait_on_buffer include/linux/buffer_head.h:420 [inline] journal_wait_on_commit_record fs/jbd2/commit.c:171 [inline] jbd2_journal_commit_transaction+0x49a6/0x6900 fs/jbd2/commit.c:881 kjournald2+0x200/0x760 fs/jbd2/journal.c:201 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff896de760 (rcu_read_lock){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] , at: rcu_read_lock include/linux/rcupdate.h:850 [inline] , at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:6/158: 2 locks held by getty/2917: #0: ffff888112cfe0a0 ( &tty->ldisc_sem ){++++}-{0:0} , at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 ( &ldata->atomic_read_lock ){+.+.}-{4:4} , at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:3/5216: #0: ffff888105acc548 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc9000305fd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffff8881093b81e0 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff8881344e21e0 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068 #4: ffff888101298188 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:796 7 locks held by kworker/1:4/5221: 4 locks held by udevd/5229: #0: ffff888135aaed58 ( &p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88810f341488 ( &of->mutex ){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888105b59008 ( kn->active #9 ){++++}-{0:0} , at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] , at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88811d5701e0 ( &dev->mutex ){....}-{4:4} , at: device_lock_interruptible include/linux/device.h:954 [inline] , at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 3 locks held by kworker/1:6/5376: 4 locks held by udevd/5439: 8 locks held by kworker/0:6/5611: #0: ffff888105acc548 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc9000307fd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffff88810b7581e0 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88811e42e1e0 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff8881149191a8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: __device_driver_lock drivers/base/dd.c:1166 [inline] , at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1364 #5: ffff888141d31a68 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:949 [inline] , at: __device_driver_lock drivers/base/dd.c:1166 [inline] , at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1364 #6: ffffffff8a50be68 ( input_mutex ){+.+.}-{4:4} , at: class_mutex_constructor include/linux/mutex.h:253 [inline] , at: __input_unregister_device+0x184/0x4d0 drivers/input/input.c:2187 #7: ffffffff896ea2b8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 2 locks held by kworker/1:7/6693: 3 locks held by kworker/u8:1/8213: 6 locks held by kworker/0:9/9781: 2 locks held by kworker/1:0/10500: 2 locks held by kworker/u8:2/12508: #0: ffff8881000ac948 ( (wq_completion)events_unbound #2 ){+.+.}-{0:0} , at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc90003197d18 ( (work_completion)(&sub_info->work) ){+.+.}-{0:0} , at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 1 lock held by syz-executor/12781: 1 lock held by syz-executor/12782: 1 lock held by syz-executor/12783: 1 lock held by syz-executor/12788: #0: ffff888101298188 (&root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x740 fs/kernfs/dir.c:1185 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xd25/0x1050 kernel/hung_task.c:515 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 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: yealink 2-1:36.0: unexpected response 0 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5221 Comm: kworker/1:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_power_efficient gc_worker RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:408 Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 e1 78 f5 fe eb a0 e8 6a 79 f5 RSP: 0018:ffffc900001a8430 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: ffffffff83208635 RDI: ffffffff941b8be0 RBP: ffffffff941b8ba0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff941b8bf0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8882687c9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1c30455980 CR3: 00000000094ae000 CR4: 00000000003506f0 Call Trace: serial_out drivers/tty/serial/8250/8250.h:133 [inline] serial8250_clear_IER+0xa7/0xd0 drivers/tty/serial/8250/8250_port.c:716 serial8250_console_write+0x252/0x1900 drivers/tty/serial/8250/8250_port.c:3322 console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269 console_flush_all kernel/printk/printk.c:3343 [inline] __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0x103/0x260 kernel/printk/printk.c:3413 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479 dev_vprintk_emit+0x394/0x3e0 drivers/base/core.c:4915 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4926 __dev_printk+0xcb/0x100 drivers/base/core.c:4938 _dev_err+0xef/0x127 drivers/base/core.c:4981 urb_irq_callback.cold+0x81/0xfd drivers/input/misc/yealink.c:435 __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741 dummy_timer+0xda1/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:2005 __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x50e/0xa70 kernel/time/hrtimer.c:1849 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1866 handle_softirqs+0x1de/0x9d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xed/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0xf5/0x140 kernel/locking/lockdep.c:5945 Code: ff ff ff ff 65 0f c1 15 81 c8 8b 05 83 fa 01 8b 44 24 04 75 2d 9c 5a 80 e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 <5b> 5d 41 5c 41 5d 41 5e 41 5f e9 0c df 02 00 e9 07 df 02 00 31 c0 RSP: 0018:ffffc9000308faa8 EFLAGS: 00000282 RAX: 0000000000000000 RBX: ffffffff896de700 RCX: 0000000000000001 RDX: 0000000000000046 RSI: ffffffff890036c1 RDI: ffffffff87afd320 RBP: ffff888118e98000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000246 R14: ffff888118e98b20 R15: 0000000000000002 lock_is_held include/linux/lockdep.h:249 [inline] __might_resched+0x248/0x330 kernel/sched/core.c:8850 gc_worker+0x966/0x1630 net/netfilter/nf_conntrack_core.c:1618 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245