INFO: task kworker/0:1:13 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1     state:D stack:23840 pid:   13 ppid:     2 flags:0x00004000
Workqueue: events console_callback
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 __down_common+0x289/0x3b0 kernel/locking/semaphore.c:228
 down+0x7e/0xd0 kernel/locking/semaphore.c:63
 console_lock+0x29/0x70 kernel/printk/printk.c:2557
 console_callback+0x66/0x440 drivers/tty/vt/vt.c:2980
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz.5.156:5085 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.156       state:D stack:27888 pid: 5085 ppid:  4554 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7f7/0xf90 fs/open.c:826
 do_open fs/namei.c:3659 [inline]
 path_openat+0x2718/0x2fb0 fs/namei.c:3793
 do_filp_open+0x1df/0x400 fs/namei.c:3820
 do_sys_openat2+0x14b/0x500 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc2e32c3159
RSP: 002b:00007fc2e151b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc2e354afa0 RCX: 00007fc2e32c3159
RDX: 0000000000040801 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007fc2e335a06b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc2e354b038 R14: 00007fc2e354afa0 R15: 00007ffc0219ca88
 </TASK>
INFO: task syz.4.158:5117 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.158       state:D stack:28464 pid: 5117 ppid:  4191 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 __down_common+0x289/0x3b0 kernel/locking/semaphore.c:228
 down+0x7e/0xd0 kernel/locking/semaphore.c:63
 console_lock+0x29/0x70 kernel/printk/printk.c:2557
 store_bind+0x59/0xa20 drivers/tty/vt/vt.c:3920
 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2179 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb4fcbcb159
RSP: 002b:00007fb4fae02028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb4fce53090 RCX: 00007fb4fcbcb159
RDX: 0000000000000010 RSI: 0000200000002bc0 RDI: 0000000000000004
RBP: 00007fb4fcc6206b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb4fce53128 R14: 00007fb4fce53090 R15: 00007ffd84d6dc28
 </TASK>
INFO: task syz.4.158:5120 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.158       state:D stack:29072 pid: 5120 ppid:  4191 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 __fdget_pos+0x2bf/0x370 fs/file.c:1056
 fdget_pos include/linux/file.h:76 [inline]
 ksys_write+0x77/0x260 fs/read_write.c:638
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb4fcbcb159
RSP: 002b:00007fb4fade1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb4fce53180 RCX: 00007fb4fcbcb159
RDX: 0000000000000001 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007fb4fcc6206b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb4fce53218 R14: 00007fb4fce53180 R15: 00007ffd84d6dc28
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:1/13:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90000d27d00 (console_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:2/154:
2 locks held by getty/3949:
 #0: ffff88814ce92098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
5 locks held by kworker/0:5/4234:
 #0: ffff888017a9bd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900031cfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff888024220220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #2: ffff888024220220 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5260 drivers/usb/core/hub.c:5832
 #3: ffff8880242235c8 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3173 [inline]
 #3: ffff8880242235c8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5398 [inline]
 #3: ffff8880242235c8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5642 [inline]
 #3: ffff8880242235c8 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5804 [inline]
 #3: ffff8880242235c8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x20a7/0x5260 drivers/usb/core/hub.c:5886
 #4: ffff888024159c68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5399 [inline]
 #4: ffff888024159c68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5642 [inline]
 #4: ffff888024159c68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5804 [inline]
 #4: ffff888024159c68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x20d1/0x5260 drivers/usb/core/hub.c:5886
3 locks held by syz.1.128/4954:
1 lock held by syz.5.156/5085:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
4 locks held by syz.4.158/5117:
 #0: ffff888020e75c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88807f12e460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffff8880624a6488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #3: ffff8880203e4008 (kn->active#696){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
1 lock held by syz.4.158/5120:
 #0: ffff888020e75c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
1 lock held by syz.3.201/5370:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.8.181/5480:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.7.233/5643:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.1.235/5837:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.9.271/5894:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.5.304/6141:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.2.300/6296:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.3.416/6594:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz-executor/6845:
1 lock held by syz.0.510/6855:
3 locks held by syz.8.526/6905:
 #0: ffff88805f729a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff88805f729a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff88805f729a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
 #1: ffff888052950120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #1: ffff888052950120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pptp_release+0x4d/0x2d0 drivers/net/ppp/pptp.c:512
 #2: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>