INFO: task syz.0.254:5249 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.254       state:D stack:27888 pid:5249  ppid:4279   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x1089/0x4140 kernel/sched/core.c:6584
 schedule+0xb9/0x180 kernel/sched/core.c:6660
 rwsem_down_write_slowpath+0xc9c/0x11a0 kernel/locking/rwsem.c:1189
 tty_set_termios+0x146/0x17e0 drivers/tty/tty_ioctl.c:355
 set_termios+0x4fe/0x680 drivers/tty/tty_ioctl.c:537
 tty_mode_ioctl+0x51e/0x6a0 drivers/tty/tty_ioctl.c:-1
 tty_ioctl+0x878/0xba0 drivers/tty/tty_io.c:2802
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb9b959f559
RSP: 002b:00007fb9ba388028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb9b9825fa0 RCX: 00007fb9b959f559
RDX: 0000200000000540 RSI: 0000000000005406 RDI: 0000000000000003
RBP: 00007fb9b9636b50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb9b9826038 R14: 00007fb9b9825fa0 R15: 00007ffca45a1738
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/0:0/7:
 #0: ffff8881436ba938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900000c7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff8880298f7190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #2: ffff8880298f7190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5855
 #3: ffff88802994a500 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3210 [inline]
 #3: ffff88802994a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5423 [inline]
 #3: ffff88802994a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5667 [inline]
 #3: ffff88802994a500 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5827 [inline]
 #3: ffff88802994a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x2076/0x5200 drivers/usb/core/hub.c:5909
 #4: ffff88802929c168 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5424 [inline]
 #4: ffff88802929c168 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5667 [inline]
 #4: ffff88802929c168 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5827 [inline]
 #4: ffff88802929c168 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x20a1/0x5200 drivers/usb/core/hub.c:5909
 #5: ffffffff8e686e10 (ehci_cf_port_reset_rwsem){.+.+}-{3:3}, at: hub_port_reset+0x151/0x18d0 drivers/usb/core/hub.c:3067
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8db2e3f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xce0 kernel/rcu/tasks.h:543
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8db2ec30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xce0 kernel/rcu/tasks.h:543
1 lock held by khungtaskd/28:
 #0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
4 locks held by kworker/u4:3/47:
2 locks held by getty/4034:
 #0: ffff88814caa4098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x430/0x1400 drivers/tty/n_tty.c:2198
3 locks held by kworker/0:5/4360:
 #0: ffff888018470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004527d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff8880796b6240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x283/0x3320 drivers/net/netdevsim/fib.c:1491
5 locks held by syz.1.20/4501:
2 locks held by syz.0.254/5249:
 #0: ffff88807dbad098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffff88807dbad2e8 (&tty->termios_rwsem){++++}-{3:3}, at: tty_set_termios+0x146/0x17e0 drivers/tty/tty_ioctl.c:355
3 locks held by kworker/0:11/6493:
 #0: ffff888030ca8138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003257d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4146
2 locks held by syz.7.658/6850:
 #0: ffff88807dbad098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffff88807dbad2e8 (&tty->termios_rwsem){++++}-{3:3}, at: set_termios+0x12e/0x680 drivers/tty/tty_ioctl.c:474
2 locks held by udevd/7012:
1 lock held by syz-executor/7391:
1 lock held by syz-executor/7453:
1 lock held by syz.1.798/7476:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>