INFO: task syz.8.4452:19703 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.4452      state:D stack:27216 pid:19703 ppid: 19099 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
 do_con_write+0xfb/0x6c40 drivers/tty/vt/vt.c:2908
 con_write+0x1f/0x40 drivers/tty/vt/vt.c:3295
 process_output_block drivers/tty/n_tty.c:592 [inline]
 n_tty_write+0xd19/0x1220 drivers/tty/n_tty.c:2339
 do_tty_write drivers/tty/tty_io.c:1038 [inline]
 file_tty_write+0x50c/0x8a0 drivers/tty/tty_io.c:1110
 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: 0033:0x7f8de71e2159
RSP: 002b:00007f8de543a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8de7469fa0 RCX: 00007f8de71e2159
RDX: 0000000000001006 RSI: 0000200000001040 RDI: 0000000000000004
RBP: 00007f8de727906b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8de746a038 R14: 00007f8de7469fa0 R15: 00007fff7c1bf078
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by dhcpcd/3850:
 #0: ffff88801fadc690 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0xf5/0x720 net/netlink/af_netlink.c:2363
 #1: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0x70a/0xdd0 net/netlink/af_netlink.c:2290
2 locks held by getty/3942:
 #0: ffff88802bdf5098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
1 lock held by syz.5.1253/9028:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: tty_release_struct+0xaa/0xd0 drivers/tty/tty_io.c:1718
2 locks held by kworker/0:29/17951:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900033ffd00 (console_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
5 locks held by syz.0.4172/18717:
4 locks held by syz.8.4452/19703:
 #0: ffff8880274c6098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffff8880274c6130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:961 [inline]
 #1: ffff8880274c6130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:984 [inline]
 #1: ffff8880274c6130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write+0x23c/0x8a0 drivers/tty/tty_io.c:1110
 #2: ffff8880274c62e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1ec/0x1220 drivers/tty/n_tty.c:2322
 #3: ffffc90003f13378 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:547 [inline]
 #3: ffffc90003f13378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x66a/0x1220 drivers/tty/n_tty.c:2339
2 locks held by syz.7.4631/20346:
 #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: ffff888060d6e1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x6f/0x470 drivers/tty/tty_io.c:1430
1 lock held by syz.9.4709/20658:
 #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
2 locks held by udevd/21027:
1 lock held by syz.4.4874/21341:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.0.5200/22831:
 #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.6.5226/23023:
 #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
3 locks held by kworker/u4:3/23878:
1 lock held by syz.2.5384/24115:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.5.5445/24415:
 #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.9.5490/24655:
 #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.3.5578/25179:
 #0: ffffffff8c9f6768 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz-executor/25218:
3 locks held by syz.1.5596/25285:
2 locks held by syz.7.5604/25319:
2 locks held by syz.4.5606/25327:

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

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>