INFO: task syz.4.2544:16132 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2544      state:D stack:27784 pid:16132 ppid:15960  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5393 [inline]
 __schedule+0x156f/0x4720 kernel/sched/core.c:6722
 schedule+0xbd/0x170 kernel/sched/core.c:6796
 schedule_timeout+0xc1/0x2d0 kernel/time/timer.c:2144
 ___down_common kernel/locking/semaphore.c:229 [inline]
 __down_common+0x31f/0x6b0 kernel/locking/semaphore.c:250
 down+0x80/0xd0 kernel/locking/semaphore.c:64
 console_lock+0x145/0x1b0 kernel/printk/printk.c:2686
 con_install+0x98/0x720 drivers/tty/vt/vt.c:3334
 tty_driver_install_tty drivers/tty/tty_io.c:1304 [inline]
 tty_init_dev+0xd3/0x4c0 drivers/tty/tty_io.c:1416
 tty_open_by_driver drivers/tty/tty_io.c:2082 [inline]
 tty_open+0x7e2/0xd90 drivers/tty/tty_io.c:2129
 chrdev_open+0x58c/0x600 fs/char_dev.c:414
 do_dentry_open+0x880/0x14b0 fs/open.c:929
 do_open fs/namei.c:3695 [inline]
 path_openat+0x284f/0x3270 fs/namei.c:3856
 do_filp_open+0x1f2/0x430 fs/namei.c:3883
 do_sys_openat2+0x134/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5051b6974e
RSP: 002b:00007f5052a1eb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5052a1f6c0 RCX: 00007f5051b6974e
RDX: 0000000000000002 RSI: 00007f5052a1ec00 RDI: ffffffffffffff9c
RBP: 00007f5051c37f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5051e26038 R14: 00007f5051e25fa0 R15: 00007ffc3afc6fd8
 </TASK>
INFO: task syz.5.2571:16250 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2571      state:D stack:26120 pid:16250 ppid:8950   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5393 [inline]
 __schedule+0x156f/0x4720 kernel/sched/core.c:6722
 schedule+0xbd/0x170 kernel/sched/core.c:6796
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6855
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x689/0xce0 kernel/locking/mutex.c:747
 ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823
 chrdev_open+0x58c/0x600 fs/char_dev.c:414
 do_dentry_open+0x880/0x14b0 fs/open.c:929
 do_open fs/namei.c:3695 [inline]
 path_openat+0x284f/0x3270 fs/namei.c:3856
 do_filp_open+0x1f2/0x430 fs/namei.c:3883
 do_sys_openat2+0x134/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3bd3ba8f19
RSP: 002b:00007f3bd4b43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f3bd3e25fa0 RCX: 00007f3bd3ba8f19
RDX: 0000000000101002 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f3bd3c37f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3bd3e26038 R14: 00007f3bd3e25fa0 R15: 00007ffe58417938
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669
2 locks held by kworker/u4:7/1100:
 #0: ffff888018c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff888018c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc900045dfd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc900045dfd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
3 locks held by kworker/u4:10/1142:
2 locks held by getty/5542:
 #0: ffff88802f78d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000327e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x43a/0x1400 drivers/tty/n_tty.c:2217
4 locks held by syz-executor/13539:
6 locks held by syz.6.2479/15817:
2 locks held by syz.4.2544/16132:
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline]
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x211/0xd90 drivers/tty/tty_io.c:2129
 #1: ffff88802a2551c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x74/0x4c0 drivers/tty/tty_io.c:1415
1 lock held by syz.5.2571/16250:
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.1.2631/16657:
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.0.2736/17187:
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.7.2831/17637:
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline]
 #0: ffffffff8e8abb28 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x211/0xd90 drivers/tty/tty_io.c:2129
2 locks held by syz.9.2997/18310:
1 lock held by modprobe/18311:
1 lock held by syz.2.2999/18313:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf59/0xfa0 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>