INFO: task syz.3.1840:13684 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1840      state:D stack:27728 pid:13684 ppid:4282   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
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 ___down_common kernel/locking/semaphore.c:229 [inline]
 __down_common+0x321/0x7a0 kernel/locking/semaphore.c:250
 down+0x7c/0xd0 kernel/locking/semaphore.c:64
 console_lock+0x141/0x1c0 kernel/printk/printk.c:2629
 con_install+0x94/0x720 drivers/tty/vt/vt.c:3384
 tty_driver_install_tty drivers/tty/tty_io.c:1305 [inline]
 tty_init_dev+0xcf/0x4c0 drivers/tty/tty_io.c:1417
 tty_open_by_driver drivers/tty/tty_io.c:2083 [inline]
 tty_open+0x7d8/0xd80 drivers/tty/tty_io.c:2130
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3838
 do_filp_open+0x1ee/0x420 fs/namei.c:3865
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 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: 0033:0x7fc60836034e
RSP: 002b:00007fc60922ab28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc60922b6c0 RCX: 00007fc60836034e
RDX: 0000000000000002 RSI: 00007fc60922ac00 RDI: ffffffffffffff9c
RBP: 00007fc608437b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc608626128 R14: 00007fc608626090 R15: 00007ffee193e588
 </TASK>
INFO: task syz.0.1878:13824 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1878      state:D stack:27888 pid:13824 ppid:13206  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
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6719
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x562/0xb40 kernel/locking/mutex.c:747
 tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3838
 do_filp_open+0x1ee/0x420 fs/namei.c:3865
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 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: 0033:0x7f2ac416034e
RSP: 002b:00007f2ac5149b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f2ac514a6c0 RCX: 00007f2ac416034e
RDX: 0000000000000002 RSI: 00007f2ac5149c00 RDI: ffffffffffffff9c
RBP: 00007f2ac4237b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2ac4426038 R14: 00007f2ac4425fa0 R15: 00007ffe147baaa8
 </TASK>

Showing all locks held in the system:
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
2 locks held by getty/4029:
 #0: ffff88814cae9098 (&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
2 locks held by kworker/u4:23/4451:
1 lock held by syz.6.1652/12908:
2 locks held by syz.3.1840/13684:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
 #1: ffff88805aaf51c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x70/0x4c0 drivers/tty/tty_io.c:1416
1 lock held by syz.0.1878/13824:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.9.1919/13962:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.2.1947/14083:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.5.1967/14192:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.1.1981/14269:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
3 locks held by syz-executor/14294:
1 lock held by syz.3.2084/14716:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.8.2292/15407:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.8.2292/15408:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.4.2390/15748:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.7.2392/15754:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.9.2429/15909:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by syz.9.2429/15911:
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0: ffffffff8e2853e8 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xd80 drivers/tty/tty_io.c:2130
1 lock held by sed/15962:

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

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>