INFO: task syz-executor:7119 blocked for more than 127 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:7119  tgid:7119  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
 rcu_barrier+0x4d/0x530 kernel/rcu/tree.c:4589
 netdev_run_todo+0x10e/0xcb0 net/core/dev.c:10868
 rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
 tun_detach drivers/net/tun.c:704 [inline]
 tun_chr_close+0xc5/0x150 drivers/net/tun.c:3517
 __fput+0x1fe/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e3/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9bc/0x2630 kernel/exit.c:953
 do_group_exit+0x22a/0x300 kernel/exit.c:1095
 get_signal+0x139d/0x14f0 kernel/signal.c:2933
 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fd070b84e13
RSP: 002b:00007ffc89697928 EFLAGS: 00000202 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 0000000000000068 RCX: 00007fd070b84e13
RDX: 0000000040000000 RSI: 00007ffc8969796c RDI: 00000000ffffffff
RBP: 00007ffc8969796c R08: 00000000390040e9 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000025
R13: 0000555579ede470 R14: 000000000002de52 R15: 00007ffc896979c0
 </TASK>
INFO: task syz.7.2304:7456 blocked for more than 134 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.2304      state:D stack:0     pid:7456  tgid:7456  ppid:6477   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
 rcu_barrier+0x4d/0x530 kernel/rcu/tree.c:4589
 rcu_sync_dtor+0xaf/0x170 kernel/rcu/sync.c:187
 percpu_free_rwsem+0x44/0x90 kernel/locking/percpu-rwsem.c:57
 hci_uart_tty_close+0x210/0x230 drivers/bluetooth/hci_ldisc.c:564
 tty_ldisc_close drivers/tty/tty_ldisc.c:455 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:613 [inline]
 tty_ldisc_release+0x2aa/0x600 drivers/tty/tty_ldisc.c:781
 tty_release_struct+0x2d/0xe0 drivers/tty/tty_io.c:1690
 tty_release+0xc0a/0x1230 drivers/tty/tty_io.c:1861
 __fput+0x1fe/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e3/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9bc/0x2630 kernel/exit.c:953
 do_group_exit+0x22a/0x300 kernel/exit.c:1095
 get_signal+0x139d/0x14f0 kernel/signal.c:2933
 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7ffadc84d9b0
RSP: 002b:00007fffd1e5b4b8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007ffadd6f5720 RCX: 0000000000001326
RDX: 00007fffd1e5b4c0 RSI: 00007fffd1e5b5f0 RDI: 0000000000000011
RBP: ffffffff81560ea4 R08: 00007ffadcbc6038 R09: 00007ffadcbb2000
R10: 00007ffadc3ff008 R11: 000000000000000f R12: 000000000000000f
R13: 0000000000000000 R14: ffffffff83188193 R15: 0000000000001326
 </TASK>