INFO: task syz.4.523:8462 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.523       state:D stack:0     pid:8462  tgid:8459  ppid:6672   task_flags:0x400140 flags:0x00000801
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7376
 cgroup_lock_and_drain_offline+0x490/0x604 kernel/cgroup/cgroup.c:3350
 cgroup1_get_tree+0xa0/0x7d8 kernel/cgroup/cgroup-v1.c:1265
 vfs_get_tree+0x90/0x28c fs/super.c:1932
 fc_mount+0x24/0xac fs/namespace.c:1198
 do_new_mount_fc fs/namespace.c:3772 [inline]
 do_new_mount+0x2a4/0x538 fs/namespace.c:3848
 path_mount+0x5f0/0xa88 fs/namespace.c:4168
 do_mount+0xe8/0x148 fs/namespace.c:4181
 __do_sys_mount fs/namespace.c:4397 [inline]
 __se_sys_mount fs/namespace.c:4374 [inline]
 __arm64_sys_mount+0x33c/0x388 fs/namespace.c:4374
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x19c/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606

Showing all locks held in the system:
locks held by khungtaskd/31: 1, last CPU#0:
 #0: ffff800088c618e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff800088c618e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff800088c618e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x4c/0x188 kernel/locking/lockdep.c:6871
locks held by getty/4487: 2, on CPU#0:
 #0: ffff0000d11bb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009246e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x348/0xf78 drivers/tty/n_tty.c:2211

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