INFO: task s
INFO: task syz.1.850:9253 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.1.850       state:D stack:0     pid:9253  tgid:9251  ppid:6890   task_flags:0x400040 flags:0x00000011
Call trace:
 __switch_to+0x2b0/0x6e0 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x1370/0x2d80 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7326
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7383
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x4ec/0xf14 kernel/locking/mutex.c:821
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874
 sync_bdevs+0x214/0x3d4 block/bdev.c:1297
 ksys_sync+0xc4/0x118 fs/sync.c:105
 __arm64_sys_sync+0x14/0x24 fs/sync.c:111
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x4c/0x188 kernel/locking/lockdep.c:6775
2 locks held by pr/ttyAMA-1/41:
2 locks held by getty/4491:
 #0: ffff0000d10d20a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009248b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x348/0xf78 drivers/tty/n_tty.c:2211
1 lock held by udevd/4848:
 #0: ffff0000c636d350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by udevd/4864:
 #0: ffff0000c6d0d350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by udevd/5719:
 #0: ffff0000c520d350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by udevd/5720:
 #0: ffff0000c6e1f350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by udevd/5721:
 #0: ffff0000c6d09350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
2 locks held by kworker/u8:21/5908:
 #0: ffff0000c004c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff0000c004c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x734/0x10b8 kernel/workqueue.c:3405
 #1: ffff8000973e7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffff8000973e7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x73c/0x10b8 kernel/workqueue.c:3405
1 lock held by syz.1.850/9253:
 #0: ffff0000c6e1f350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x214/0x3d4 block/bdev.c:1297
2 locks held by syz-executor/9994:
1 lock held by udevd/11220:
 #0: ffff0000c6e1d350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by udevd/11225:
 #0: ffff0000c5209350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:948
1 lock held by syz.7.2425/15285:

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