INFO: task syz.0.1477:7827 blocked for more than 430 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1477      state:D stack:0     pid:7827  tgid:7826  ppid:7111   task_flags:0x400040 flags:0x00000019
Call trace:
 __switch_to+0x208/0x4f0 arch/arm64/kernel/process.c:741 (T)
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0xd58/0x3180 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xd0/0x344 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x72c/0xffc kernel/locking/mutex.c:760
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:812
 sync_bdevs+0xe4/0x2a0 block/bdev.c:1288
 ksys_sync+0xc8/0x150 fs/sync.c:105
 __arm64_sys_sync+0x10/0x20 fs/sync.c:113
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x288 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Showing all locks held in the system:
no locks held by rcu_preempt/15.
1 lock held by pr/ttyAMA-1/31:
1 lock held by khungtaskd/32:
 #0: ffff800087371ea0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x18/0x1c4 kernel/locking/lockdep.c:6769
3 locks held by kworker/u8:3/81:
 #0: ffff00000dc31148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6f8/0x18d4 kernel/workqueue.c:3238
 #1: ffff80008dc47c90 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x71c/0x18d4 kernel/workqueue.c:3238
 #2: ffff800088966088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x1c/0x28 net/core/rtnetlink.c:80
6 locks held by kworker/u8:9/1627:
2 locks held by getty/3262:
 #0: ffff000017a300a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80008d68b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x3e8/0xdc0 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/3317:
3 locks held by kworker/u8:7/4014:
1 lock held by udevd/7585:
 #0: ffff0000147f4358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x2c4/0xa84 block/bdev.c:945
1 lock held by syz.0.1477/7827:
 #0: ffff0000147f4358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0xe4/0x2a0 block/bdev.c:1288
1 lock held by syz.2.1840/8838:

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