INFO: task syz.4.305:6135 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.4.305       state:D stack:0     pid:6135  tgid:6134  ppid:4707   task_flags:0x400040 flags:0x00800011
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
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x5d4/0x1078 kernel/locking/mutex.c:821
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874
 sync_bdevs+0x214/0x3d4 block/bdev.c:1369
 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+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
INFO: task syz.4.305:6140 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.4.305       state:D stack:0     pid:6140  tgid:6134  ppid:4707   task_flags:0x400040 flags:0x00800011
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
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x5d4/0x1078 kernel/locking/mutex.c:821
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874
 sync_bdevs+0x214/0x3d4 block/bdev.c:1369
 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+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: ffff800088c41960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff800088c41960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff800088c41960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x4c/0x188 kernel/locking/lockdep.c:6871
locks held by getty/4490: 2, on CPU#0:
 #0: ffff0000d15b20a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009241b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x348/0xf78 drivers/tty/n_tty.c:2211
locks held by udevd/4701: 1, on CPU#1:
 #0: ffff0000c78cf350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xc4/0x880 block/bdev.c:990
locks held by kworker/u8:23/5503: 2, on CPU#1:
 #0: ffff0001adf061e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x44 kernel/sched/core.c:677
 #1: ffff0001adef0248 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:218 [inline]
 #1: ffff0001adef0248 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2308/0x2b00 kernel/sched/core.c:7278
locks held by syz.4.305/6135: 1, on CPU#1:
 #0: ffff0000c78cf350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x214/0x3d4 block/bdev.c:1369
locks held by syz.4.305/6140: 1, on CPU#1:
 #0: ffff0000c78cf350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x214/0x3d4 block/bdev.c:1369

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