INFO: task syz.1.1366:13194 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1366      state:D stack:27584 pid:13194 tgid:13193 ppid:5598   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 md_allow_write+0x3b3/0x520
 raid1_reshape+0x383/0x14a0
 chunk_size_store+0x2e1/0x480
 md_attr_store+0x3b7/0x640
 kernfs_fop_write_iter+0x3a4/0x540
 vfs_write+0x612/0xba0
 ksys_write+0x150/0x270
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f929ef9f559
RSP: 002b:00007f929fdef028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f929f225fa0 RCX: 00007f929ef9f559
RDX: 0000000000000014 RSI: 00002000000021c0 RDI: 0000000000000004
RBP: 00007f929f036b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f929f226038 R14: 00007f929f225fa0 R15: 00007ffc46c50428
 </TASK>

Showing all locks held in the system:
locks held by kworker/0:0/9: 1, last CPU#0:
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: process_scheduled_works+0x97a/0x1630
locks held by khungtaskd/37: 1, last CPU#1:
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by kworker/u9:2/363: 3, last CPU#0:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90003c3fc40 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffff888120e3bd60 (&rq->__lock){-.-.}-{2:2}, at: finish_task_switch+0x159/0xc60
locks held by getty/5417: 2, on CPU#1:
 #0: ffff8881174040a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034932e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by kworker/0:5/5670: 1, last CPU#0:
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: process_scheduled_works+0x97a/0x1630
locks held by syz.1.1366/13194: 4, on CPU#1:
 #0: ffff888117d9c460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #1: ffff888114d17c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540
 #2: ffff8881098ab3c8 (kn->active#76){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540
 #3: ffff8881ba2d4358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: chunk_size_store+0xbb/0x480

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 363 Comm: kworker/u9:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound idle_cull_fn
RIP: 0010:__lock_acquire+0x1860/0x2de0
Code: 05 3d 73 f9 15 48 b8 00 00 00 00 01 00 00 00 48 89 05 24 73 f9 15 48 8d 84 24 90 00 00 00 48 89 05 15 f3 f8 15 31 ff 45 31 ff <4d> 85 ff 4c 8b 74 24 10 74 2e 49 8b 47 30 48 85 c0 74 25 48 8b 40
RSP: 0018:ffffc90003c3f250 EFLAGS: 00000046
RAX: ffffffff953f5500 RBX: 00000000000003dd RCX: 0000000000037f76
RDX: 0000000000000008 RSI: ffff888104f00c28 RDI: 00000000000003dd
RBP: b4ced01ab1f2ae5b R08: ffffc90003c3f218 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a3ec50 R12: 00000000000002f0
R13: ffffffff953d41f0 R14: ffff888104f00c28 R15: ffffffff98231518
FS:  0000000000000000(0000) GS:ffff88818c4bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34f1dff8 CR3: 0000000117f9a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x115/0x350
 _raw_spin_lock_irqsave+0x40/0x60
 hrtimer_start_range_ns+0x8c/0x3e0
 finish_task_switch+0x3c0/0xc60
 __schedule+0x17e3/0x58f0
 schedule+0x164/0x2b0
 schedule_timeout+0xc0/0x2c0
 wait_for_completion+0x2ca/0x5e0
 kthread_stop+0x183/0x5b0
 kthread_stop_put+0x1a/0xa0
 idle_cull_fn+0x671/0x740
 process_scheduled_works+0xc3d/0x1630
 worker_thread+0xa47/0xfb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
