INFO: task syz.5.2395:11615 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.5.2395      state:D stack:26648 pid:11615 tgid:11609 ppid:8940   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5630
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 write_versions+0x95/0xe30
 nfsctl_transaction_write+0x10f/0x160
 vfs_write+0x296/0xba0
 ksys_write+0x150/0x270
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa2c399e159
RSP: 002b:00007fa2c485d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa2c3c26090 RCX: 00007fa2c399e159
RDX: 0000000000000009 RSI: 0000200000000540 RDI: 0000000000000003
RBP: 00007fa2c3a3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa2c3c26128 R14: 00007fa2c3c26090 R15: 00007ffe794dc288
 </TASK>
INFO: task syz.5.2395:11624 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.5.2395      state:D stack:27432 pid:11624 tgid:11609 ppid:8940   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5630
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 write_threads+0x39d/0x5a0
 nfsctl_transaction_write+0x10f/0x160
 vfs_write+0x296/0xba0
 ksys_write+0x150/0x270
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa2c399e159
RSP: 002b:00007fa2c483c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa2c3c26180 RCX: 00007fa2c399e159
RDX: 0000000000000002 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007fa2c3a3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa2c3c26218 R14: 00007fa2c3c26180 R15: 00007ffe794dc288
 </TASK>

Showing all locks held in the system:
locks held by ksoftirqd/0/15: 1, last CPU#0:
 #0: ffff88812103b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160
locks held by khungtaskd/34: 1, last CPU#1:
 #0: ffffffff8eb5a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by kworker/u10:2/68: 2, on CPU#1:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0
 #1: ffffc90001797c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0
locks held by kworker/0:3/5057: 5, last CPU#0:
 #0: ffff888105695540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0
 #1: ffffc900034cfc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0
 #2: ffff88816b33d1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30
 #3: ffff8881164071d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff88811e5001a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
locks held by getty/5419: 2, on CPU#1:
 #0: ffff8881722810a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by syz.5.2395/11610: 3, on CPU#1:
 #0: ffff88816d9d8af0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff88811162a460 (sb_writers#42){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10
locks held by syz.5.2395/11615: 3, on CPU#0:
 #0: ffff888105f1a0f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff88811162a460 (sb_writers#42){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30
locks held by syz.5.2395/11624: 3, on CPU#1:
 #0: ffff88816bcf4af0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff88811162a460 (sb_writers#42){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x39d/0x5a0
locks held by syz-executor/12065: 2, on CPU#1:
 #0: ffff88817269e0e8 (&type->s_umount_key#96){++++}-{4:4}, at: deactivate_super+0xac/0xe0
 #1: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
locks held by syz-executor/14818: 2, on CPU#1:
 #0: ffff88811289e0e8 (&type->s_umount_key#96){++++}-{4:4}, at: deactivate_super+0xac/0xe0
 #1: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
locks held by syz.2.4029/15379: 1, on CPU#0:
 #0: ffff88817269e0e8 (&type->s_umount_key#96){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.1.4799/17467: 1, last CPU#0:
 #0: ffff88812103b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160
locks held by syz.9.4806/17484: 1, on CPU#1:
 #0: ffffffff8eb603e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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: 5522 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:deref_stack_reg+0x4a/0x220
Code: df 48 83 c7 08 49 89 fc 49 c1 ec 03 41 80 3c 34 00 4c 89 04 24 74 13 e8 94 24 bd 00 4c 8b 04 24 48 be 00 00 00 00 00 fc ff df <48> 89 5c 24 08 49 8b 6f 08 49 8d 7f 10 49 89 fd 49 c1 ed 03 41 80
RSP: 0018:ffffc90000007898 EFLAGS: 00000246
RAX: fffffffffffffff0 RBX: ffffc900000079c8 RCX: 0000000000000000
RDX: ffffc900000079c8 RSI: dffffc0000000000 RDI: ffffc90000007990
RBP: 1ffffffff22efa2d R08: ffffc900048efb70 R09: 0000000000000000
R10: ffffc900000079d8 R11: fffff52000000f3d R12: 1ffff92000000f32
R13: ffffffff9177d16d R14: ffffc90000007988 R15: ffffc90000007988
FS:  0000555594a40540(0000) GS:ffff88818d939000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7dc79ef2f8 CR3: 0000000112000000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 unwind_next_frame+0x19bd/0x2550
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x40/0x50
 __kasan_slab_free+0x5c/0x80
 __rcu_free_sheaf_prepare+0x12d/0x2a0
 rcu_free_sheaf+0x31/0x200
 rcu_core+0x794/0x10b0
 handle_softirqs+0x226/0x860
 do_softirq+0x77/0xd0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x140
 tcp_recvmsg+0x1df/0x7f0
 sock_recvmsg+0x166/0x1e0
 sock_read_iter+0x22a/0x2f0
 vfs_read+0x595/0xa80
 ksys_read+0x150/0x270
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f337c9592d7
Code: 48 89 fa 4c 89 df e8 a8 56 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff5d629460 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000555594a40540 RCX: 00007f337c9592d7
RDX: 0000000000000004 RSI: 00007fff5d6294bc RDI: 0000000000000003
RBP: 00007fff5d629960 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004
R13: 00007fff5d6294bc R14: 00007fff5d629550 R15: 0000000000000000
 </TASK>
