INFO: task syz.3.1188:8737 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1188      state:D stack:27464 pid:8737  tgid:8736  ppid:8546   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c4/0x15a0
 write_ports+0xb5/0xd10
 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: 0033:0x7fd43b39f559
RSP: 002b:00007fd43c1df028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd43b625fa0 RCX: 00007fd43b39f559
RDX: 0000000000000005 RSI: 00002000000001c0 RDI: 0000000000000003
RBP: 00007fd43b436b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd43b626038 R14: 00007fd43b625fa0 R15: 00007ffee07b4a08
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/35: 1, last CPU#1:
 #0: ffffffff8fd588e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5421: 2, on CPU#1:
 #0: ffff8881159cf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000348b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by syz.0.1110/8469: 3, on CPU#0:
 #0: ffff88816a9154f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160
 #1: ffff8881bf120460 (sb_writers#30){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff9009c060 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10
locks held by syz.3.1188/8737: 3, on CPU#0:
 #0: ffff88802162baf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160
 #1: ffff888024490460 (sb_writers#30){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff9009c060 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10
locks held by syz-executor/9302: 7, last CPU#0:
 #0: ffffffff8fe32670 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x470
 #1: ffff888118acd900 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0
 #2: ffff8881194c0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0
 #3: ffffffff8fd588e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240
 #4: ffff8881bb322a98 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: fs_reclaim_acquire+0x7c/0x100
 #5: ffff8881194c13c0 (key){....}-{2:2}, at: percpu_counter_add_batch+0x116/0x1d0
 #6: ffff8881133d6a38 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x6fb/0x5c00
locks held by syz.7.3586/15322: 1, last CPU#1:
 #0: ffff8881bf760988 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 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+0xfd2/0x1030
 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: 9302 Comm: syz-executor 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
RIP: 0010:__this_cpu_preempt_check+0x0/0x20
Code: f5 48 8b 74 24 20 48 c7 c7 00 f5 6d 8c e8 f8 fb 3c f5 e8 93 fb 47 f5 eb ae 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 89 fe 48 c7 c7 80 f4 6d 8c e9 0d ff ff ff cc cc cc
RSP: 0018:ffffc9000f1671e0 EFLAGS: 00000046
RAX: ee8391300075277b RBX: 0000000000000202 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8fd589a0 RDI: ffffffff8e6f6868
RBP: ffff888109aa8cc8 R08: ffffffff8244d94a R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1023253b05 R12: 0000000000000007
R13: 0000000000000007 R14: ffffffff8fd589a0 R15: ffff888109aa8000
FS:  0000555575ce7500(0000) GS:ffff88818c4b1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8d1d3556c8 CR3: 0000000021502000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_release+0x263/0x3c0
 pfn_valid+0x3bb/0x490
 page_table_check_set+0x25/0x530
 copy_pmd_range+0x4adc/0x5c00
 copy_page_range+0xc7d/0x1280
 dup_mmap+0xf17/0x1dc0
 copy_mm+0x115/0x470
 copy_process+0x1ecc/0x44b0
 kernel_clone+0x2d7/0x940
 __x64_sys_clone+0x1b6/0x230
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d1c5c7fd2
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffd44309df0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffd44309df0 RCX: 00007f8d1c5c7fd2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffd44309f7c R08: 0000000000000000 R09: 0000000000000001
R10: 0000555575ce77d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 0000000000042c94 R15: 00007ffd44309fd0
 </TASK>
