INFO: task syz.3.407:9172 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.407       state:D stack:25032 pid:9172  tgid:9171  ppid:8461   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f713bb8ebe9
RSP: 002b:00007f713cab8038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f713bdc5fa0 RCX: 00007f713bb8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f713bdc5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f713bdc6038 R14: 00007f713bdc5fa0 R15: 00007fffea9b3208
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:1/68:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000174fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
2 locks held by dhcpcd/5594:
 #0: ffff88812e9526d0 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xbd/0xe90
 #1: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200
2 locks held by getty/5677:
 #0: ffff8881085930a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by kworker/1:7/7470:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000417fbc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
3 locks held by kworker/0:8/8120:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000346fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888032c40240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
3 locks held by syz-executor/8274:
1 lock held by syz.3.407/9172:
 #0: ffff88811e0ba0e0 (&type->s_umount_key#87){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.715/11307:
 #0: ffff88811e0ba0e0 (&type->s_umount_key#87){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.715/11320:
 #0: ffff88811e0ba0e0 (&type->s_umount_key#87){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by syz-executor/11717:
 #0: ffffffff8eca89e0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70
6 locks held by syz.8.769/11742:
2 locks held by syz.4.770/11745:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 11745 Comm: syz.4.770 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:__lock_acquire+0x467/0xd20
Code: c5 45 8d 7c 24 01 49 ff cc 44 89 f9 83 c1 fe 78 44 44 89 e3 81 e3 ff ff ff 7f 83 f9 31 73 1d 48 8d 0c 9b 8b 8c cf 10 0b 00 00 <31> c1 41 ff cf 49 ff cc f7 c1 00 60 00 00 74 cf eb 1c 48 c7 c7 d0
RSP: 0018:ffffc9000666f2c8 EFLAGS: 00000083
RAX: 000000000002001a RBX: 0000000000000001 RCX: 0000000000020007
RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffff888108659cc0
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff822e619a
R10: dffffc0000000000 R11: ffffed10220b74de R12: 0000000000000001
R13: 0000000000000001 R14: ffff88810865a828 R15: 0000000000000003
FS:  00007f51804e66c0(0000) GS:ffff8880b8618000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557fa37808 CR3: 0000000030a4c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 pfn_valid+0xd6/0x490
 page_table_check_clear+0x21/0x700
 unmap_page_range+0x340f/0x4370
 unmap_vmas+0x399/0x580
 vms_clear_ptes+0x35c/0x540
 vms_complete_munmap_vmas+0x206/0x8a0
 do_vmi_align_munmap+0x358/0x420
 do_vmi_munmap+0x253/0x2e0
 __vm_munmap+0x23b/0x3d0
 __x64_sys_munmap+0x60/0x70
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f517f58ec77
Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f51804e5e18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007f517f58ec77
RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007f5175200000
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000054ff
R10: 0000200000002482 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f51804e5ef0 R14: 00007f51804e5eb0 R15: 00007f5175200000
 </TASK>
