INFO: task syz.6.3901:17771 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.3901      state:D stack:27432 pid:17771 tgid:17770 ppid:17582  task_flags:0x400140 flags:0x00004006
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: 0033:0x7f341918ebe9
RSP: 002b:00007f341a0cd038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f34193b5fa0 RCX: 00007f341918ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f34193b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f34193b6038 R14: 00007f34193b5fa0 R15: 00007ffcca711a78
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5674:
 #0: ffff888020b380a0 (&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 syz-executor/8111:
1 lock held by syz.6.3901/17771:
 #0: ffff88812048e0e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.4947/20355:
 #0: ffff88812048e0e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.5076/20736:
 #0: ffffffff8e13f938 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
6 locks held by syz.0.5078/20740:

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

NMI backtrace for cpu 0
CPU: 0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20740 Comm: syz.0.5078 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:__kasan_check_byte+0x12/0x40
Code: cf fe ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 56 53 48 89 f3 49 89 fe e8 5e 14 00 00 <84> c0 75 16 be 01 00 00 00 4c 89 f7 31 d2 48 89 d9 89 c3 e8 c6 03
RSP: 0000:ffffc900001dfac0 EFLAGS: 00000293
RAX: 0000000000000001 RBX: ffffffff8172c1b2 RCX: a10c0758177bc100
RDX: 0000000000000000 RSI: ffffffff8172c1b2 RDI: 1ffffffff1c273d4
RBP: ffffffff8172c195 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900001dfc98 R11: ffffffff81ac3910 R12: 0000000000000002
R13: ffffffff8e139ea0 R14: ffffffff8e139ea0 R15: 0000000000000000
FS:  00007fdc871866c0(0000) GS:ffff8881a3c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000029000 CR3: 000000002eeea000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 lock_acquire+0x8d/0x360
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 synproxy_send_client_synack_ipv6+0x169/0xca0
 nft_synproxy_eval_v6+0x36e/0x560
 nft_synproxy_do_eval+0x3d7/0x570
 nft_do_chain+0x40c/0x1920
 nft_do_chain_inet+0x25d/0x340
 nf_hook_slow+0xc5/0x220
 NF_HOOK+0x206/0x3a0
 ip6_input+0x16a/0x270
 NF_HOOK+0x30c/0x3a0
 __netif_receive_skb+0xd3/0x380
 process_backlog+0x60e/0x14f0
 __napi_poll+0xc7/0x360
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_call_function_single+0xa3/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x1a/0x20
RIP: 0010:kvm_sched_clock_read+0xc/0x20
Code: 00 65 c6 05 9f fc 26 07 00 eb 9a cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 3d 54 37 27 07 <e8> 4f 00 00 00 48 2b 05 30 ae 44 02 e9 13 e8 02 00 cc cc cc 90 90
RSP: 0000:ffffc90006c772a8 EFLAGS: 00000283
RAX: ffffffff822c7068 RBX: ffffea0000ef94c0 RCX: ffff88801fff3980
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff92a68040
RBP: 0000000000000000 R08: ffffea0000ef94f7 R09: 1ffffd40001df29e
R10: dffffc0000000000 R11: fffff940001df29f R12: dffffc0000000000
R13: ffffea0000ef9400 R14: ffffea0000ef94c0 R15: 0000000000000000
 local_clock_noinstr+0xc/0xe0
 local_clock+0x10/0x30
 __reset_page_owner+0x1d/0x1f0
 free_unref_folios+0xdbd/0x1520
 folios_put_refs+0x559/0x640
 free_pages_and_swap_cache+0x277/0x520
 tlb_flush_mmu+0x3a0/0x680
 tlb_finish_mmu+0xc3/0x1d0
 exit_mmap+0x44c/0xb50
 __mmput+0x118/0x420
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdc8638ebe9
Code: Unable to access opcode bytes at 0x7fdc8638ebbf.
RSP: 002b:00007fdc871860e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 00007fdc865b5fa8 RCX: 00007fdc8638ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdc865b5fa8
RBP: 00007fdc865b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdc865b6038 R14: 00007fff1cc392c0 R15: 00007fff1cc393a8
 </TASK>
