INFO: task syz.2.2383:13392 blocked for more than 143 seconds.
      Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.2383      state:D stack:27944 pid:13392 tgid:13389 ppid:5846   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1360
 sync_bdevs+0x1ac/0x340
 ksys_sync+0xb9/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7cf5d8ebe9
RSP: 002b:00007f7cf6c86038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7cf5fb6090 RCX: 00007f7cf5d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7cf5fb6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7cf5fb6128 R14: 00007f7cf5fb6090 R15: 00007ffc13c27f68
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:6/1093:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90006f47bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f537cc8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
5 locks held by kworker/0:2/1778:
1 lock held by dhcpcd/5593:
 #0: ffffffff8f537cc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_deladdr+0x198/0x740
2 locks held by getty/5673:
 #0: ffff888027bf70a0 (&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/u8:3/5876:
 #0: ffff888020edc148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000477fbc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f537cc8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30
4 locks held by kworker/u8:4/5910:
 #0: ffff88801b2f7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000495fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f52ae70 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
 #3: ffffffff8f537cc8 (rtnl_mutex){+.+.}-{4:4}, at: ieee80211_unregister_hw+0x55/0x2c0
1 lock held by udevd/12048:
 #0: ffff888109a78358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.2.2383/13392:
 #0: ffff888109a78358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
4 locks held by syz-executor/15663:
 #0: ffff888027f0e428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
 #1: ffff888121720088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0
 #2: ffff88801ff45d28 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0
 #3: ffffffff8edaee28 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360
8 locks held by syz-executor/15666:
 #0: ffff888027f0e428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
 #1: ffff888131bb1088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0
 #2: ffff88801ff45d28 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0
 #3: ffffffff8edaee28 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360
 #4: ffff88812303e0e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800
 #5: ffff88811ffa6250 (&devlink->lock_key#11){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160
 #6: ffffffff8f537cc8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xe5/0x670
 #7: ffffffff8dfd3010 (cpu_hotplug_lock){++++}-{0:0}, at: unregister_netdevice_many_notify+0x8de/0x1ff0
4 locks held by syz-executor/15669:
 #0: ffff888027f0e428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
 #1: ffff888131bb2488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0
 #2: ffff88801ff45d28 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0
 #3: ffffffff8edaee28 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094-dirty #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: 1778 Comm: kworker/0:2 Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094-dirty #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_power_efficient neigh_periodic_work
RIP: 0010:native_apic_msr_write+0x39/0x50
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 d2 68 8e 03 66
RSP: 0018:ffffc900000067d8 EFLAGS: 00000046
RAX: 0000000000002939 RBX: ffff88804b023900 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 0000000000002939 RDI: 0000000000000838
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ae027e
R10: 0000000000000003 R11: ffffffff81703490 R12: 0000000010001ad7
R13: dffffc0000000000 R14: 0000000000002939 R15: 0000000000000020
FS:  0000000000000000(0000) GS:ffff8880b861c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe079a4fa8 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x1cf/0x360
 hrtimer_start_range_ns+0xda6/0x1080
 netem_dequeue+0x1260/0x1430
 __qdisc_run+0x23c/0x15f0
 __dev_queue_xmit+0x1056/0x3b50
 ip6_finish_output2+0x11bc/0x16a0
 synproxy_send_tcp_ipv6+0x4c1/0x680
 synproxy_send_client_synack_ipv6+0x80e/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
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 neigh_periodic_work+0xc28/0xe50
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
