INFO: task syz.0.895:11038 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.895       state:D stack:28936 pid:11038 tgid:11029 ppid:8611   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 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: 0033:0x7f7c51f8ebe9
RSP: 002b:00007f7c52e3f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7c521c6180 RCX: 00007f7c51f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7c521c6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c521c6218 R14: 00007f7c521c6180 R15: 00007fffb91ceff8
 </TASK>
INFO: task syz.0.895:11041 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.895       state:D stack:25896 pid:11041 tgid:11029 ppid:8611   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 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: 0033:0x7f7c51f8ebe9
RSP: 002b:00007f7c52e1e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7c521c6270 RCX: 00007f7c51f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7c521c6270 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c521c6308 R14: 00007f7c521c6270 R15: 00007fffb91ceff8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u10:0/27:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0
 #2: ffff888136625918 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
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/u10:3/998:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffffc90006ab7bc0 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: bpf_trace_run4+0x19c/0x4a0
 #2: ffff888136625918 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
6 locks held by kworker/0:2/1272:
3 locks held by klogd/5286:
2 locks held by getty/5682:
 #0: ffff888106e470a0 (&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
2 locks held by kworker/u8:3/5879:
1 lock held by udevd/6670:
 #0: ffff88810817b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
5 locks held by kworker/1:12/9029:
 #0: ffff88810524c148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002bffbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810a1e6198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88810a289518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20
 #4: ffff88810a21cd68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20
1 lock held by syz.0.895/11038:
 #0: ffff88810817b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.0.895/11041:
 #0: ffff88810817b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.8.1059/11761:
 #0: ffff88810817b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.1.1301/13261:
 #0: ffff88810817b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.2.1319/13384:

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

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: 13384 Comm: syz.2.1319 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+0xc9/0x360
Code: 03 11 85 c0 0f 85 eb 00 00 00 65 48 8b 04 25 08 50 a0 92 83 b8 ec 0a 00 00 00 0f 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c <8f> 44 24 30 4c 89 74 24 10 4d 89 fe 4c 8b 7c 24 30 fa 48 c7 c7 1c
RSP: 0018:ffffc90000006df0 EFLAGS: 00000246
RAX: ffff88801f71b980 RBX: 0000000000000000 RCX: da61b83ab7360100
RDX: 0000000000000000 RSI: ffffffff8a2b62cf RDI: 1ffffffff1c273dc
RBP: ffffffff8a2b62ae R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000a888 R11: 0000000000000100 R12: 0000000000000002
R13: ffffffff8e139ee0 R14: 0000000000000000 R15: 0000000000000000
FS:  00007ffb8a28c6c0(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3371aff8 CR3: 000000011abb8000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 ip6_rcv_core+0xbf/0x1590
 ipv6_rcv+0x72/0xc0
 __netif_receive_skb+0xd3/0x380
 netif_receive_skb+0x1cb/0x790
 NF_HOOK+0xa0/0x390
 br_handle_frame_finish+0x14d1/0x19b0
 br_nf_hook_thresh+0x3c6/0x4a0
 br_nf_pre_routing_finish_ipv6+0x948/0xd00
 br_nf_pre_routing_ipv6+0x37e/0x6b0
 br_handle_frame+0x982/0x14c0
 __netif_receive_skb_core+0x10b9/0x4020
 __netif_receive_skb+0x72/0x380
 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_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110
Code: 74 05 e8 6b 17 4b f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 53 bf 13 f6 65 8b 05 0c 12 24 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000351f560 EFLAGS: 00000206
RAX: da61b83ab7360100 RBX: 0000000000000a06 RCX: da61b83ab7360100
RDX: 0000000000000006 RSI: ffffffff8d9b77e3 RDI: 0000000000000001
RBP: ffffc9000351f5f8 R08: ffffffff8fa38a37 R09: 1ffffffff1f47146
R10: dffffc0000000000 R11: fffffbfff1f47147 R12: dffffc0000000000
R13: 1ffff11023dfa9bd R14: ffff88811efd4d80 R15: 1ffff920006a3eac
 __skb_try_recv_datagram+0x17c/0x4e0
 __unix_dgram_recvmsg+0x2d4/0xd60
 sock_recvmsg_nosec+0x186/0x1c0
 ____sys_recvmsg+0x3aa/0x460
 ___sys_recvmsg+0x1b5/0x510
 do_recvmmsg+0x307/0x770
 __x64_sys_recvmmsg+0x190/0x240
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb8938ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007ffb8a28c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007ffb895c6090 RCX: 00007ffb8938ebe9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007ffb89411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb895c6128 R14: 00007ffb895c6090 R15: 00007ffc8c20a728
 </TASK>
