INFO: task syz.3.1229:13352 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1229      state:D stack:24448 pid:13352 tgid:13351 ppid:11574  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f6559c819
RSP: 002b:00007f1f664c9028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1f65815fa0 RCX: 00007f1f6559c819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1f65815fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1f65816038 R14: 00007f1f65815fa0 R15: 00007fff83887758
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5635:
 #0: ffff8881756660a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
1 lock held by udevd/10166:
 #0: ffff88816b3d1358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
3 locks held by kworker/1:9/11200:
1 lock held by syz.3.1229/13352:
 #0: ffff88816b3d1358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.0.1341/14255:
 #0: ffff88816b3d1358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.6.1477/15105:
 #0: ffff88816b3d1358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.5.1811/17321:
 #0: ffff88810b5fc080 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x234/0x4f0
1 lock held by syz.5.1811/17326:
2 locks held by syz.5.1811/17332:
 #0: ffff88810b5fc080 (&mm->mmap_lock){++++}-{4:4}, at: madvise_lock+0x152/0x2e0
 #1: ffffffff8e83aa28 (lock#5){+.+.}-{4:4}, at: __lru_add_drain_all+0x6b/0x5e0

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 17326 Comm: syz.5.1811 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:lock_release+0x46/0x3d0
Code: f0 2f 7a 11 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 f3 2f 7a 11 83 f8 08 0f 83 56 02 00 00 89 c0 48 0f a3 05 5c 36 70 0e 73 0d <e8> a5 f8 08 00 84 c0 0f 84 94 02 00 00 83 3d 56 69 70 0e 00 0f 84
RSP: 0018:ffffc90008abf5a8 EFLAGS: 00000097
RAX: 0000000000000001 RBX: 0000000000000a02 RCX: 0000000008abf803
RDX: ffffc90023dd8000 RSI: ffffffff8976df0c RDI: ffff8881b03b4018
RBP: ffff8881b0d15380 R08: ffff8881b0d15467 R09: 1ffff110361a2a8c
R10: dffffc0000000000 R11: ffffed10361a2a8d R12: dffffc0000000000
R13: ffffffff8976df0c R14: ffff8881b03b4018 R15: 0000000000000a02
FS:  00007fc0ec1f66c0(0000) GS:ffff8882a9462000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0ec1d5d58 CR3: 00000001112ac000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 _raw_spin_unlock_irqrestore+0x1b/0x80
 __skb_try_recv_datagram+0x17c/0x4d0
 __unix_dgram_recvmsg+0x2e3/0xd60
 sock_recvmsg_nosec+0x10c/0x140
 ____sys_recvmsg+0x3e3/0x4a0
 ___sys_recvmsg+0x215/0x590
 do_recvmmsg+0x334/0x800
 __x64_sys_recvmmsg+0x198/0x250
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0edf9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc0ec1f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc0ee216090 RCX: 00007fc0edf9c819
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fc0ee032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc0ee216128 R14: 00007fc0ee216090 R15: 00007ffd9372e168
 </TASK>
