INFO: task syz.9.1930:18050 blocked for more than 204 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1930      state:D stack:24680 pid:18050 tgid:18049 ppid:15062  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: 0033:0x7f962399c799
RSP: 002b:00007f96248c1028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f9623c15fa0 RCX: 00007f962399c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f9623c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9623c16038 R14: 00007f9623c15fa0 R15: 00007ffe83b510e8
 </TASK>
INFO: task syz.0.2189:19468 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.0.2189      state:D stack:28160 pid:19468 tgid:19466 ppid:18296  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 bdev_open+0xe0/0xd30
 blkdev_open+0x470/0x610
 do_dentry_open+0x785/0x14e0
 vfs_open+0x3b/0x340
 path_openat+0x2e08/0x3860
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x113/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feebd75cfce
RSP: 002b:00007feebe64cb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007feebe64d6c0 RCX: 00007feebd75cfce
RDX: 0000000000002c00 RSI: 00007feebe64cc00 RDI: ffffffffffffff9c
RBP: 00007feebe64cc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007feebda16128 R14: 00007feebda16090 R15: 00007ffe12d8bef8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5636:
 #0: ffff8881007090a0 (&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
6 locks held by kworker/1:4/5811:
1 lock held by udevd/11965:
 #0: ffff88816b6f0358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
4 locks held by udevd/13642:
 #0: ffff888119fc1c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10
 #1: ffff8881707c4c88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff88818a338b48 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff88823c63a518 (&pool->lock){-.-.}-{2:2}, at: __queue_work+0x80b/0x1020
1 lock held by syz.9.1930/18050:
 #0: ffff88816b6f0358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.0.2189/19468:
 #0: ffff88816b6f0358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by udevd/20091:
 #0: ffff888112ab37f0 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: kernfs_dop_revalidate+0x14a/0x5e0
3 locks held by syz.5.2910/23183:
 #0: ffff88811a886420 (sb_writers#29){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff88811954b948 (&type->i_mutex_dir_key#23){++++}-{4:4}, at: path_openat+0xb3d/0x3860
 #2: ffff88811954bdf8 (&fi->mutex){+.+.}-{4:4}, at: fuse_lock_inode+0xd3/0x120

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 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: 0 Comm: swapper/1 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:pv_native_safe_halt+0xf/0x20
Code: be 6c 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d e3 22 1b 00 fb f4 <e9> fc e9 02 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000206
RAX: 0000000000772f81 RBX: ffffffff819a8e5a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8def6fdb RDI: ffffffff8c27bf00
RBP: ffffc90000197f10 R08: ffff88823c63395b R09: 1ffff110478c672b
R10: dffffc0000000000 R11: ffffed10478c672c R12: ffffffff90119ab0
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1102c09d000
FS:  0000000000000000(0000) GS:ffff8882a9460000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005568fb133a18 CR3: 000000010df02000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x1ba/0x5d0
 cpu_startup_entry+0x43/0x60
 start_secondary+0x101/0x110
 common_startup_64+0x13e/0x147
 </TASK>
