INFO: task syz.5.159:6849 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.159       state:D stack:17448 pid:6849  tgid:6846  ppid:6454   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: 0033:0x7f7c3018ec29
RSP: 002b:00007f7c3102c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7c303d5fa0 RCX: 00007f7c3018ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7c303d5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c303d6038 R14: 00007f7c303d5fa0 R15: 00007ffcf4429398
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5676:
 #0: ffff888028e8f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by udevd/6014:
 #0: ffff8880210b0358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.5.159/6849:
 #0: ffff8880210b0358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340

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

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+0x439/0x7d0
 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: 5850 Comm: syz-executor 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_release+0x2b5/0x3e0
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 0b 5f 03 11 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003347998 EFLAGS: 00000206
RAX: 580f7e57a6ed6700 RBX: 0000000000000202 RCX: 580f7e57a6ed6700
RDX: 0000000000000000 RSI: ffffffff8dba996e RDI: ffffffff8be33f80
RBP: ffff88810511e130 R08: 0000000000000000 R09: ffffffff848500ca
R10: dffffc0000000000 R11: ffffed10036dc701 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8e13a0e0 R15: ffff88810511d640
FS:  000055558254d500(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056335af6c7e8 CR3: 00000000275c4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 aa_file_perm+0x448/0x1550
 common_file_perm+0x1a9/0x230
 security_file_permission+0x91/0x290
 rw_verify_area+0xbb/0x4d0
 vfs_read+0x154/0xa30
 ksys_read+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2cc9d8d5fd
Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b5 e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d 61 af 21 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
RSP: 002b:00007fff9d9e59d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2cc9d8d5fd
RDX: 0000000000000004 RSI: 00007fff9d9e59ec RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000033232dd6 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff9d9e5e00
R13: 0000000000000004 R14: 00007fff9d9e59ec R15: 00007fff9d9e5a80
 </TASK>
