INFO: task syz.2.260:7967 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.260       state:D stack:28600 pid:7967  tgid:7966  ppid:6640   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 ksys_sync+0xa0/0x170
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb77b79acb9
RSP: 002b:00007fb77c5a3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fb77ba15fa0 RCX: 00007fb77b79acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb77ba15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb77ba16038 R14: 00007fb77ba15fa0 R15: 00007ffe48cf6498
 </TASK>
INFO: task syz.2.260:7972 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.260       state:D stack:28184 pid:7972  tgid:7966  ppid:6640   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 ksys_sync+0xa0/0x170
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb77b79acb9
RSP: 002b:00007fb77c582028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fb77ba16090 RCX: 00007fb77b79acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb77ba16090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb77ba16128 R14: 00007fb77ba16090 R15: 00007ffe48cf6498
 </TASK>
INFO: task syz.2.260:7974 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.260       state:D stack:28728 pid:7974  tgid:7966  ppid:6640   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 ksys_sync+0xa0/0x170
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb77b79acb9
RSP: 002b:00007fb7799f6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fb77ba16180 RCX: 00007fb77b79acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb77ba16180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb77ba16218 R14: 00007fb77ba16180 R15: 00007ffe48cf6498
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5641:
 #0: ffff88817724f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000357b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by syz-executor/6366:
1 lock held by syz.2.260/7967:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.2.260/7972:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.2.260/7974:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.8.429/9891:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.8.429/9898:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.493/10667:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.493/10669:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.493/10677:
 #0: ffff8881a88860e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/11621:
 #0: ffffffff8e360c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by syz-executor/12305:
3 locks held by dhcpcd-run-hook/12856:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 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: 5824 Comm: kworker/u8:2 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
Workqueue: bat_events batadv_tt_purge
RIP: 0010:__lock_acquire+0x4ee/0x2cf0
Code: 49 89 ed 0f 84 cc 04 00 00 41 3b 9e 28 0b 00 00 0f 8d f5 00 00 00 4c 63 fb 4b 8d 04 bf 49 8d 1c c6 48 81 c3 50 0b 00 00 eb 1d <44> 89 e0 49 ff c7 49 63 8e 28 0b 00 00 48 83 c3 28 41 89 c4 49 39
RSP: 0018:ffffc90004d77768 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88810274a890 RCX: ffffffff937ef530
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88810274a8c0 R08: ffffffff8b494bba R09: ffff888169aa8f98
R10: dffffc0000000000 R11: fffffbfff1f9e36f R12: ffffffffffffff05
R13: ffff88810274a8c0 R14: ffff888102749d40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a991d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01ddcb4a48 CR3: 000000010bc3c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x330
 _raw_spin_lock_bh+0x36/0x50
 batadv_tt_local_purge+0x10a/0x340
 batadv_tt_purge+0x35/0x9e0
 process_scheduled_works+0xaec/0x17a0
 worker_thread+0x89f/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
