INFO: task syz.0.19:5065 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.19        state:D stack:26240 pid: 5065 ppid:  4855 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x97/0x280 kernel/time/timer.c:1890
 do_wait_for_common+0x29a/0x440 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 kthread_stop+0x16e/0x540 kernel/kthread.c:666
 ext4_stop_mmpd+0x43/0xb0 fs/ext4/mmp.c:263
 ext4_fill_super+0x660b/0x9a60 fs/ext4/super.c:5088
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f553b11190a
RSP: 002b:00007f553a380e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f553a380ef0 RCX: 00007f553b11190a
RDX: 0000400000000040 RSI: 0000400000000000 RDI: 00007f553a380eb0
RBP: 0000400000000040 R08: 00007f553a380ef0 R09: 0000000003010008
R10: 0000000003010008 R11: 0000000000000246 R12: 0000400000000000
R13: 00007f553a380eb0 R14: 0000000000000538 R15: 0000400000000340
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3945:
 #0: ffff88802b078098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
3 locks held by kworker/u4:4/4243:
 #0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffffc90002f2fd00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880b90280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
1 lock held by syz.0.19/5065:
 #0: ffff88807bd1c0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.1.22/5097:
 #0: ffff88802b4b40e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.2.29/5137:
 #0: ffff88807d7720e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.3.31/5163:
 #0: ffff88801d6300e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.4.44/5233:
 #0: ffff88802a2960e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.5.45/5262:
 #0: ffff88802aca20e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.6.49/5300:
 #0: ffff8880246880e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.7.50/5329:
 #0: ffff888056f0c0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.8.55/5375:
 #0: ffff8880563c40e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz.9.60/5414:
 #0: ffff88802b8ae0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4243 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_preemption_disabled+0x13/0x110 lib/smp_processor_id.c:13
Code: 59 76 5b c3 00 00 cc 48 c7 c7 20 a8 59 8a 48 c7 c6 60 a8 59 8a eb 00 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 <48> 89 44 24 08 65 8b 05 49 b7 58 76 65 8b 0d b2 11 59 76 f7 c1 ff
RSP: 0018:ffffc90002f2f9a8 EFLAGS: 00000282
RAX: 6f4dbca8373b5200 RBX: 0000000000000000 RCX: ffffffff815c7aa9
RDX: 0000000000000000 RSI: ffffffff8a59a860 RDI: ffffffff8a59a820
RBP: ffffc90002f2fb20 R08: dffffc0000000000 R09: fffffbfff1ad334e
R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: ffff88807b7043d8
R13: dffffc0000000000 R14: ffffffff897eed36 R15: 1ffff920005e5f4c
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b4ab9f9a38 CR3: 0000000022921000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline]
 rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123
 trace_lock_release include/trace/events/lock.h:58 [inline]
 lock_release+0xba/0x870 kernel/locking/lockdep.c:5634
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline]
 _raw_spin_unlock_bh+0x17/0x30 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:409 [inline]
 batadv_nc_purge_paths+0x316/0x3b0 net/batman-adv/network-coding.c:475
 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>