INFO: task syz-executor.3:6900 blocked for more than 143 seconds.
      Not tainted 6.4.0-rc7-syzkaller-ge660abd551f1 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:27160 pid:6900  ppid:5069   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0x187b/0x4900 kernel/sched/core.c:6669
 schedule+0xc3/0x180 kernel/sched/core.c:6745
 perf_event_free_task+0x528/0x630 kernel/events/core.c:13162
 copy_process+0x2db8/0x4290 kernel/fork.c:2784
 kernel_clone+0x222/0x800 kernel/fork.c:2915
 __do_sys_clone kernel/fork.c:3058 [inline]
 __se_sys_clone kernel/fork.c:3042 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:3042
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x4603b9
RSP: 002b:00007f693969e198 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 00000000004603b9
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 0000002102001ff9
RBP: 00000000004a9a99 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000005 R14: 00000000004aa8e8 R15: 00007f693969e6bc
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
 #0: ffffffff8cf276f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by rcu_tasks_trace/14:
 #0: ffffffff8cf27ab0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by khungtaskd/28:
 #0: ffffffff8cf27520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/4749:
 #0: ffff8880286fd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015b02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ab/0x1db0 drivers/tty/n_tty.c:2176

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.4.0-rc7-syzkaller-ge660abd551f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x187/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xec2/0xf00 kernel/hung_task.c:379
 kthread+0x2b8/0x350 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12 Comm: kworker/u4:1 Not tainted 6.4.0-rc7-syzkaller-ge660abd551f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3759 [inline]
RIP: 0010:validate_chain+0x121/0x58f0 kernel/locking/lockdep.c:3815
Code: 04 00 00 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 60 b2 32 90 be 08 00 00 00 e8 e7 88 77 00 48 0f a3 1d af e0 c6 0e <72> 25 48 c7 c0 a0 31 b2 91 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85
RSP: 0018:ffffc90000117620 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 000000000000079b RCX: ffffffff816bd1a9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff9032b350
RBP: ffffc900001178d8 R08: dffffc0000000000 R09: fffffbfff206566b
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff888014a5e478 R14: 2fc9c0c061eac566 R15: ffff888014a5e478
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f63fbb8b580 CR3: 000000000cd30000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __lock_acquire+0x1316/0x2070 kernel/locking/lockdep.c:5088
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5705
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:355 [inline]
 batadv_nc_purge_paths+0xe8/0x3a0 net/batman-adv/network-coding.c:442
 batadv_nc_worker+0x2d3/0x5c0 net/batman-adv/network-coding.c:720
 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2405
 worker_thread+0xa63/0x1210 kernel/workqueue.c:2552
 kthread+0x2b8/0x350 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.268 msecs