============================================
WARNING: possible recursive locking detected
6.10.0-rc6-syzkaller-00195-gd7c199e77ef2 #0 Not tainted
--------------------------------------------
kworker/u8:3/50 is trying to acquire lock:
ffff8880b952a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051

but task is already holding lock:
ffff8880b942a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&base->lock);
  lock(&base->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

6 locks held by kworker/u8:3/50:
 #0: ffff88802a978948 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline]
 #0: ffff88802a978948 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329
 #1: ffffc90000ba7d00 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline]
 #1: ffffc90000ba7d00 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329
 #2: ffff8880631d9910 (&hard_iface->bat_iv.ogm_buff_mutex){+.+.}-{3:3}, at: batadv_iv_ogm_schedule+0xde/0x1090 net/batman-adv/bat_iv_ogm.c:867
 #3: ffff888064344d38 (&bat_priv->forw_bat_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #3: ffff888064344d38 (&bat_priv->forw_bat_list_lock){+...}-{2:2}, at: batadv_forw_packet_queue+0x33/0x270 net/batman-adv/send.c:673
 #4: ffff8880b942a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
 #5: ffffffff8ea40b40 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool+0x80/0x9b0 lib/debugobjects.c:614

stack backtrace:
CPU: 0 PID: 50 Comm: kworker/u8:3 Not tainted 6.10.0-rc6-syzkaller-00195-gd7c199e77ef2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3856
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
 __mod_timer+0x1ca/0xeb0 kernel/time/timer.c:1132
 queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2573
 queue_delayed_work include/linux/workqueue.h:636 [inline]
 schedule_delayed_work include/linux/workqueue.h:776 [inline]
 __debug_check_no_obj_freed lib/debugobjects.c:1012 [inline]
 debug_check_no_obj_freed+0x14a/0x580 lib/debugobjects.c:1019
 free_pages_prepare mm/page_alloc.c:1100 [inline]
 free_unref_page+0x38a/0xea0 mm/page_alloc.c:2588
 stack_depot_save_flags+0x6f6/0x830 lib/stackdepot.c:666
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x51/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3940 [inline]
 slab_alloc_node mm/slub.c:4002 [inline]
 kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4009
 fill_pool lib/debugobjects.c:168 [inline]
 debug_objects_fill_pool+0x70e/0x9b0 lib/debugobjects.c:615
 debug_object_activate+0x135/0x510 lib/debugobjects.c:704
 debug_timer_activate kernel/time/timer.c:836 [inline]
 __mod_timer+0x89d/0xeb0 kernel/time/timer.c:1171
 queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2573
 queue_delayed_work include/linux/workqueue.h:636 [inline]
 batadv_forw_packet_queue+0x22b/0x270 net/batman-adv/send.c:690
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:833 [inline]
 batadv_iv_ogm_schedule+0x85b/0x1090 net/batman-adv/bat_iv_ogm.c:868
 batadv_iv_send_outstanding_bat_ogm_packet+0x6fe/0x810 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>