============================================
WARNING: possible recursive locking detected
6.11.0-rc3-syzkaller-00482-ga99ef548bba0 #0 Not tainted
--------------------------------------------
kworker/0:1/9 is trying to acquire lock:
ffff8880b932a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051

but task is already holding lock:
ffff8880b922a718 (&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

5 locks held by kworker/0:1/9:
 #0: ffff888015880948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff888015880948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc900000e7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 #1: ffffc900000e7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffff88807ea78240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x2d1/0x4130 drivers/net/netdevsim/fib.c:1489
 #3: ffff8880b922a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
 #4: ffffffff8f04dc80 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool+0x80/0x9b0 lib/debugobjects.c:615

stack backtrace:
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.11.0-rc3-syzkaller-00482-ga99ef548bba0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: events nsim_fib_event_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 check_deadlock kernel/locking/lockdep.c:3061 [inline]
 validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3855
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 __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:2554
 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:1013 [inline]
 debug_check_no_obj_freed+0x14a/0x580 lib/debugobjects.c:1020
 free_pages_prepare mm/page_alloc.c:1101 [inline]
 free_unref_page+0x38a/0xea0 mm/page_alloc.c:2612
 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:3988 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044
 fill_pool lib/debugobjects.c:169 [inline]
 debug_objects_fill_pool+0x70e/0x9b0 lib/debugobjects.c:616
 debug_object_activate+0x135/0x510 lib/debugobjects.c:705
 debug_timer_activate kernel/time/timer.c:836 [inline]
 __mod_timer+0x89d/0xeb0 kernel/time/timer.c:1171
 schedule_timeout+0x1b9/0x310 kernel/time/timer.c:2580
 schedule_timeout_uninterruptible kernel/time/timer.c:2615 [inline]
 msleep+0xa2/0xe0 kernel/time/timer.c:2736
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x2e2c/0x4130 drivers/net/netdevsim/fib.c:1492
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
 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>