======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.11696/9141 is trying to acquire lock:
ffffffff974e4618 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:1034 [inline]
ffffffff974e4618 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x9e/0x520 lib/debugobjects.c:1075

but task is already holding lock:
ffff88802fcdd238 (&trie->lock){....}-{2:2}, at: trie_update_elem+0xc4/0xd60 kernel/bpf/lpm_trie.c:335

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&trie->lock){....}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162
       trie_delete_elem+0x94/0x630 kernel/bpf/lpm_trie.c:466
       0xffffffffa0000a5e
       bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline]
       __bpf_prog_run include/linux/filter.h:617 [inline]
       bpf_prog_run include/linux/filter.h:624 [inline]
       bpf_prog_run_array include/linux/bpf.h:1994 [inline]
       trace_call_bpf+0x333/0x6c0 kernel/trace/bpf_trace.c:143
       perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10287
       perf_trace_lock_acquire+0x342/0x400 include/trace/events/lock.h:24
       trace_lock_acquire include/trace/events/lock.h:24 [inline]
       lock_acquire+0x3ef/0x420 kernel/locking/lockdep.c:5725
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __free_object+0x3fe/0xa70 lib/debugobjects.c:371
       __debug_check_no_obj_freed lib/debugobjects.c:1050 [inline]
       debug_check_no_obj_freed+0x10e/0x520 lib/debugobjects.c:1075
       slab_free_hook mm/slub.c:1786 [inline]
       slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
       slab_free mm/slub.c:3830 [inline]
       kmem_cache_free_bulk+0x357/0x470 mm/slub.c:3948
       kfree_bulk include/linux/slab.h:517 [inline]
       kvfree_rcu_bulk+0x1eb/0x470 kernel/rcu/tree.c:3032
       kvfree_rcu_drain_ready kernel/rcu/tree.c:3216 [inline]
       kfree_rcu_monitor+0x7d3/0xf70 kernel/rcu/tree.c:3234
       process_one_work kernel/workqueue.c:2653 [inline]
       process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
       worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
       kthread+0x2fa/0x390 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

-> #0 (&obj_hash[i].lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162
       __debug_check_no_obj_freed lib/debugobjects.c:1034 [inline]
       debug_check_no_obj_freed+0x9e/0x520 lib/debugobjects.c:1075
       slab_free_hook mm/slub.c:1786 [inline]
       slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
       slab_free mm/slub.c:3830 [inline]
       __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
       trie_update_elem+0x783/0xd60 kernel/bpf/lpm_trie.c:443
       bpf_map_update_value+0x64b/0x710 kernel/bpf/syscall.c:203
       generic_map_update_batch+0x5de/0x800 kernel/bpf/syscall.c:1800
       bpf_map_do_batch+0x3f2/0x600 kernel/bpf/syscall.c:5011
       __sys_bpf+0x381/0x890 kernel/bpf/syscall.c:-1
       __do_sys_bpf kernel/bpf/syscall.c:5582 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5580 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5580
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(&obj_hash[i].lock);
                               lock(&trie->lock);
  lock(&obj_hash[i].lock);

 *** DEADLOCK ***

2 locks held by syz.2.11696/9141:
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x408/0x710 kernel/bpf/syscall.c:202
 #1: ffff88802fcdd238 (&trie->lock){....}-{2:2}, at: trie_update_elem+0xc4/0xd60 kernel/bpf/lpm_trie.c:335

stack backtrace:
CPU: 1 PID: 9141 Comm: syz.2.11696 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162
 __debug_check_no_obj_freed lib/debugobjects.c:1034 [inline]
 debug_check_no_obj_freed+0x9e/0x520 lib/debugobjects.c:1075
 slab_free_hook mm/slub.c:1786 [inline]
 slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 trie_update_elem+0x783/0xd60 kernel/bpf/lpm_trie.c:443
 bpf_map_update_value+0x64b/0x710 kernel/bpf/syscall.c:203
 generic_map_update_batch+0x5de/0x800 kernel/bpf/syscall.c:1800
 bpf_map_do_batch+0x3f2/0x600 kernel/bpf/syscall.c:5011
 __sys_bpf+0x381/0x890 kernel/bpf/syscall.c:-1
 __do_sys_bpf kernel/bpf/syscall.c:5582 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5580 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5580
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f525f19de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5260081028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f525f425fa0 RCX: 00007f525f19de99
RDX: 0000000000000038 RSI: 0000200000000240 RDI: 000000000000001a
RBP: 00007f525f233eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f525f426038 R14: 00007f525f425fa0 R15: 00007ffda2457f18
 </TASK>