syzbot

============================================
WARNING: possible recursive locking detected
5.15.185-syzkaller #0 Not tainted
--------------------------------------------
syz-executor119/4217 is trying to acquire lock:
ffff888071f631b8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467

but task is already holding lock:
ffff88807d3865b8 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xc7/0xc50 kernel/bpf/lpm_trie.c:323

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

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

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor119/4217:
 #0: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #1: ffff88807d3865b8 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xc7/0xc50 kernel/bpf/lpm_trie.c:323
 #2: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311

stack backtrace:
CPU: 0 PID: 4217 Comm: syz-executor119 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 __lock_acquire+0x1227/0x7c60 kernel/locking/lockdep.c:-1
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
 trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
 bpf_prog_5186c38a4019a4cb+0x42/0x3fc
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run4+0x188/0x330 kernel/trace/bpf_trace.c:1917
 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201
 __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:201
 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline]
 __alloc_pages+0x449/0x470 mm/page_alloc.c:5496
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 __kmalloc_node+0x200/0x3b0 mm/slub.c:4451
 kmalloc_node include/linux/slab.h:627 [inline]
 bpf_map_kmalloc_node+0xba/0x140 kernel/bpf/syscall.c:430
 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:290 [inline]
 trie_update_elem+0x1cc/0xc50 kernel/bpf/lpm_trie.c:332
 bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221
 generic_map_update_batch+0x525/0x7c0 kernel/bpf/syscall.c:1424
 bpf_map_do_batch+0x466/0x600 kernel/bpf/syscall.c:-1
 __sys_bpf+0x601/0x670 kernel/bpf/syscall.c:-1
 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
 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: 0033:0x7f26d11a7e69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff7607de8 EFLAGS: 00000202 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000200000000440 RCX: 00007f26d11a7e69
RDX: 0000000000000038 RSI: 0000200000000240 RDI: 000000000000001a
RBP: 0000200000000240 R08: 0000000000000000 R09: 00000000000000a0
R10: 0000000000000000 R11: 0000000000000202 R12: 00002000000000c0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>