============================================ WARNING: possible recursive locking detected 6.6.93-syzkaller #0 Not tainted -------------------------------------------- syz-executor401/5803 is trying to acquire lock: ffff88807da89a38 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:467 but task is already holding lock: ffff88807da89a38 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xca/0xea0 kernel/bpf/lpm_trie.c:335 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-executor401/5803: #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x439/0x740 kernel/bpf/syscall.c:200 #1: ffff88807da89a38 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xca/0xea0 kernel/bpf/lpm_trie.c:335 #2: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #2: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #2: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #2: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xfd/0x420 kernel/trace/bpf_trace.c:2363 stack backtrace: CPU: 1 PID: 5803 Comm: syz-executor401 Not tainted 6.6.93-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:467 bpf_prog_ae0c3e605f35524c+0x45/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363 trace_mm_page_alloc include/trace/events/kmem.h:177 [inline] __alloc_pages+0x429/0x460 mm/page_alloc.c:4479 alloc_slab_page+0x5d/0x170 mm/slub.c:1876 allocate_slab mm/slub.c:2023 [inline] new_slab+0x87/0x2e0 mm/slub.c:2076 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230 __slab_alloc mm/slub.c:3329 [inline] __slab_alloc_node mm/slub.c:3382 [inline] slab_alloc_node mm/slub.c:3475 [inline] __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc_node+0xa4/0x230 mm/slab_common.c:1014 kmalloc_node include/linux/slab.h:620 [inline] bpf_map_kmalloc_node+0xbc/0x1b0 kernel/bpf/syscall.c:422 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline] trie_update_elem+0x166/0xea0 kernel/bpf/lpm_trie.c:338 bpf_map_update_value+0x67c/0x740 kernel/bpf/syscall.c:201 map_update_elem+0x57b/0x700 kernel/bpf/syscall.c:1561 __sys_bpf+0x652/0x800 kernel/bpf/syscall.c:5455 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline] __se_sys_bpf kernel/bpf/syscall.c:5569 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc1d2e37e39 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:00007ffdcd01a2a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 002020786c352d25 RCX: 00007fc1d2e37e39 RDX: 0000000000000020 RSI: 00002000000002c0 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001