============================================ WARNING: possible recursive locking detected 6.1.138-syzkaller #0 Not tainted -------------------------------------------- syz.1.786/7875 is trying to acquire lock: ffff88802a89f238 (&trie->lock){....}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467 but task is already holding lock: ffff88802a898238 (&trie->lock){....}-{2:2}, at: trie_update_elem+0xc4/0xe90 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.1.786/7875: #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x379/0x670 kernel/bpf/syscall.c:225 #1: ffff88802a898238 (&trie->lock){....}-{2:2}, at: trie_update_elem+0xc4/0xe90 kernel/bpf/lpm_trie.c:335 #2: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #2: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xf9/0x420 kernel/trace/bpf_trace.c:2326 stack backtrace: CPU: 0 PID: 7875 Comm: syz.1.786 Not tainted 6.1.138-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __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+0x90/0x690 kernel/bpf/lpm_trie.c:467 bpf_prog_1db1603a7cfa36fb+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run4+0x1f5/0x420 kernel/trace/bpf_trace.c:2326 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:177 trace_mm_page_alloc include/trace/events/kmem.h:177 [inline] __alloc_pages+0x49c/0x4e0 mm/page_alloc.c:5628 __alloc_pages_node include/linux/gfp.h:237 [inline] alloc_pages_node include/linux/gfp.h:260 [inline] __kmalloc_large_node+0x8c/0x1e0 mm/slab_common.c:1077 __do_kmalloc_node mm/slab_common.c:924 [inline] __kmalloc_node+0x10e/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] bpf_map_kmalloc_node+0xb8/0x1a0 kernel/bpf/syscall.c:452 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline] trie_update_elem+0x160/0xe90 kernel/bpf/lpm_trie.c:338 bpf_map_update_value+0x5a0/0x670 kernel/bpf/syscall.c:226 map_update_elem+0x4d7/0x680 kernel/bpf/syscall.c:1466 __sys_bpf+0x454/0x6d0 kernel/bpf/syscall.c:5008 __do_sys_bpf kernel/bpf/syscall.c:5124 [inline] __se_sys_bpf kernel/bpf/syscall.c:5122 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f32c4d8e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f32c5b35038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f32c4fb5fa0 RCX: 00007f32c4d8e969 RDX: 0000000000000020 RSI: 0000200000000080 RDI: 0000000000000002 RBP: 00007f32c4e10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f32c4fb5fa0 R15: 00007ffcc4da2b58