============================================ WARNING: possible recursive locking detected 5.11.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/2982 is trying to acquire lock: ffff8881170d77b8 (&trie->lock){....}-{2:2}, at: trie_delete_elem+0x3a/0x1f0 kernel/bpf/lpm_trie.c:445 but task is already holding lock: ffff8881170d79b8 (&trie->lock){....}-{2:2}, at: trie_update_elem+0x44/0x350 kernel/bpf/lpm_trie.c:318 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-executor.0/2982: #0: ffffffff82f86d40 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value.isra.0+0x271/0x460 kernel/bpf/syscall.c:194 #1: ffff8881170d79b8 (&trie->lock){....}-{2:2}, at: trie_update_elem+0x44/0x350 kernel/bpf/lpm_trie.c:318 #2: ffffffff82f86d40 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x0/0x180 kernel/trace/bpf_trace.c:2123 stack backtrace: CPU: 0 PID: 2982 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x77/0x97 lib/dump_stack.c:120 print_deadlock_bug kernel/locking/lockdep.c:2761 [inline] check_deadlock kernel/locking/lockdep.c:2804 [inline] validate_chain kernel/locking/lockdep.c:3595 [inline] __lock_acquire.cold+0x13a/0x2b9 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5442 [inline] lock_acquire+0xbf/0x3b0 kernel/locking/lockdep.c:5407 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159 trie_delete_elem+0x3a/0x1f0 kernel/bpf/lpm_trie.c:445 ____bpf_map_delete_elem kernel/bpf/helpers.c:65 [inline] bpf_map_delete_elem+0x21/0x30 kernel/bpf/helpers.c:62 ___bpf_prog_run+0xabd/0x1450 kernel/bpf/core.c:1513 __bpf_prog_run32+0x34/0x60 kernel/bpf/core.c:1678 bpf_dispatcher_nop_func include/linux/bpf.h:651 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2085 [inline] bpf_trace_run4+0x7f/0x180 kernel/trace/bpf_trace.c:2124 trace_mm_page_alloc include/trace/events/kmem.h:193 [inline] __alloc_pages_nodemask+0x28d/0x390 mm/page_alloc.c:5023 __alloc_pages include/linux/gfp.h:511 [inline] __alloc_pages_node include/linux/gfp.h:524 [inline] alloc_pages_node include/linux/gfp.h:538 [inline] kmalloc_large_node+0x4c/0xf0 mm/slub.c:3999 __kmalloc_node+0x2f3/0x400 mm/slub.c:4015 kmalloc_node include/linux/slab.h:575 [inline] bpf_map_kmalloc_node+0x3d/0x90 kernel/bpf/syscall.c:410 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:285 [inline] trie_update_elem+0x83/0x350 kernel/bpf/lpm_trie.c:327 bpf_map_update_value.isra.0+0x2c8/0x460 kernel/bpf/syscall.c:201 map_update_elem kernel/bpf/syscall.c:1124 [inline] __do_sys_bpf+0x18a1/0x1f30 kernel/bpf/syscall.c:4370 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7ff03ce4dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff03c9cf0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007ff03cf7bf80 RCX: 00007ff03ce4dda9 RDX: 0000000000000020 RSI: 0000000020000940 RDI: 0000000000000002 RBP: 00007ff03ce9a47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007ff03cf7bf80 R15: 00007ffd5c8afbc8