============================================ WARNING: possible recursive locking detected 6.1.85-syzkaller #0 Not tainted -------------------------------------------- syz-executor188/3593 is trying to acquire lock: ffff888078b20238 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:451 but task is already holding lock: ffff888073a9d238 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:451 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 4 locks held by syz-executor188/3593: #0: ffff8880233a4f78 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_cleanup_begin kernel/futex/core.c:1076 [inline] #0: ffff8880233a4f78 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_exit_release+0x30/0x1e0 kernel/futex/core.c:1128 #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2312 #2: ffff888073a9d238 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:451 #3: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #3: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2312 stack backtrace: CPU: 0 PID: 3593 Comm: syz-executor188 Not tainted 6.1.85-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:451 bpf_prog_fdee3c9a1e8a2a6e+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:989 [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:2273 [inline] bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x14c/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x935/0xc50 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x269/0x370 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xdd/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:451 bpf_prog_fdee3c9a1e8a2a6e+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:989 [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:2273 [inline] bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x12f/0x170 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:612 [inline] __mutex_lock+0x2ed/0xd80 kernel/locking/mutex.c:747 futex_cleanup_begin kernel/futex/core.c:1076 [inline] futex_exit_release+0x30/0x1e0 kernel/futex/core.c:1128 exit_mm_release+0x16/0x30 kernel/fork.c:1505 exit_mm+0xa9/0x300 kernel/exit.c:535 do_exit+0x9f6/0x26a0 kernel/exit.c:856 do_group_exit+0x202/0x2b0 kernel/exit.c:1019 get_signal+0x16f7/0x17d0 kernel/signal.c:2862 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8ec82f0919 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 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:00007f8ec82b1228 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f8ec837a328 RCX: 00007f8ec82f0919 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8ec837a328 RBP: 00007f8ec837a320 R08: 00007f8ec82b16c0 R09: 00007f8ec82b16c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8ec8347074 R13: 00646e655f6e6f69 R14: 69746e65746e6f63 R15: 00007ffc25452d18