============================================ WARNING: possible recursive locking detected 6.14.0-syzkaller-07540-geff5f16bfd87 #0 Not tainted -------------------------------------------- syz.4.1306/9824 is trying to acquire lock: ffff8880354cda68 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x96/0x6d0 kernel/bpf/lpm_trie.c:470 but task is already holding lock: ffff888034875a68 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x96/0x6d0 kernel/bpf/lpm_trie.c:470 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.4.1306/9824: #0: ffff8880b8739998 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2357 [inline] #1: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x246/0x5a0 kernel/trace/bpf_trace.c:2401 #2: ffff888034875a68 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x96/0x6d0 kernel/bpf/lpm_trie.c:470 #3: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2357 [inline] #3: ffffffff8ed3a2a0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fe/0x550 kernel/trace/bpf_trace.c:2399 stack backtrace: CPU: 1 UID: 0 PID: 9824 Comm: syz.4.1306 Not tainted 6.14.0-syzkaller-07540-geff5f16bfd87 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6d0 kernel/bpf/lpm_trie.c:470 bpf_prog_4da2e59a2499d905+0x48/0x4c bpf_dispatcher_nop_func include/linux/bpf.h:1290 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2358 [inline] bpf_trace_run2+0x2ee/0x550 kernel/trace/bpf_trace.c:2399 __bpf_trace_contention_end+0x172/0x230 include/trace/events/lock.h:122 __do_trace_contention_end include/trace/events/lock.h:122 [inline] trace_contention_end+0x118/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0xb82/0xdc0 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:572 [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+0x276/0x370 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xe4/0x130 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6d0 kernel/bpf/lpm_trie.c:470 bpf_prog_1c0c44170264bb34+0x46/0x4a bpf_dispatcher_nop_func include/linux/bpf.h:1290 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2358 [inline] bpf_trace_run4+0x336/0x5a0 kernel/trace/bpf_trace.c:2401 __bpf_trace_sched_switch+0x296/0x3d0 include/trace/events/sched.h:220 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:220 __do_trace_sched_switch include/trace/events/sched.h:220 [inline] trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x28bb/0x51f0 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 do_nanosleep+0x1a3/0x660 kernel/time/hrtimer.c:2131 hrtimer_nanosleep+0x1ee/0x410 kernel/time/hrtimer.c:2178 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1407 [inline] __se_sys_clock_nanosleep+0x360/0x3c0 kernel/time/posix-timers.c:1384 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f64c63bfa25 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8 RSP: 002b:00007ffd0df6fcf0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 00007f64c65a5fa0 RCX: 00007f64c63bfa25 RDX: 00007ffd0df6fd30 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f64c65a7ba0 R08: 0000000000000000 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000051b60 R13: 00007ffd0df6fe50 R14: ffffffffffffffff R15: 00007ffd0df6fe70