====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.14/4329 is trying to acquire lock: ffff888019db2a38 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 but task is already holding lock: ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&base->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 lock_timer_base+0x123/0x270 kernel/time/timer.c:946 __mod_timer+0x117/0xd20 kernel/time/timer.c:1019 queue_delayed_work_on+0x126/0x1e0 kernel/workqueue.c:1715 queue_delayed_work include/linux/workqueue.h:527 [inline] schedule_delayed_work include/linux/workqueue.h:631 [inline] kvfree_call_rcu+0x4a9/0x7c0 kernel/rcu/tree.c:3629 rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:225 rtnl_register+0x2e/0x70 net/core/rtnetlink.c:275 ip_rt_init+0x2e0/0x3a0 net/ipv4/route.c:3803 ip_init+0xa/0x20 net/ipv4/ip_output.c:1749 inet_init+0x28b/0x3a0 net/ipv4/af_inet.c:2007 do_one_initcall+0x1ee/0x680 init/main.c:1316 do_initcall_level+0x137/0x1f0 init/main.c:1389 do_initcalls+0x4b/0x90 init/main.c:1405 kernel_init_freeable+0x3ce/0x560 init/main.c:1629 kernel_init+0x19/0x1b0 init/main.c:1520 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #1 (krc.lock){....}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:3203 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3510 [inline] kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3601 trie_update_elem+0x86e/0xc50 kernel/bpf/lpm_trie.c:396 bpf_map_update_value+0x57d/0x650 kernel/bpf/syscall.c:223 generic_map_update_batch+0x525/0x7c0 kernel/bpf/syscall.c:1430 bpf_map_do_batch+0x466/0x600 kernel/bpf/syscall.c:-1 __sys_bpf+0x601/0x670 kernel/bpf/syscall.c:-1 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&trie->lock){..-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __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+0x90/0x710 kernel/bpf/lpm_trie.c:467 bpf_prog_5186c38a4019a4cb+0x42/0xe84 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x394/0x520 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0x8e1/0xd20 kernel/time/timer.c:1062 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x142/0x180 net/802/mrp.c:611 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 smp_call_function_many_cond+0xa89/0xd70 kernel/smp.c:904 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1442 [inline] text_poke_bp_batch+0x533/0x7c0 arch/x86/kernel/alternative.c:1704 text_poke_bp+0xd2/0x150 arch/x86/kernel/alternative.c:1879 __static_call_transform+0x318/0x500 arch/x86/kernel/static_call.c:111 arch_static_call_transform+0xa0/0x250 arch/x86/kernel/static_call.c:157 __static_call_update+0xdd/0x5b0 kernel/static_call_inline.c:136 tracepoint_update_call kernel/tracepoint.c:317 [inline] tracepoint_add_func+0x6bf/0x9a0 kernel/tracepoint.c:365 tracepoint_probe_register_prio_may_exist+0x5c/0x90 kernel/tracepoint.c:482 bpf_raw_tracepoint_open+0x69d/0x780 kernel/bpf/syscall.c:3119 __sys_bpf+0x48b/0x670 kernel/bpf/syscall.c:4699 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &trie->lock --> krc.lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(krc.lock); lock(&base->lock); lock(&trie->lock); *** DEADLOCK *** 8 locks held by syz.2.14/4329: #0: ffffffff8c15c488 (tracepoints_mutex){+.+.}-{3:3}, at: tracepoint_probe_register_prio_may_exist+0x40/0x90 kernel/tracepoint.c:478 #1: ffffffff8bfbae90 (cpu_hotplug_lock){++++}-{0:0}, at: __static_call_update+0x88/0x5b0 kernel/static_call_inline.c:128 #2: ffffffff8c1a1c48 (static_call_mutex){+.+.}-{3:3}, at: static_call_lock kernel/static_call_inline.c:25 [inline] #2: ffffffff8c1a1c48 (static_call_mutex){+.+.}-{3:3}, at: __static_call_update+0x96/0x5b0 kernel/static_call_inline.c:129 #3: ffffffff8bfd1f48 (text_mutex){+.+.}-{3:3}, at: arch_static_call_transform+0x2e/0x250 arch/x86/kernel/static_call.c:153 #4: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #4: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441 #5: ffff8880614bdcc8 (&app->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline] #5: ffff8880614bdcc8 (&app->lock){+.-.}-{2:2}, at: mrp_join_timer+0xd2/0x180 net/802/mrp.c:609 #6: ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946 #7: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312 stack backtrace: CPU: 1 PID: 4329 Comm: syz.2.14 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __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+0x90/0x710 kernel/bpf/lpm_trie.c:467 bpf_prog_5186c38a4019a4cb+0x42/0xe84 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x394/0x520 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0x8e1/0xd20 kernel/time/timer.c:1062 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x142/0x180 net/802/mrp.c:611 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:smp_call_function_many_cond+0xa89/0xd70 kernel/smp.c:904 Code: e8 1c 47 0b 00 0f 0b e9 73 f9 ff ff e8 10 47 0b 00 e8 4b 62 35 08 48 85 db 0f 84 97 fe ff ff e8 fd 46 0b 00 fb 44 3b 7c 24 64 <0f> 92 c0 84 44 24 3c 75 0a e8 e9 46 0b 00 e9 95 01 00 00 49 8d 75 RSP: 0018:ffffc900023a7600 EFLAGS: 00000293 RAX: ffffffff816c8513 RBX: 0000000000000200 RCX: 0000000000080000 RDX: ffffc9000f1da000 RSI: 00000000000002ca RDI: 00000000000002cb RBP: ffffc900023a7740 R08: dffffc0000000000 R09: fffffbfff1ff5419 R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: 0000000000000000 R13: ffff8880b913b3c0 R14: 0000000000000000 R15: 0000000000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1442 [inline] text_poke_bp_batch+0x533/0x7c0 arch/x86/kernel/alternative.c:1704 text_poke_bp+0xd2/0x150 arch/x86/kernel/alternative.c:1879 __static_call_transform+0x318/0x500 arch/x86/kernel/static_call.c:111 arch_static_call_transform+0xa0/0x250 arch/x86/kernel/static_call.c:157 __static_call_update+0xdd/0x5b0 kernel/static_call_inline.c:136 tracepoint_update_call kernel/tracepoint.c:317 [inline] tracepoint_add_func+0x6bf/0x9a0 kernel/tracepoint.c:365 tracepoint_probe_register_prio_may_exist+0x5c/0x90 kernel/tracepoint.c:482 bpf_raw_tracepoint_open+0x69d/0x780 kernel/bpf/syscall.c:3119 __sys_bpf+0x48b/0x670 kernel/bpf/syscall.c:4699 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fe840518749 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:00007fe83e75e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fe84076f090 RCX: 00007fe840518749 RDX: 0000000000000010 RSI: 0000200000000040 RDI: 0000000000000011 RBP: 00007fe84059cf91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe84076f128 R14: 00007fe84076f090 R15: 00007ffd926ed488 ---------------- Code disassembly (best guess): 0: e8 1c 47 0b 00 call 0xb4721 5: 0f 0b ud2 7: e9 73 f9 ff ff jmp 0xfffff97f c: e8 10 47 0b 00 call 0xb4721 11: e8 4b 62 35 08 call 0x8356261 16: 48 85 db test %rbx,%rbx 19: 0f 84 97 fe ff ff je 0xfffffeb6 1f: e8 fd 46 0b 00 call 0xb4721 24: fb sti 25: 44 3b 7c 24 64 cmp 0x64(%rsp),%r15d * 2a: 0f 92 c0 setb %al <-- trapping instruction 2d: 84 44 24 3c test %al,0x3c(%rsp) 31: 75 0a jne 0x3d 33: e8 e9 46 0b 00 call 0xb4721 38: e9 95 01 00 00 jmp 0x1d2 3d: 49 rex.WB 3e: 8d .byte 0x8d 3f: 75 .byte 0x75