====================================================== WARNING: possible circular locking dependency detected 6.6.102-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.939/9392 is trying to acquire lock: ffff88802dc37a38 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:467 but task is already holding lock: ffffffff97124808 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:979 [inline] ffffffff97124808 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x13a/0x540 lib/debugobjects.c:1020 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&obj_hash[i].lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:979 [inline] debug_check_no_obj_freed+0x13a/0x540 lib/debugobjects.c:1020 slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3829 trie_update_elem+0x6d1/0xea0 kernel/bpf/lpm_trie.c:444 bpf_map_update_value+0x660/0x720 kernel/bpf/syscall.c:201 generic_map_update_batch+0x5e0/0x810 kernel/bpf/syscall.c:1794 bpf_map_do_batch+0x3d7/0x610 kernel/bpf/syscall.c:5001 __sys_bpf+0x31b/0x800 kernel/bpf/syscall.c:-1 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline] __se_sys_bpf kernel/bpf/syscall.c:5569 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&trie->lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:467 bpf_prog_ae0c3e605f35524c+0x45/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122 trace_contention_end+0xe6/0x110 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7ec/0x9d0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:979 [inline] debug_check_no_obj_freed+0x13a/0x540 lib/debugobjects.c:1020 slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] kmem_cache_free+0xf8/0x280 mm/slub.c:3838 rcu_do_batch kernel/rcu/tree.c:2194 [inline] rcu_core+0xcc4/0x1720 kernel/rcu/tree.c:2467 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 perf_trace_buf_alloc+0xb/0x290 kernel/trace/trace_event_perf.c:399 perf_trace_lock_acquire+0x19c/0x3e0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x3e2/0x410 kernel/locking/lockdep.c:5725 down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573 kernfs_add_one+0x9e/0x6b0 fs/kernfs/dir.c:778 __kernfs_create_file+0x237/0x2e0 fs/kernfs/file.c:1079 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:294 sysfs_merge_group+0x178/0x310 fs/sysfs/group.c:346 dpm_sysfs_add+0xd2/0x270 drivers/base/power/sysfs.c:707 device_add+0x56a/0xc20 drivers/base/core.c:3643 netdev_register_kobject+0x17a/0x310 net/core/net-sysfs.c:2042 register_netdevice+0x128f/0x1ae0 net/core/dev.c:10268 register_netdev+0x3b/0x50 net/core/dev.c:10400 sit_init_net+0x1fb/0x550 net/ipv6/sit.c:1861 ops_init+0x397/0x640 net/core/net_namespace.c:139 setup_net+0x3a5/0xa00 net/core/net_namespace.c:343 copy_net_ns+0x36d/0x5e0 net/core/net_namespace.c:520 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110 copy_namespaces+0x430/0x4a0 kernel/nsproxy.c:179 copy_process+0x1700/0x3d70 kernel/fork.c:2509 kernel_clone+0x21b/0x840 kernel/fork.c:2914 __do_sys_clone kernel/fork.c:3057 [inline] __se_sys_clone kernel/fork.c:3041 [inline] __x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&obj_hash[i].lock); lock(&trie->lock); lock(&obj_hash[i].lock); lock(&trie->lock); *** DEADLOCK *** 5 locks held by syz.1.939/9392: #0: ffffffff8dfaec50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x351/0x5e0 net/core/net_namespace.c:516 #1: ffffffff8dfbba48 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x13/0x50 net/core/dev.c:10398 #2: ffffffff8cd2fd00 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #2: ffffffff8cd2fd00 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2188 [inline] #2: ffffffff8cd2fd00 (rcu_callback){....}-{0:0}, at: rcu_core+0xc51/0x1720 kernel/rcu/tree.c:2467 #3: ffffffff97124808 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:979 [inline] #3: ffffffff97124808 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x13a/0x540 lib/debugobjects.c:1020 #4: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #4: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #4: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #4: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xde/0x3c0 kernel/trace/bpf_trace.c:2361 stack backtrace: CPU: 1 PID: 9392 Comm: syz.1.939 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:467 bpf_prog_ae0c3e605f35524c+0x45/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122 trace_contention_end+0xe6/0x110 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7ec/0x9d0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:979 [inline] debug_check_no_obj_freed+0x13a/0x540 lib/debugobjects.c:1020 slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] kmem_cache_free+0xf8/0x280 mm/slub.c:3838 rcu_do_batch kernel/rcu/tree.c:2194 [inline] rcu_core+0xcc4/0x1720 kernel/rcu/tree.c:2467 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:perf_trace_buf_alloc+0xb/0x290 kernel/trace/trace_event_perf.c:399 Code: 48 89 03 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 1c df f7 ff 43 80 7c 25 00 00 75 d3 eb d9 66 90 f3 0f 1e fa 55 41 57 41 56 41 55 <41> 54 53 50 49 89 d7 49 89 f6 89 fb e8 f4 de f7 ff bf 00 20 00 00 RSP: 0018:ffffc9000491eff8 EFLAGS: 00000203 RAX: 1ffffffff197f5c6 RBX: ffffffff8c7d1a38 RCX: ffffe8ffffd2a2e0 RDX: ffffc9000491f0a0 RSI: ffffc9000491f080 RDI: 000000000000002c RBP: ffffc9000491f120 R08: 0000000000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1c95106 R12: dffffc0000000000 R13: 0000000000000013 R14: 000000000000002c R15: 1ffff92000923e0c perf_trace_lock_acquire+0x19c/0x3e0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x3e2/0x410 kernel/locking/lockdep.c:5725 down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573 kernfs_add_one+0x9e/0x6b0 fs/kernfs/dir.c:778 __kernfs_create_file+0x237/0x2e0 fs/kernfs/file.c:1079 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:294 sysfs_merge_group+0x178/0x310 fs/sysfs/group.c:346 dpm_sysfs_add+0xd2/0x270 drivers/base/power/sysfs.c:707 device_add+0x56a/0xc20 drivers/base/core.c:3643 netdev_register_kobject+0x17a/0x310 net/core/net-sysfs.c:2042 register_netdevice+0x128f/0x1ae0 net/core/dev.c:10268 register_netdev+0x3b/0x50 net/core/dev.c:10400 sit_init_net+0x1fb/0x550 net/ipv6/sit.c:1861 ops_init+0x397/0x640 net/core/net_namespace.c:139 setup_net+0x3a5/0xa00 net/core/net_namespace.c:343 copy_net_ns+0x36d/0x5e0 net/core/net_namespace.c:520 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110 copy_namespaces+0x430/0x4a0 kernel/nsproxy.c:179 copy_process+0x1700/0x3d70 kernel/fork.c:2509 kernel_clone+0x21b/0x840 kernel/fork.c:2914 __do_sys_clone kernel/fork.c:3057 [inline] __se_sys_clone kernel/fork.c:3041 [inline] __x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f306338ebe9 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:00007f306423afe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f30635b5fa0 RCX: 00007f306338ebe9 RDX: 00002000000001c0 RSI: 0000200000000500 RDI: 0000000040100000 RBP: 00007f3063411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f30635b6038 R14: 00007f30635b5fa0 R15: 00007ffe9b335478 ---------------- Code disassembly (best guess): 0: 48 89 03 mov %rax,(%rbx) 3: 5b pop %rbx 4: 41 5c pop %r12 6: 41 5d pop %r13 8: 41 5e pop %r14 a: 41 5f pop %r15 c: 5d pop %rbp d: c3 ret e: e8 1c df f7 ff call 0xfff7df2f 13: 43 80 7c 25 00 00 cmpb $0x0,0x0(%r13,%r12,1) 19: 75 d3 jne 0xffffffee 1b: eb d9 jmp 0xfffffff6 1d: 66 90 xchg %ax,%ax 1f: f3 0f 1e fa endbr64 23: 55 push %rbp 24: 41 57 push %r15 26: 41 56 push %r14 28: 41 55 push %r13 * 2a: 41 54 push %r12 <-- trapping instruction 2c: 53 push %rbx 2d: 50 push %rax 2e: 49 89 d7 mov %rdx,%r15 31: 49 89 f6 mov %rsi,%r14 34: 89 fb mov %edi,%ebx 36: e8 f4 de f7 ff call 0xfff7df2f 3b: bf 00 20 00 00 mov $0x2000,%edi