====================================================== WARNING: possible circular locking dependency detected 6.1.135-syzkaller #0 Not tainted ------------------------------------------------------ syz.8.2844/13020 is trying to acquire lock: ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3402 but task is already holding lock: ffff8880b8e28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&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:999 __mod_timer+0x117/0xd20 kernel/time/timer.c:1072 queue_delayed_work_on+0x126/0x1e0 kernel/workqueue.c:1704 queue_delayed_work include/linux/workqueue.h:527 [inline] schedule_delayed_monitor_work kernel/rcu/tree.c:3172 [inline] kvfree_call_rcu+0x4cb/0x870 kernel/rcu/tree.c:3428 rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:260 rtnl_register+0x2e/0x70 net/core/rtnetlink.c:310 ip_rt_init+0x323/0x3b5 net/ipv4/route.c:3789 ip_init+0xa/0x14 net/ipv4/ip_output.c:1770 inet_init+0x2bd/0x3cf net/ipv4/af_inet.c:2033 do_one_initcall+0x214/0x7a0 init/main.c:1298 do_initcall_level+0x137/0x1e4 init/main.c:1371 do_initcalls+0x4b/0x8a init/main.c:1387 kernel_init_freeable+0x3fa/0x5ac init/main.c:1626 kernel_init+0x19/0x1b0 init/main.c:1514 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 (krc.lock){..-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3402 trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545 bpf_prog_41385012b43a9f2e+0x40/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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:2284 [inline] bpf_trace_run3+0x1e3/0x400 kernel/trace/bpf_trace.c:2324 __traceiter_timer_start+0x73/0xc0 include/trace/events/timer.h:53 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x411/0x5c0 kernel/time/timer.c:609 internal_add_timer kernel/time/timer.c:634 [inline] __mod_timer+0x8e1/0xd20 kernel/time/timer.c:1115 sk_reset_timer+0x1f/0xb0 net/core/sock.c:3374 tipc_sk_finish_conn+0x154/0x7e0 net/tipc/socket.c:1675 tipc_socketpair+0x250/0x470 net/tipc/socket.c:3350 __sys_socketpair+0x2ac/0x540 net/socket.c:1750 __do_sys_socketpair net/socket.c:1786 [inline] __se_sys_socketpair net/socket.c:1783 [inline] __x64_sys_socketpair+0x97/0xb0 net/socket.c:1783 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 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(&base->lock); lock(krc.lock); lock(&base->lock); lock(krc.lock); *** DEADLOCK *** 2 locks held by syz.8.2844/13020: #0: ffff8880b8e28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999 #1: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #1: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf0/0x400 kernel/trace/bpf_trace.c:2324 stack backtrace: CPU: 0 PID: 13020 Comm: syz.8.2844 Not tainted 6.1.135-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3402 trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545 bpf_prog_41385012b43a9f2e+0x40/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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:2284 [inline] bpf_trace_run3+0x1e3/0x400 kernel/trace/bpf_trace.c:2324 __traceiter_timer_start+0x73/0xc0 include/trace/events/timer.h:53 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x411/0x5c0 kernel/time/timer.c:609 internal_add_timer kernel/time/timer.c:634 [inline] __mod_timer+0x8e1/0xd20 kernel/time/timer.c:1115 sk_reset_timer+0x1f/0xb0 net/core/sock.c:3374 tipc_sk_finish_conn+0x154/0x7e0 net/tipc/socket.c:1675 tipc_socketpair+0x250/0x470 net/tipc/socket.c:3350 __sys_socketpair+0x2ac/0x540 net/socket.c:1750 __do_sys_socketpair net/socket.c:1786 [inline] __se_sys_socketpair net/socket.c:1783 [inline] __x64_sys_socketpair+0x97/0xb0 net/socket.c:1783 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6659b8e969 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:00007f665a98b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 00007f6659db5fa0 RCX: 00007f6659b8e969 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 000000000000001e RBP: 00007f6659c10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000940 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6659db5fa0 R15: 00007fff5f898038