====================================================== WARNING: possible circular locking dependency detected 5.15.185-syzkaller #0 Not tainted ------------------------------------------------------ syz.2.37/4355 is trying to acquire lock: ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline] ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline] ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597 but task is already holding lock: ffff888022a0c5b8 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&trie->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 trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 bpf_prog_1db1603a7cfa36fb+0x5ae/0xc0c bpf_dispatcher_nop_func include/linux/bpf.h:790 [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_run2+0x15b/0x2d0 kernel/trace/bpf_trace.c:1915 trace_hrtimer_start include/trace/events/timer.h:199 [inline] debug_activate kernel/time/hrtimer.c:466 [inline] enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1074 __run_hrtimer kernel/time/hrtimer.c:1707 [inline] __hrtimer_run_queues+0x65a/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 consume_obj_stock mm/memcontrol.c:3154 [inline] obj_cgroup_charge+0xef/0x310 mm/memcontrol.c:3267 pcpu_memcg_pre_alloc_hook mm/percpu.c:1638 [inline] pcpu_alloc+0x204/0x1770 mm/percpu.c:1763 bpf_map_alloc_percpu+0xc5/0x150 kernel/bpf/syscall.c:455 bpf_array_alloc_percpu kernel/bpf/arraymap.c:37 [inline] array_map_alloc+0x370/0x6f0 kernel/bpf/arraymap.c:153 find_and_alloc_map kernel/bpf/syscall.c:127 [inline] map_create+0x46e/0x2140 kernel/bpf/syscall.c:880 __sys_bpf+0x2a4/0x670 kernel/bpf/syscall.c:4633 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline] __se_sys_bpf kernel/bpf/syscall.c:4753 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753 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 -> #1 (hrtimer_bases.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_hrtimer_base kernel/time/hrtimer.c:168 [inline] hrtimer_start_range_ns+0xff/0xc20 kernel/time/hrtimer.c:1289 hrtimer_start include/linux/hrtimer.h:420 [inline] run_page_cache_worker kernel/rcu/tree.c:3488 [inline] kvfree_call_rcu+0x60d/0x7c0 kernel/rcu/tree.c:3599 rtnl_register_internal+0x44e/0x540 net/core/rtnetlink.c:223 rtnl_register+0x2e/0x70 net/core/rtnetlink.c:273 ip_rt_init+0x2e0/0x3a0 net/ipv4/route.c:3791 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:1302 do_initcall_level+0x137/0x1f0 init/main.c:1375 do_initcalls+0x4b/0x90 init/main.c:1391 kernel_init_freeable+0x3ce/0x560 init/main.c:1615 kernel_init+0x19/0x1b0 init/main.c:1506 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 (krc.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 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:3199 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline] kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597 trie_delete_elem+0x58c/0x710 kernel/bpf/lpm_trie.c:-1 bpf_prog_1db1603a7cfa36fb+0x3d/0xc0c bpf_dispatcher_nop_func include/linux/bpf.h:790 [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_run1+0x153/0x2d0 kernel/trace/bpf_trace.c:1914 trace_qdisc_reset include/trace/events/qdisc.h:77 [inline] qdisc_reset+0x49d/0x500 net/sched/sch_generic.c:974 qdisc_reset_all_tx_gt include/net/sch_generic.h:750 [inline] netif_set_real_num_tx_queues+0x5fa/0x840 net/core/dev.c:2985 tun_set_real_num_queues drivers/net/tun.c:590 [inline] __tun_detach+0xbd2/0x1500 drivers/net/tun.c:674 tun_set_queue drivers/net/tun.c:2941 [inline] __tun_chr_ioctl+0xaa5/0x1e70 drivers/net/tun.c:3045 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 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: krc.lock --> hrtimer_bases.lock --> &trie->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&trie->lock); lock(hrtimer_bases.lock); lock(&trie->lock); lock(krc.lock); *** DEADLOCK *** 4 locks held by syz.2.37/4355: #0: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: tun_set_queue drivers/net/tun.c:2923 [inline] #0: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x361/0x1e70 drivers/net/tun.c:3045 #1: ffffffff8d269a88 (noop_qdisc.q.lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] #1: ffffffff8d269a88 (noop_qdisc.q.lock){+.-.}-{2:2}, at: qdisc_reset_all_tx_gt include/net/sch_generic.h:749 [inline] #1: ffffffff8d269a88 (noop_qdisc.q.lock){+.-.}-{2:2}, at: netif_set_real_num_tx_queues+0x5f2/0x840 net/core/dev.c:2985 #2: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 #3: ffff888022a0c5b8 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 stack backtrace: CPU: 0 PID: 4355 Comm: syz.2.37 Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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 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:3199 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline] kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597 trie_delete_elem+0x58c/0x710 kernel/bpf/lpm_trie.c:-1 bpf_prog_1db1603a7cfa36fb+0x3d/0xc0c bpf_dispatcher_nop_func include/linux/bpf.h:790 [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_run1+0x153/0x2d0 kernel/trace/bpf_trace.c:1914 trace_qdisc_reset include/trace/events/qdisc.h:77 [inline] qdisc_reset+0x49d/0x500 net/sched/sch_generic.c:974 qdisc_reset_all_tx_gt include/net/sch_generic.h:750 [inline] netif_set_real_num_tx_queues+0x5fa/0x840 net/core/dev.c:2985 tun_set_real_num_queues drivers/net/tun.c:590 [inline] __tun_detach+0xbd2/0x1500 drivers/net/tun.c:674 tun_set_queue drivers/net/tun.c:2941 [inline] __tun_chr_ioctl+0xaa5/0x1e70 drivers/net/tun.c:3045 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 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: 0033:0x7fbd56a93929 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:00007fbd548fb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fbd56cbafa0 RCX: 00007fbd56a93929 RDX: 0000200000000100 RSI: 00000000400454d9 RDI: 0000000000000007 RBP: 00007fbd56b15b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fbd56cbafa0 R15: 00007ffcf594dce8