====================================================== WARNING: possible circular locking dependency detected 5.15.186-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.58/4556 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: ffff88805d2f09b8 (&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 0xffffffffa0016b91 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_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916 __traceiter_timer_start+0x73/0xc0 include/trace/events/timer.h:52 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 dsp_cmx_send+0x1ab4/0x1b30 drivers/isdn/mISDN/dsp_cmx.c:1850 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 pcpu_chunk_addr mm/percpu.c:282 [inline] pcpu_alloc+0x1006/0x1770 mm/percpu.c:1883 __percpu_counter_init+0xeb/0x290 lib/percpu_counter.c:149 nfsd_percpu_counters_init fs/nfsd/stats.c:79 [inline] nfsd_stat_counters_init+0x2c/0xa0 fs/nfsd/stats.c:108 nfsd_init_net+0x67/0x1c0 fs/nfsd/nfsctl.c:1461 ops_init+0x357/0x600 net/core/net_namespace.c:138 setup_net+0x38d/0x9f0 net/core/net_namespace.c:333 copy_net_ns+0x348/0x5b0 net/core/net_namespace.c:503 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4bc/0x890 kernel/fork.c:3175 __do_sys_unshare kernel/fork.c:3249 [inline] __se_sys_unshare kernel/fork.c:3247 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3247 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 (&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:3625 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:3795 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_f22fcc2a98ec18e8+0x3d/0x580 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_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138 trace_kmem_cache_free include/trace/events/kmem.h:138 [inline] kmem_cache_free+0x1e7/0x210 mm/slub.c:3516 adjust_va_to_fit_type mm/vmalloc.c:1336 [inline] __alloc_vmap_area mm/vmalloc.c:1452 [inline] alloc_vmap_area+0x15fa/0x1b20 mm/vmalloc.c:1543 __get_vm_area_node+0x14f/0x2d0 mm/vmalloc.c:2423 __vmalloc_node_range+0xef/0x8b0 mm/vmalloc.c:3020 __vmalloc_node mm/vmalloc.c:3080 [inline] __vmalloc+0x76/0x80 mm/vmalloc.c:3094 bpf_prog_alloc_no_stats+0x36/0x2c0 kernel/bpf/core.c:90 bpf_prog_alloc+0x1a/0x1e0 kernel/bpf/core.c:124 bpf_prog_create_from_user+0xa2/0x420 net/core/filter.c:1426 seccomp_prepare_filter kernel/seccomp.c:669 [inline] seccomp_prepare_user_filter kernel/seccomp.c:706 [inline] seccomp_set_mode_filter kernel/seccomp.c:1834 [inline] do_seccomp+0x7b6/0x1630 kernel/seccomp.c:1954 __do_sys_prctl kernel/sys.c:2380 [inline] __se_sys_prctl+0x71f/0xfd0 kernel/sys.c:2298 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 --> &base->lock --> &trie->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&trie->lock); lock(&base->lock); lock(&trie->lock); lock(krc.lock); *** DEADLOCK *** 3 locks held by syz.1.58/4556: #0: ffffffff8c1db438 (free_vmap_area_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #0: ffffffff8c1db438 (free_vmap_area_lock){+.+.}-{2:2}, at: preload_this_cpu_lock mm/vmalloc.c:1500 [inline] #0: ffffffff8c1db438 (free_vmap_area_lock){+.+.}-{2:2}, at: alloc_vmap_area+0x228/0x1b20 mm/vmalloc.c:1542 #1: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 #2: ffff88805d2f09b8 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 stack backtrace: CPU: 0 PID: 4556 Comm: syz.1.58 Not tainted 5.15.186-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_f22fcc2a98ec18e8+0x3d/0x580 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_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138 trace_kmem_cache_free include/trace/events/kmem.h:138 [inline] kmem_cache_free+0x1e7/0x210 mm/slub.c:3516 adjust_va_to_fit_type mm/vmalloc.c:1336 [inline] __alloc_vmap_area mm/vmalloc.c:1452 [inline] alloc_vmap_area+0x15fa/0x1b20 mm/vmalloc.c:1543 __get_vm_area_node+0x14f/0x2d0 mm/vmalloc.c:2423 __vmalloc_node_range+0xef/0x8b0 mm/vmalloc.c:3020 __vmalloc_node mm/vmalloc.c:3080 [inline] __vmalloc+0x76/0x80 mm/vmalloc.c:3094 bpf_prog_alloc_no_stats+0x36/0x2c0 kernel/bpf/core.c:90 bpf_prog_alloc+0x1a/0x1e0 kernel/bpf/core.c:124 bpf_prog_create_from_user+0xa2/0x420 net/core/filter.c:1426 seccomp_prepare_filter kernel/seccomp.c:669 [inline] seccomp_prepare_user_filter kernel/seccomp.c:706 [inline] seccomp_set_mode_filter kernel/seccomp.c:1834 [inline] do_seccomp+0x7b6/0x1630 kernel/seccomp.c:1954 __do_sys_prctl kernel/sys.c:2380 [inline] __se_sys_prctl+0x71f/0xfd0 kernel/sys.c:2298 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: 0033:0x7ff9b544e929 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:00007ff9b32b6038 EFLAGS: 00000246 ORIG_RAX: 000000000000009d RAX: ffffffffffffffda RBX: 00007ff9b5675fa0 RCX: 00007ff9b544e929 RDX: 0000200000000000 RSI: 0000000000000002 RDI: 0000000000000016 RBP: 00007ff9b54d0b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff9b5675fa0 R15: 00007ffe5e0b5398