====================================================== WARNING: possible circular locking dependency detected 5.15.180-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.27/4331 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: ffff88807837e1b8 (&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_8c8ab8634bca3061+0x3ed/0x5c4 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 __hrtimer_start_range_ns kernel/time/hrtimer.c:1249 [inline] hrtimer_start_range_ns+0xa7e/0xc20 kernel/time/hrtimer.c:1291 futex_wait_queue_me+0x18c/0x440 kernel/futex/core.c:2850 futex_wait+0x202/0x5c0 kernel/futex/core.c:2964 do_futex+0xd1c/0x1240 kernel/futex/core.c:3982 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040 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_8c8ab8634bca3061+0x3a/0x5c4 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 remove_vma mm/mmap.c:187 [inline] exit_mmap+0x4d8/0x5f0 mm/mmap.c:3215 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x599/0x20a0 kernel/exit.c:861 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 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 *** 2 locks held by syz.3.27/4331: #0: ffffffff8c11d9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 #1: ffff88807837e1b8 (&trie->lock){-...}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467 stack backtrace: CPU: 0 PID: 4331 Comm: syz.3.27 Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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_8c8ab8634bca3061+0x3a/0x5c4 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 remove_vma mm/mmap.c:187 [inline] exit_mmap+0x4d8/0x5f0 mm/mmap.c:3215 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x599/0x20a0 kernel/exit.c:861 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f29c5370969 Code: Unable to access opcode bytes at RIP 0x7f29c537093f. RSP: 002b:00007f29c31d80e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007f29c5597fa8 RCX: 00007f29c5370969 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f29c5597fac RBP: 00007f29c5597fa0 R08: 00221850e6f32aca R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 00007f29c5597fac R13: 0000000000000000 R14: 00007ffcc3c39a80 R15: 00007ffcc3c39b68