====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.1031/9035 is trying to acquire lock: ffff8880b8f29370 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2959 [inline] ffff8880b8f29370 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3368 [inline] ffff8880b8f29370 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x166/0x790 kernel/rcu/tree.c:3453 but task is already holding lock: ffff8880b8f2b718 (hrtimer_bases.lock){-.-.}-{2:2}, at: lock_hrtimer_base kernel/time/hrtimer.c:181 [inline] ffff8880b8f2b718 (hrtimer_bases.lock){-.-.}-{2:2}, at: hrtimer_start_range_ns+0xf3/0xff0 kernel/time/hrtimer.c:1349 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (hrtimer_bases.lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 lock_hrtimer_base kernel/time/hrtimer.c:181 [inline] hrtimer_start_range_ns+0xf3/0xff0 kernel/time/hrtimer.c:1349 hrtimer_start include/linux/hrtimer.h:421 [inline] run_page_cache_worker kernel/rcu/tree.c:3350 [inline] kvfree_call_rcu+0x5e1/0x790 kernel/rcu/tree.c:3455 rtnl_register_internal+0x486/0x590 net/core/rtnetlink.c:264 rtnl_register+0x32/0x70 net/core/rtnetlink.c:314 ip_rt_init+0x2ec/0x390 net/ipv4/route.c:3801 ip_init+0xe/0x20 net/ipv4/ip_output.c:1668 inet_init+0x2c1/0x3e0 net/ipv4/af_inet.c:2024 do_one_initcall+0x242/0x790 init/main.c:1250 do_initcall_level+0x137/0x1f0 init/main.c:1312 do_initcalls+0x69/0xd0 init/main.c:1328 kernel_init_freeable+0x3ed/0x580 init/main.c:1565 kernel_init+0x1d/0x1c0 init/main.c:1455 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 -> #0 (krc.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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2959 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3368 [inline] kvfree_call_rcu+0x166/0x790 kernel/rcu/tree.c:3453 trie_delete_elem+0x534/0x6a0 kernel/bpf/lpm_trie.c:545 bpf_prog_5186c38a4019a4cb+0x4a/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:605 [inline] bpf_prog_run include/linux/filter.h:623 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x316/0x3e0 kernel/trace/bpf_trace.c:2361 __bpf_trace_hrtimer_start+0x123/0x170 include/trace/events/timer.h:202 __traceiter_hrtimer_start+0x6e/0xc0 include/trace/events/timer.h:202 trace_hrtimer_start include/trace/events/timer.h:202 [inline] debug_activate kernel/time/hrtimer.c:506 [inline] enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1108 __hrtimer_start_range_ns kernel/time/hrtimer.c:1290 [inline] hrtimer_start_range_ns+0xb4c/0xff0 kernel/time/hrtimer.c:1351 futex_wait_queue+0xac/0x1b0 kernel/futex/waitwake.c:342 futex_wait+0x1ec/0x5e0 kernel/futex/waitwake.c:656 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hrtimer_bases.lock); lock(krc.lock); lock(hrtimer_bases.lock); lock(krc.lock); *** DEADLOCK *** 2 locks held by syz.4.1031/9035: #0: ffff8880b8f2b718 (hrtimer_bases.lock){-.-.}-{2:2}, at: lock_hrtimer_base kernel/time/hrtimer.c:181 [inline] #0: ffff8880b8f2b718 (hrtimer_bases.lock){-.-.}-{2:2}, at: hrtimer_start_range_ns+0xf3/0xff0 kernel/time/hrtimer.c:1349 #1: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #1: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #1: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #1: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xe6/0x3e0 kernel/trace/bpf_trace.c:2361 stack backtrace: CPU: 1 PID: 9035 Comm: syz.4.1031 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2959 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3368 [inline] kvfree_call_rcu+0x166/0x790 kernel/rcu/tree.c:3453 trie_delete_elem+0x534/0x6a0 kernel/bpf/lpm_trie.c:545 bpf_prog_5186c38a4019a4cb+0x4a/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:605 [inline] bpf_prog_run include/linux/filter.h:623 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x316/0x3e0 kernel/trace/bpf_trace.c:2361 __bpf_trace_hrtimer_start+0x123/0x170 include/trace/events/timer.h:202 __traceiter_hrtimer_start+0x6e/0xc0 include/trace/events/timer.h:202 trace_hrtimer_start include/trace/events/timer.h:202 [inline] debug_activate kernel/time/hrtimer.c:506 [inline] enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1108 __hrtimer_start_range_ns kernel/time/hrtimer.c:1290 [inline] hrtimer_start_range_ns+0xb4c/0xff0 kernel/time/hrtimer.c:1351 futex_wait_queue+0xac/0x1b0 kernel/futex/waitwake.c:342 futex_wait+0x1ec/0x5e0 kernel/futex/waitwake.c:656 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f00d599acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffddb72e3c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 0000000000091ffb RCX: 00007f00d599acb9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f00d5c15fac RBP: 0000000000000032 R08: 0000000000745d1e R09: 0000000000000000 R10: 00007ffddb72e4d0 R11: 0000000000000246 R12: 00007ffddb72e4f0 R13: 00007f00d5c15fac R14: 000000000009202d R15: 00007ffddb72e4d0