======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.8.670/7690 is trying to acquire lock:
ffff8880b8f295a8 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2959 [inline]
ffff8880b8f295a8 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3368 [inline]
ffff8880b8f295a8 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x15a/0x780 kernel/rcu/tree.c:3453
but task is already holding lock:
ffff8880b8f297d8 (&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+0xa8/0xf0 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:999
__mod_timer+0xf9/0xdb0 kernel/time/timer.c:1080
queue_delayed_work_on+0x12a/0x1e0 kernel/workqueue.c:1987
kvfree_call_rcu+0x541/0x780 kernel/rcu/tree.c:3481
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:3796
ip_init+0xe/0x20 net/ipv4/ip_output.c:1663
inet_init+0x2c1/0x3e0 net/ipv4/af_inet.c:2024
do_one_initcall+0x1fd/0x750 init/main.c:1238
do_initcall_level+0x137/0x1f0 init/main.c:1300
do_initcalls+0x69/0xd0 init/main.c:1316
kernel_init_freeable+0x3d2/0x570 init/main.c:1553
kernel_init+0x1d/0x1c0 init/main.c:1443
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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 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+0x15a/0x780 kernel/rcu/tree.c:3453
trie_delete_elem+0x535/0x6a0 kernel/bpf/lpm_trie.c:545
bpf_prog_18a85c48b7f32964+0x45/0x49
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run3+0x1e7/0x400 kernel/trace/bpf_trace.c:2362
__bpf_trace_timer_start+0x14a/0x1b0 include/trace/events/timer.h:53
trace_timer_start include/trace/events/timer.h:53 [inline]
enqueue_timer+0x398/0x530 kernel/time/timer.c:609
internal_add_timer kernel/time/timer.c:634 [inline]
__mod_timer+0x977/0xdb0 kernel/time/timer.c:1131
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1751 [inline]
__run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13
rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0xba/0x8b0 kernel/locking/lockdep.c:5765
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
futex_queue kernel/futex/futex.h:174 [inline]
futex_wait_queue+0x9d/0x1b0 kernel/futex/waitwake.c:338
futex_wait+0x19f/0x530 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:106
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 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 ***
4 locks held by syz.8.670/7690:
#0: ffffc90000a2daa0 (&futex_queues[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#0: ffffc90000a2daa0 (&futex_queues[i].lock){+.+.}-{2:2}, at: futex_q_lock+0x1aa/0x250 kernel/futex/core.c:542
#1: ffffc900001f0c00 ((&app->join_timer)#2){+.-.}-{0:0}, at: call_timer_fn+0xbf/0x530 kernel/time/timer.c:1697
#2: ffff8880b8f297d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
#3: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#3: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#3: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline]
#3: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf4/0x400 kernel/trace/bpf_trace.c:2362
stack backtrace:
CPU: 1 PID: 7690 Comm: syz.8.670 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
check_noncircular+0x2bd/0x3c0 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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 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+0x15a/0x780 kernel/rcu/tree.c:3453
trie_delete_elem+0x535/0x6a0 kernel/bpf/lpm_trie.c:545
bpf_prog_18a85c48b7f32964+0x45/0x49
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run3+0x1e7/0x400 kernel/trace/bpf_trace.c:2362
__bpf_trace_timer_start+0x14a/0x1b0 include/trace/events/timer.h:53
trace_timer_start include/trace/events/timer.h:53 [inline]
enqueue_timer+0x398/0x530 kernel/time/timer.c:609
internal_add_timer kernel/time/timer.c:634 [inline]
__mod_timer+0x977/0xdb0 kernel/time/timer.c:1131
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1751 [inline]
__run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13
Code: e9 6e ff ff ff cc cc cc cc f3 0f 1e fa 48 c7 c7 60 70 fc 8a 48 c7 c6 a0 70 fc 8a eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24
RSP: 0018:ffffc900030a79b0 EFLAGS: 00000283
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816782bb
RDX: 0000000000000000 RSI: ffffffff8afc70a0 RDI: ffffffff8afc7060
RBP: ffffc900030a7af8 R08: ffffffff8e4a912f R09: 1ffffffff1c95225
R10: dffffc0000000000 R11: fffffbfff1c95226 R12: ffffffff817a66ad
R13: dffffc0000000000 R14: ffffffff817a6637 R15: 1ffff92000614f48
rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0xba/0x8b0 kernel/locking/lockdep.c:5765
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
futex_queue kernel/futex/futex.h:174 [inline]
futex_wait_queue+0x9d/0x1b0 kernel/futex/waitwake.c:338
futex_wait+0x19f/0x530 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:106
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f303958ebe9
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:00007ffe7dbebe08 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000003b979 RCX: 00007f303958ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f30397c5fac
RBP: 0000000000000226 R08: 0000000000745aed R09: 0000000e7dbec0ff
R10: 00007ffe7dbebf00 R11: 0000000000000246 R12: 00007f30397c5fac
R13: 00007ffe7dbebf00 R14: 000000000003bb9f R15: 00007ffe7dbebf20
----------------
Code disassembly (best guess):
0: e9 6e ff ff ff jmp 0xffffff73
5: cc int3
6: cc int3
7: cc int3
8: cc int3
9: f3 0f 1e fa endbr64
d: 48 c7 c7 60 70 fc 8a mov $0xffffffff8afc7060,%rdi
14: 48 c7 c6 a0 70 fc 8a mov $0xffffffff8afc70a0,%rsi
1b: eb 0c jmp 0x29
1d: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1)
24: 00 00 00
27: 66 90 xchg %ax,%ax
29: 55 push %rbp
* 2a: 41 57 push %r15 <-- trapping instruction
2c: 41 56 push %r14
2e: 53 push %rbx
2f: 48 83 ec 10 sub $0x10,%rsp
33: 65 48 8b 04 25 28 00 mov %gs:0x28,%rax
3a: 00 00
3c: 48 rex.W
3d: 89 .byte 0x89
3e: 44 rex.R
3f: 24 .byte 0x24