======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.146/4921 is trying to acquire lock:
ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
ffff8880b8e281d8 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3406
but task is already holding lock:
ffff8880b8e28418 (&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+0xa4/0xf0 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:999
__mod_timer+0x117/0xd20 kernel/time/timer.c:1072
queue_delayed_work_on+0x126/0x1e0 kernel/workqueue.c:1704
queue_delayed_work include/linux/workqueue.h:527 [inline]
schedule_delayed_monitor_work kernel/rcu/tree.c:3176 [inline]
kvfree_call_rcu+0x4cb/0x870 kernel/rcu/tree.c:3432
rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:260
rtnl_register+0x2e/0x70 net/core/rtnetlink.c:310
ip_rt_init+0x323/0x3b5 net/ipv4/route.c:3796
ip_init+0xa/0x14 net/ipv4/ip_output.c:1771
inet_init+0x2bd/0x3cf net/ipv4/af_inet.c:2033
do_one_initcall+0x214/0x7a0 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x3fa/0x5ac init/main.c:1638
kernel_init+0x19/0x1b0 init/main.c:1526
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
-> #0 (krc.lock){..-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3406
trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545
bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
bpf_trace_run3+0x1e3/0x400 kernel/trace/bpf_trace.c:2325
trace_timer_start include/trace/events/timer.h:53 [inline]
enqueue_timer+0x411/0x5c0 kernel/time/timer.c:609
internal_add_timer kernel/time/timer.c:634 [inline]
__mod_timer+0x8e1/0xd20 kernel/time/timer.c:1115
mrp_join_timer_arm net/802/mrp.c:596 [inline]
mrp_join_timer+0x13b/0x170 net/802/mrp.c:611
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
try_to_wake_up+0x64c/0x1080 kernel/sched/core.c:4229
wake_up_process kernel/sched/core.c:4361 [inline]
wake_up_q+0x78/0xc0 kernel/sched/core.c:1009
futex_wake+0x409/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x2e2/0x320 kernel/futex/syscalls.c:111
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x14a/0x440 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 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.3.146/4921:
#0: ffffc90000007bc0 ((&app->join_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc1/0x670 kernel/time/timer.c:1501
#1: ffff888057e6ecc8 (&app->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#1: ffff888057e6ecc8 (&app->lock){+.-.}-{2:2}, at: mrp_join_timer+0xd4/0x170 net/802/mrp.c:609
#2: ffff8880b8e28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
#3: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#3: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#3: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
#3: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf0/0x400 kernel/trace/bpf_trace.c:2325
stack backtrace:
CPU: 0 PID: 4921 Comm: syz.3.146 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3406
trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545
bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
bpf_trace_run3+0x1e3/0x400 kernel/trace/bpf_trace.c:2325
trace_timer_start include/trace/events/timer.h:53 [inline]
enqueue_timer+0x411/0x5c0 kernel/time/timer.c:609
internal_add_timer kernel/time/timer.c:634 [inline]
__mod_timer+0x8e1/0xd20 kernel/time/timer.c:1115
mrp_join_timer_arm net/802/mrp.c:596 [inline]
mrp_join_timer+0x13b/0x170 net/802/mrp.c:611
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 4e 55 65 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 c6 dd 35 f7 65 8b 05 47 95 e0 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90004067ac0 EFLAGS: 00000206
RAX: b5ad77c683e4b700 RBX: 0000000000000a02 RCX: b5ad77c683e4b700
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: 0000000000000001
RBP: ffffc90004067b48 R08: dffffc0000000000 R09: ffffed1004a7a141
R10: ffffed1004a7a141 R11: 1ffff11004a7a140 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff8880253d0a00 R15: 1ffff9200080cf58
try_to_wake_up+0x64c/0x1080 kernel/sched/core.c:4229
wake_up_process kernel/sched/core.c:4361 [inline]
wake_up_q+0x78/0xc0 kernel/sched/core.c:1009
futex_wake+0x409/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x2e2/0x320 kernel/futex/syscalls.c:111
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x14a/0x440 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0a4b58efc9
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:00007f0a4c43d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f0a4b7e5fa8 RCX: 00007f0a4b58efc9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f0a4b7e5fac
RBP: 00007f0a4b7e5fa0 R08: 0029710e003f1738 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0a4b7e6038 R14: 00007ffcde03e740 R15: 00007ffcde03e828
----------------
Code disassembly (best guess):
0: 74 05 je 0x7
2: e8 4e 55 65 f7 call 0xf7655555
7: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp)
e: 00 00
10: 9c pushf
11: 8f 44 24 20 pop 0x20(%rsp)
15: f6 44 24 21 02 testb $0x2,0x21(%rsp)
1a: 75 4b jne 0x67
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 c6 dd 35 f7 call 0xf735ddf5 <-- trapping instruction
2f: 65 8b 05 47 95 e0 75 mov %gs:0x75e09547(%rip),%eax # 0x75e0957d
36: 85 c0 test %eax,%eax
38: 74 3c je 0x76
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss