======================================================
WARNING: possible circular locking dependency detected
6.1.147-syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:15/6854 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:3793
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:1298
do_initcall_level+0x137/0x1e4 init/main.c:1371
do_initcalls+0x4b/0x8a init/main.c:1387
kernel_init_freeable+0x3fa/0x5ac init/main.c:1626
kernel_init+0x19/0x1b0 init/main.c:1514
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_1db1603a7cfa36fb+0x3d/0x41
bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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
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
lockdep_unregister_key+0x4c3/0x530 kernel/locking/lockdep.c:6370
wq_unregister_lockdep kernel/workqueue.c:3500 [inline]
pwq_unbound_release_workfn+0x262/0x2b0 kernel/workqueue.c:3738
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
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 ***
5 locks held by kworker/0:15/6854:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90003587d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffc90000007bc0 ((&app->join_timer)#2){+.-.}-{0:0}, at: call_timer_fn+0xc1/0x670 kernel/time/timer.c:1501
#3: ffff8880b8e28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
#4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
#4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf0/0x400 kernel/trace/bpf_trace.c:2325
stack backtrace:
CPU: 0 PID: 6854 Comm: kworker/0:15 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events pwq_unbound_release_workfn
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_1db1603a7cfa36fb+0x3d/0x41
bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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
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:lockdep_unregister_key+0x4c3/0x530 kernel/locking/lockdep.c:6370
Code: d1 a8 90 48 c7 c6 10 91 63 81 e8 88 93 07 00 e8 e3 a6 07 00 e9 86 fc ff ff e8 69 91 b2 08 41 f7 c4 00 02 00 00 74 d1 fb 84 db <75> d0 eb e1 0f 0b eb a1 0f 0b e9 11 ff ff ff 0f 0b e9 5e ff ff ff
RSP: 0018:ffffc90003587b20 EFLAGS: 00000246
RAX: 3c8ba39a55fe7600 RBX: 0000000000000000 RCX: 3c8ba39a55fe7600
RDX: 0000000000000001 RSI: ffffffff8a8c1140 RDI: ffffffff8adef320
RBP: ffffc90003587bf0 R08: dffffc0000000000 R09: fffffbfff2155e14
R10: fffffbfff2155e14 R11: 1ffffffff2155e13 R12: 0000000000000206
R13: ffff88807d272129 R14: ffffffff90aad1a8 R15: 1ffff920006b0f68
wq_unregister_lockdep kernel/workqueue.c:3500 [inline]
pwq_unbound_release_workfn+0x262/0x2b0 kernel/workqueue.c:3738
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
----------------
Code disassembly (best guess), 1 bytes skipped:
0: a8 90 test $0x90,%al
2: 48 c7 c6 10 91 63 81 mov $0xffffffff81639110,%rsi
9: e8 88 93 07 00 call 0x79396
e: e8 e3 a6 07 00 call 0x7a6f6
13: e9 86 fc ff ff jmp 0xfffffc9e
18: e8 69 91 b2 08 call 0x8b29186
1d: 41 f7 c4 00 02 00 00 test $0x200,%r12d
24: 74 d1 je 0xfffffff7
26: fb sti
27: 84 db test %bl,%bl
* 29: 75 d0 jne 0xfffffffb <-- trapping instruction
2b: eb e1 jmp 0xe
2d: 0f 0b ud2
2f: eb a1 jmp 0xffffffd2
31: 0f 0b ud2
33: e9 11 ff ff ff jmp 0xffffff49
38: 0f 0b ud2
3a: e9 5e ff ff ff jmp 0xffffff9d