======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
swapper/1/0 is trying to acquire lock:
ffff88801f902a38 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
but task is already holding lock:
ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:946
__mod_timer+0xfe/0xd00 kernel/time/timer.c:1027
queue_delayed_work_on+0x12d/0x1f0 kernel/workqueue.c:1715
queue_delayed_work include/linux/workqueue.h:527 [inline]
schedule_delayed_work include/linux/workqueue.h:631 [inline]
kvfree_call_rcu+0x4bc/0x7d0 kernel/rcu/tree.c:3629
rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:225
rtnl_register+0x2e/0x70 net/core/rtnetlink.c:275
ip_rt_init+0x2e0/0x3a0 net/ipv4/route.c:3803
ip_init+0xa/0x20 net/ipv4/ip_output.c:1756
inet_init+0x28b/0x3a0 net/ipv4/af_inet.c:2007
do_one_initcall+0x272/0x730 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3e9/0x570 init/main.c:1629
kernel_init+0x19/0x1b0 init/main.c:1520
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
-> #1 (krc.lock){..-.}-{2:2}:
__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:3203 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3510 [inline]
kvfree_call_rcu+0x18d/0x7d0 kernel/rcu/tree.c:3601
trie_update_elem+0x86c/0xc50 kernel/bpf/lpm_trie.c:396
bpf_map_update_value+0x57d/0x650 kernel/bpf/syscall.c:223
generic_map_update_batch+0x52d/0x7d0 kernel/bpf/syscall.c:1430
bpf_map_do_batch+0x466/0x600 kernel/bpf/syscall.c:-1
__sys_bpf+0x671/0x6f0 kernel/bpf/syscall.c:-1
__do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
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
-> #0 (&trie->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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
bpf_prog_5186c38a4019a4cb+0x42/0x1a4
bpf_dispatcher_nop_func include/linux/bpf.h:888 [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+0x19e/0x350 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
internal_add_timer kernel/time/timer.c:611 [inline]
__mod_timer+0x911/0xd00 kernel/time/timer.c:1078
queue_delayed_work_on+0x12d/0x1f0 kernel/workqueue.c:1715
queue_delayed_work include/linux/workqueue.h:527 [inline]
srcu_funnel_gp_start kernel/rcu/srcutree.c:682 [inline]
srcu_gp_start_if_needed+0x60d/0x960 kernel/rcu/srcutree.c:838
rcu_do_batch kernel/rcu/tree.c:2523 [inline]
rcu_core+0x9d2/0x1670 kernel/rcu/tree.c:2763
handle_softirqs+0x339/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11f7/0x43c0 kernel/sched/core.c:6395
schedule_idle+0x4a/0x90 kernel/sched/core.c:6506
do_idle+0x606/0x650 kernel/sched/idle.c:355
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424
start_secondary+0x330/0x430 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xb1/0xbb
other info that might help us debug this:
Chain exists of:
&trie->lock --> krc.lock --> &base->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&base->lock);
lock(krc.lock);
lock(&base->lock);
lock(&trie->lock);
*** DEADLOCK ***
5 locks held by swapper/1/0:
#0: ffffffff8c31ec40 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x0/0x20
#1: ffffffff8c35e718 (tracepoint_srcu){....}-{0:0}, at: rcu_lock_acquire+0x0/0x20
#2: ffffffff8c35e490 (tracepoint_srcu.lock){..-.}-{2:2}, at: srcu_funnel_gp_start kernel/rcu/srcutree.c:665 [inline]
#2: ffffffff8c35e490 (tracepoint_srcu.lock){..-.}-{2:2}, at: srcu_gp_start_if_needed+0x481/0x960 kernel/rcu/srcutree.c:838
#3: ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
#4: ffffffff8c31eb20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_noncircular+0x296/0x330 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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
bpf_prog_5186c38a4019a4cb+0x42/0x1a4
bpf_dispatcher_nop_func include/linux/bpf.h:888 [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+0x19e/0x350 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
internal_add_timer kernel/time/timer.c:611 [inline]
__mod_timer+0x911/0xd00 kernel/time/timer.c:1078
queue_delayed_work_on+0x12d/0x1f0 kernel/workqueue.c:1715
queue_delayed_work include/linux/workqueue.h:527 [inline]
srcu_funnel_gp_start kernel/rcu/srcutree.c:682 [inline]
srcu_gp_start_if_needed+0x60d/0x960 kernel/rcu/srcutree.c:838
rcu_do_batch kernel/rcu/tree.c:2523 [inline]
rcu_core+0x9d2/0x1670 kernel/rcu/tree.c:2763
handle_softirqs+0x339/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 3c 52 68 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 e6 bd 71 08 e8 61 e6 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 c9 09 fe ff 43 80 3c
RSP: 0018:ffffc90000d67ac8 EFLAGS: 00000282
RAX: 94039320d7cd2100 RBX: ffff8880b913a340 RCX: 94039320d7cd2100
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: ffffffff8a79fe00
RBP: 1ffff11017227613 R08: ffff8880b913a343 R09: 1ffff11017227468
R10: dffffc0000000000 R11: ffffed1017227469 R12: 1ffff110172275c1
R13: dffffc0000000000 R14: ffff8880b913ae08 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11f7/0x43c0 kernel/sched/core.c:6395
schedule_idle+0x4a/0x90 kernel/sched/core.c:6506
do_idle+0x606/0x650 kernel/sched/idle.c:355
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424
start_secondary+0x330/0x430 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xb1/0xbb
----------------
Code disassembly (best guess):
0: be ff ff ff ff mov $0xffffffff,%esi
5: e8 3c 52 68 08 call 0x8685246
a: 85 c0 test %eax,%eax
c: 74 4a je 0x58
e: 4d 85 ff test %r15,%r15
11: 75 66 jne 0x79
13: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
18: 48 89 df mov %rbx,%rdi
1b: e8 e6 bd 71 08 call 0x871be06
20: e8 61 e6 2a 00 call 0x2ae686
25: fb sti
26: 48 83 c4 08 add $0x8,%rsp
* 2a: 5b pop %rbx <-- trapping instruction
2b: 41 5c pop %r12
2d: 41 5d pop %r13
2f: 41 5e pop %r14
31: 41 5f pop %r15
33: 5d pop %rbp
34: c3 ret
35: 48 89 df mov %rbx,%rdi
38: e8 c9 09 fe ff call 0xfffe0a06
3d: 43 rex.XB
3e: 80 .byte 0x80
3f: 3c .byte 0x3c