rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (10500 ticks this GP) idle=2b6c/1/0x4000000000000000 softirq=128303/128303 fqs=4124
rcu: hardirqs softirqs csw/system
rcu: number: 1250767 0 0
rcu: cputime: 18607 33871 61 ==> 52480(ms)
rcu: (t=10500 jiffies g=146901 q=1738 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 425 jiffies! g146901 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=74377
rcu: rcu_preempt kthread starved for 432 jiffies! g146901 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack:27080 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6701
schedule+0xbd/0x170 kernel/sched/core.c:6775
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 24143 Comm: kworker/u4:74 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:queued_write_lock_slowpath+0x12c/0x29f kernel/locking/qrwlock.c:85
Code: f0 41 81 0e 00 01 00 00 42 0f b6 04 23 84 c0 74 37 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 2a 4c 89 f7 e8 78 87 43 f7 eb 20 f3 90 <42> 0f b6 04 23 84 c0 74 15 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 08
RSP: 0018:ffffc9000c8973a0 EFLAGS: 00000206
RAX: 00000000000001ff RBX: 1ffff1100ed05805 RCX: ffffffff8a9cea22
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88807682c028
RBP: ffffc9000c897430 R08: ffff88807682c02b R09: 1ffff1100ed05805
R10: dffffc0000000000 R11: ffffed100ed05806 R12: dffffc0000000000
R13: 1ffff92001912e74 R14: ffff88807682c028 R15: ffffc9000c8973d0
FS: 0000000000000000(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbaa7e4021b CR3: 000000000dd32000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000008d24
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
queued_write_lock include/asm-generic/qrwlock.h:101 [inline]
do_raw_write_lock+0x1ea/0x260 kernel/locking/spinlock_debug.c:210
__neigh_event_send+0x39/0x1480 net/core/neighbour.c:1182
neigh_event_send_probe include/net/neighbour.h:467 [inline]
neigh_event_send include/net/neighbour.h:473 [inline]
neigh_resolve_output+0x1a4/0x710 net/core/neighbour.c:1552
neigh_output include/net/neighbour.h:547 [inline]
ip6_finish_output2+0xf7a/0x1690 net/ipv6/ip6_output.c:143
ip6tunnel_xmit include/net/ip6_tunnel.h:161 [inline]
udp_tunnel6_xmit_skb+0x516/0x930 net/ipv6/ip6_udp_tunnel.c:110
send6+0x608/0x950 drivers/net/wireguard/socket.c:152
wg_socket_send_skb_to_peer+0x111/0x1c0 drivers/net/wireguard/socket.c:178
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x207/0x360 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:2657 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
CPU: 0 PID: 27525 Comm: syz.4.5410 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:__unwind_start+0x27f/0x730 arch/x86/kernel/unwind_orc.c:714
Code: c6 04 24 01 c7 04 24 00 00 00 00 e9 59 01 00 00 e8 f6 ab 4b 00 48 8d 6b 48 4c 8d 2d 00 00 00 00 49 89 e4 48 89 e8 48 89 04 24 <48> 89 e8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 ef e8 9b 8d a4 00
RSP: 0018:ffffc90000007608 EFLAGS: 00000246
RAX: ffffc900000076b0 RBX: ffffc90000007668 RCX: ffff8880639ebc00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffc900000076c8
RBP: ffffc900000076b0 R08: ffffc900000076c7 R09: 0000000000000000
R10: ffffc90000007668 R11: fffff52000000ed9 R12: ffffc90000007608
R13: ffffffff813be4c5 R14: 1ffff92000000ed2 R15: dffffc0000000000
FS: 00007f3646c886c0(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3645debc40 CR3: 00000000661ab000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x290 mm/slub.c:3852
__skb_queue_purge_reason include/linux/skbuff.h:3245 [inline]
__skb_queue_purge include/linux/skbuff.h:3250 [inline]
neigh_invalidate+0x39e/0x460 net/core/neighbour.c:1067
neigh_timer_handler+0x911/0xff0 net/core/neighbour.c:1151
call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x570/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x27d/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 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:raw_spin_rq_unlock_irq+0x13/0x90 kernel/sched/sched.h:1392
Code: 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 73 bd 33 09 0f 1f 00 41 57 41 56 53 66 90 e8 34 77 3d 09 e8 7f b5 2e 00 fb 5b <41> 5e 41 5f c3 49 be 00 00 00 00 00 fc ff df 49 89 ff 48 8d 9f 58
RSP: 0018:ffffc9000ecaf7a8 EFLAGS: 00000286
RAX: fe1478b717c81b00 RBX: ffff8880639ebc00 RCX: fe1478b717c81b00
RDX: dffffc0000000000 RSI: ffffffff8acacfe0 RDI: ffffffff8b1d5160
RBP: ffffc9000ecaf9d0 R08: ffffffff91ff1607 R09: 1ffffffff23fe2c0
R10: dffffc0000000000 R11: fffffbfff23fe2c1 R12: ffff8880639ebe90
R13: dffffc0000000000 R14: ffff8880639ebc00 R15: ffff8880b8c3c240
__schedule+0x1805/0x4660 kernel/sched/core.c:6705
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
smp_call_function_single+0x48d/0x5a0 kernel/smp.c:652
task_function_call kernel/events/core.c:120 [inline]
perf_install_in_context+0x5bb/0x920 kernel/events/core.c:2958
__do_sys_perf_event_open kernel/events/core.c:12967 [inline]
__se_sys_perf_event_open+0x1818/0x1d40 kernel/events/core.c:12609
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3645d9e559
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:00007f3646c88028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f3646026180 RCX: 00007f3645d9e559
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000140
RBP: 00007f3645e35ab8 R08: 0000000000000002 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3646026218 R14: 00007f3646026180 R15: 00007fff405809b8