rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (10500 ticks this GP) idle=f514/1/0x4000000000000000 softirq=24201/24201 fqs=4125
rcu: hardirqs softirqs csw/system
rcu: number: 1437565 0 0
rcu: cputime: 17467 35002 59 ==> 52470(ms)
rcu: (t=10500 jiffies g=25989 q=708 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 576 jiffies! g25989 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=18599
rcu: rcu_preempt kthread starved for 583 jiffies! g25989 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:26856 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1088 Comm: kworker/u4:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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 18 af 51 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:ffffc9000438f3a0 EFLAGS: 00000206
RAX: 00000000000001ff RBX: 1ffff1100bc58105 RCX: ffffffff8a8daa62
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88805e2c0828
RBP: ffffc9000438f430 R08: ffff88805e2c082b R09: 1ffff1100bc58105
R10: dffffc0000000000 R11: ffffed100bc58106 R12: dffffc0000000000
R13: 1ffff92000871e74 R14: ffff88805e2c0828 R15: ffffc9000438f3d0
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0d5dc0700 CR3: 000000000cf32000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
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:543 [inline]
ip6_finish_output2+0xe2e/0x1620 net/ipv6/ip6_output.c:141
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:2653 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
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: 1 PID: 8358 Comm: syz.2.840 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:kasan_quarantine_put+0x88/0x220 mm/kasan/quarantine.c:243
Code: e8 1d ef ad ff 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 0f 85 83 00 00 00 41 f7 c7 00 02 00 00 74 01 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 40 7b 03 00 45
RSP: 0018:ffffc900001f0940 EFLAGS: 00000206
RAX: 61c82c64728eb301 RBX: ffff88804ca84800 RCX: 61c82c64728eb300
RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: ffffffff8b1c7be0
RBP: ffff88804ca84800 R08: ffffffff911bc5c7 R09: 1ffffffff22378b8
R10: dffffc0000000000 R11: fffffbfff22378b9 R12: 0000000000000000
R13: ffffc900001f09d8 R14: 000000000009d220 R15: 0000000000000286
FS: 00007f22b6e9a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 0000000077c84000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
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+0xba/0x1f0 mm/slub.c:3843
skb_kfree_head net/core/skbuff.c:946 [inline]
skb_free_head net/core/skbuff.c:958 [inline]
skb_release_data+0x609/0x7f0 net/core/skbuff.c:988
skb_release_all net/core/skbuff.c:1054 [inline]
__kfree_skb net/core/skbuff.c:1068 [inline]
kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1104
__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:generic_exec_single+0x477/0x4e0 kernel/smp.c:418
Code: 75 11 e8 2c 00 0b 00 48 85 db 75 16 e8 22 00 0b 00 eb 15 e8 1b 00 0b 00 e8 06 f3 07 09 48 85 db 74 ea e8 0c 00 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 04 2c 00 00 00 00 43 c7 44 2c 08
RSP: 0018:ffffc90003887a00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000080000
RDX: ffffc9000d79b000 RSI: 00000000000036d3 RDI: 00000000000036d4
RBP: ffffc90003887ad0 R08: ffffffff911bc5ff R09: 1ffffffff22378bf
R10: dffffc0000000000 R11: fffffbfff22378c0 R12: 1ffff92000710f44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92000710f65
smp_call_function_single+0x36d/0x5a0 kernel/smp.c:647
task_function_call kernel/events/core.c:120 [inline]
perf_install_in_context+0x5bb/0x920 kernel/events/core.c:2951
__do_sys_perf_event_open kernel/events/core.c:12949 [inline]
__se_sys_perf_event_open+0x1841/0x1c60 kernel/events/core.c:12601
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: 0033:0x7f22b5f9ce59
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:00007f22b6e9a028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f22b6215fa0 RCX: 00007f22b5f9ce59
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480
RBP: 00007f22b6032e6f R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22b6216038 R14: 00007f22b6215fa0 R15: 00007ffd3098cda8