rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8695/3:b..l
rcu: (detected by 0, t=10503 jiffies, g=169293, q=946752 ncpus=2)
task:syz.6.10541 state:R running task stack:24024 pid:8695 tgid:8694 ppid:6243 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6908
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7092
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline]
__dev_queue_xmit+0x1e78/0x3890 net/core/dev.c:4873
dev_queue_xmit include/linux/netdevice.h:3385 [inline]
neigh_hh_output include/net/neighbour.h:540 [inline]
neigh_output include/net/neighbour.h:554 [inline]
ip_finish_output2+0xc68/0x1070 net/ipv4/ip_output.c:237
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
__ip_queue_xmit+0x116a/0x1bb0 net/ipv4/ip_output.c:534
__tcp_transmit_skb+0x2b30/0x43e0 net/ipv4/tcp_output.c:1693
tcp_transmit_skb net/ipv4/tcp_output.c:1711 [inline]
tcp_send_syn_data net/ipv4/tcp_output.c:4287 [inline]
tcp_connect+0x3361/0x5370 net/ipv4/tcp_output.c:4376
tcp_v4_connect+0x10f6/0x19b0 net/ipv4/tcp_ipv4.c:346
__inet_stream_connect+0x25a/0xdd0 net/ipv4/af_inet.c:685
tcp_sendmsg_fastopen+0x3a7/0x5e0 net/ipv4/tcp.c:1099
tcp_sendmsg_locked+0x4bb2/0x5490 net/ipv4/tcp.c:1195
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1465
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
__sys_sendto+0x5de/0x710 net/socket.c:2206
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2209
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1b1679c799
RSP: 002b:00007f1b175b6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f1b16a15fa0 RCX: 00007f1b1679c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f1b16832c99 R08: 0000200000e68000 R09: 0000000000000010
R10: 00000000200007fd R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1b16a16038 R14: 00007f1b16a15fa0 R15: 00007ffcd2dfadc8
rcu: rcu_preempt kthread starved for 603 jiffies! g169293 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27656 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6908
__schedule_loop kernel/sched/core.c:6990 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7005
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 4534 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker
RIP: 0010:__lock_acquire+0x86b/0x2cf0 kernel/locking/lockdep.c:-1
Code: 06 31 da 01 c1 29 d0 89 d6 c1 c6 08 31 c6 01 ca 29 f1 89 f3 c1 c3 10 31 cb 01 d6 29 da 89 dd c1 c5 13 31 d5 01 f3 29 ee 01 eb c5 04 31 f5 48 c1 e5 20 83 3d 69 36 70 0e 00 4d 89 e5 0f 85 1f
RSP: 0018:ffffc90000a07d58 EFLAGS: 00000817
RAX: 00000000d7bb2776 RBX: 000000006290c103 RCX: 00000000071bee9f
RDX: 00000000a42637f2 RSI: 00000000db147cf1 RDI: ffff888035808000
RBP: 000000009e246e69 R08: ffffffff81767de5 R09: ffffffff8e75e420
R10: ffffc90000a08038 R11: ffffffff81b0bfa0 R12: ffff888035808c48
R13: ffff888035808c48 R14: ffff888035808000 R15: 0000000000000006
FS: 0000000000000000(0000) GS:ffff888125560000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000076066000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2692 [inline]
slab_free mm/slub.c:6168 [inline]
kmem_cache_free+0x187/0x630 mm/slub.c:6298
nft_synproxy_eval_v4+0x352/0x4e0 net/netfilter/nft_synproxy.c:61
nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x45e/0x1990 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x29d/0x380 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6164 [inline]
__netif_receive_skb net/core/dev.c:6277 [inline]
process_backlog+0xaa3/0x1950 net/core/dev.c:6628
__napi_poll+0xae/0x340 net/core/dev.c:7692
napi_poll net/core/dev.c:7755 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7912
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:mix_hash drivers/net/wireguard/noise.c:440 [inline]
RIP: 0010:message_encrypt drivers/net/wireguard/noise.c:470 [inline]
RIP: 0010:wg_noise_handshake_create_initiation+0x3fa/0x830 drivers/net/wireguard/noise.c:555
Code: e8 3b 8c 40 fe ba 30 00 00 00 4c 89 ef 4c 89 f6 e8 2b 8c 40 fe 4c 89 ef 4c 89 e6 e8 40 af 40 fe 48 b8 f8 f8 f8 f8 f8 f8 f8 f8 <48> 89 43 1c c7 43 24 f8 f8 f8 f8 66 c7 43 28 f8 f8 c6 43 2a f8 4d
RSP: 0018:ffffc9000e9cf6c0 EFLAGS: 00000286
RAX: f8f8f8f8f8f8f8f8 RBX: fffff52001d39ee0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000e9cf858
RBP: ffffc9000e9cf970 R08: ffffc9000e9cf857 R09: 0000000000000000
R10: ffffc9000e9cf7e0 R11: fffff52001d39f0b R12: ffff888055429648
R13: ffffc9000e9cf7e0 R14: ffffc9000e9cf9e8 R15: ffff888055429570
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline]
wg_packet_handshake_send_worker+0x18d/0x350 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245