syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8627/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=46353, q=2196 ncpus=2)
task:syz.6.664       state:R  running task     stack:25448 pid:8627  tgid:8625  ppid:6808   task_flags:0x40044c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893
Code: 90 97 11 00 00 00 00 eb b5 e8 45 e0 06 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 35 4b 97 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 05 5c 6e ff cc 48 8d 3d 32 33 92
RSP: 0018:ffffc90006d3f520 EFLAGS: 00000282
RAX: a9301793b6f68b00 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e219b5c RDI: ffffffff8c28af60
RBP: ffff88801f7c2a50 R08: ffffc90006d3fe90 R09: ffffc90006d3f678
R10: dffffc0000000000 R11: fffff52000da7ed1 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8e95cd60 R15: ffff88801f7c1ec0
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
 vfree+0x1d1/0x2f0 mm/vmalloc.c:3472
 kcov_put kernel/kcov.c:442 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:543
 __fput+0x44f/0xa60 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x70f/0x22c0 kernel/exit.c:975
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
 get_signal+0x1284/0x1330 kernel/signal.c:3037
 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efdc199ce59
RSP: 002b:00007efdc27990e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007efdc1c15fa8 RCX: 00007efdc199ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efdc1c15fa8
RBP: 00007efdc1c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efdc1c16038 R14: 00007ffe6b75f880 R15: 00007ffe6b75f968
 </TASK>
rcu: rcu_preempt kthread starved for 243 jiffies! g46353 f0x0 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:26880 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 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+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 29 Comm: kworker/1:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: wg-crypt-wg1 wg_packet_tx_worker
RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:748
Code: c7 c7 60 24 96 8e e8 9f 49 44 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 41 57 41 56 53 65 ff 05 70 56 8e 11 e8 ab 06 fe 09 89
RSP: 0018:ffffc90000a078f8 EFLAGS: 00000202
RAX: ffffffff897ad377 RBX: ffff888163ea7dd0 RCX: 0000000000000100
RDX: ffff88801f2c5c40 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000a07f38 R08: ffffffff897ad341 R09: ffffffff8e95cd60
R10: dffffc0000000000 R11: fffff52000140fff R12: dffffc0000000000
R13: 1ffff1102c7d4fba R14: 0000000000000001 R15: 1ffffffff1c50cd0
FS:  0000000000000000(0000) GS:ffff88812538d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000001e1030 CR3: 0000000040132000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_read_lock include/linux/rcupdate.h:839 [inline]
 __skb_flow_dissect+0x421/0x6e80 net/core/flow_dissector.c:1120
 __xfrm_decode_session+0xf3/0xbb0 net/xfrm/xfrm_policy.c:3508
 xfrm_decode_session include/net/xfrm.h:1337 [inline]
 ip_route_me_harder+0x9c0/0xf90 net/ipv4/netfilter.c:67
 synproxy_send_tcp+0x34c/0x670 net/netfilter/nf_synproxy_core.c:432
 synproxy_send_client_synack+0x8c1/0xe30 net/netfilter/nf_synproxy_core.c:485
 nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60
 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+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285
 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
 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:6202 [inline]
 __netif_receive_skb net/core/dev.c:6315 [inline]
 process_backlog+0xaa3/0x1950 net/core/dev.c:6666
 __napi_poll+0xae/0x340 net/core/dev.c:7730
 napi_poll net/core/dev.c:7793 [inline]
 net_rx_action+0x627/0xf70 net/core/dev.c:7950
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 keep_key_fresh drivers/net/wireguard/send.c:138 [inline]
 wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline]
 wg_packet_tx_worker+0x6be/0x7c0 drivers/net/wireguard/send.c:276
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>