rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18895/1:b..l rcu: (detected by 0, t=10502 jiffies, g=64313, q=889868 ncpus=2) task:syz.6.3606 state:R running task stack:25960 pid:18895 tgid:18895 ppid:16204 task_flags:0x400040 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x44/0x3e0 kernel/locking/lockdep.c:5879 Code: 8b 05 d0 ec d0 10 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 d3 ec d0 10 83 f8 08 0f 83 9a 02 00 00 89 c0 48 0f a3 05 fc 7e df 0d <73> 16 e8 d5 ec 08 00 84 c0 75 0d f6 05 88 8a c9 0d 01 0f 84 ad 02 RSP: 0018:ffffc9000cce70f0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff90175b01 RCX: 8181066b57e16600 RDX: ffffc9000cce7201 RSI: ffffffff81738d25 RDI: ffffffff8df3d660 RBP: dffffc0000000000 R08: ffffc9000cce75a0 R09: 0000000000000000 R10: ffffc9000cce7278 R11: fffff5200199ce51 R12: ffffc9000cce75b0 R13: ffffffff81738d25 R14: ffffffff8df3d660 R15: ffffffff81738d25 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:311 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906 discard_slab mm/slub.c:3326 [inline] __put_partials+0x146/0x170 mm/slub.c:3872 put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3947 __slab_free+0x2b9/0x390 mm/slub.c:5921 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4970 [inline] slab_alloc_node mm/slub.c:5280 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5287 vm_area_alloc+0x24/0x140 mm/vma_init.c:32 __mmap_new_vma mm/vma.c:2461 [inline] __mmap_region mm/vma.c:2670 [inline] mmap_region+0xdcd/0x2110 mm/vma.c:2740 do_mmap+0xc45/0x10d0 mm/mmap.c:558 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9f77f8f703 RSP: 002b:00007fff9cf02628 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f9f781e6308 RCX: 00007f9f77f8f703 RDX: 0000000000000000 RSI: 0000000000402000 RDI: 0000000000000000 RBP: 00007f9f781e6270 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000022 R11: 0000000000000246 R12: 00007f9f781e5fa0 R13: 00007f9f781e6270 R14: 0000000000000f58 R15: 0000000000000003 rcu: rcu_preempt kthread starved for 1798 jiffies! g64313 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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: 7372 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker RIP: 0010:unwind_next_frame+0x15d/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 5d 00 48 85 db 74 23 48 81 c3 88 00 00 00 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 45 1b 00 00 f6 03 03 0f 85 e4 17 00 00 <49> 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 44 24 28 0f b6 04 28 84 c0 RSP: 0018:ffffc90000a076b8 EFLAGS: 00000246 RAX: 1ffff92000140efb RBX: 0000000000000000 RCX: fb2b5228cf18e600 RDX: 0000000000000000 RSI: ffffffff8bbf0740 RDI: ffffffff8bbf0700 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff81738d25 R10: ffffc90000a077d8 R11: ffffffff81ac2f50 R12: 1ffff92000140ef1 R13: ffffc90000a077d8 R14: ffffc90000a07788 R15: ffffffff81738d25 FS: 0000000000000000(0000) GS:ffff88812623b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9f78db8f98 CR3: 0000000077936000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5763 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ref_tracker_alloc+0x133/0x460 lib/ref_tracker.c:271 __netdev_tracker_alloc include/linux/netdevice.h:4375 [inline] netdev_hold include/linux/netdevice.h:4404 [inline] dst_init+0xd9/0x450 net/core/dst.c:52 dst_alloc+0x12a/0x170 net/core/dst.c:93 rt_dst_alloc net/ipv4/route.c:1646 [inline] __mkroute_output net/ipv4/route.c:2650 [inline] ip_route_output_key_hash_rcu+0x1560/0x23e0 net/ipv4/route.c:2870 ip_route_output_key_hash+0x174/0x280 net/ipv4/route.c:2700 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2927 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x6c4/0xf10 net/ipv4/netfilter.c:53 synproxy_send_tcp+0x3a7/0x700 net/netfilter/nf_synproxy_core.c:431 synproxy_send_client_synack+0x8bb/0xe20 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x36e/0x560 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x25d/0x340 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+0x206/0x3a0 include/linux/netfilter.h:316 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6079 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6192 process_backlog+0x60e/0x14f0 net/core/dev.c:6544 __napi_poll+0xc7/0x360 net/core/dev.c:7594 napi_poll net/core/dev.c:7657 [inline] net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784 handle_softirqs+0x286/0x870 kernel/softirq.c:622 do_softirq+0xec/0x180 kernel/softirq.c:523 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline] kernel_fpu_end+0xd2/0x120 arch/x86/kernel/fpu/core.c:479 blake2s_compress+0xe9/0x1b80 lib/crypto/x86/blake2s.h:44 blake2s_update+0x14b/0x450 lib/crypto/blake2s.c:126 hmac+0x288/0x330 drivers/net/wireguard/noise.c:332 kdf drivers/net/wireguard/noise.c:367 [inline] message_ephemeral+0x1e2/0x280 drivers/net/wireguard/noise.c:493 wg_noise_handshake_create_initiation+0x229/0x750 drivers/net/wireguard/noise.c:545 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0x163/0x320 drivers/net/wireguard/send.c:51 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245