rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=2a84/1/0x4000000000000000 softirq=27507/27509 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=14497, q=346 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted 6.15.0-rc6-syzkaller-g088d13246a46 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:411 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 e9 ab c6 bb f5 cc RSP: 0018:ffffc90000a08d88 EFLAGS: 00000046 RAX: 0000000080010201 RBX: ffff88807a585340 RCX: ffffffff8981b876 RDX: ffff88801dac0000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880b8527840 R13: 0000000000000000 R14: ffff88807a585340 R15: ffffffff8981b030 FS: 0000000000000000(0000) GS:ffff888124adf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f37ade46f98 CR3: 00000000753ac000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: advance_sched+0x846/0xc80 net/sched/sch_taprio.c:925 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:blake2s_compress_avx512+0x11a/0x180 arch/x86/crypto/blake2s-core.S:234 Code: c1 c5 e1 ef d8 62 f1 65 08 72 c3 10 c5 e9 fe d3 c5 f1 ef ca 62 f1 75 08 72 c1 0c c4 43 7d 39 c9 01 c4 c1 79 fe c1 c5 f9 fe c1 e1 ef d8 62 f1 65 08 72 c3 08 c5 e9 fe d3 c5 f1 ef ca 62 f1 75 RSP: 0018:ffffc90000127648 EFLAGS: 00000282 RAX: ffffffff8dcdd940 RBX: 0000000000000001 RCX: 0000000000000003 RDX: 0000000000000001 RSI: ffffc90000127760 RDI: ffffc900001276f0 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 8d237cad860eee10 R12: ffffc90000127720 R13: ffffc900001276f0 R14: 0000000000000020 R15: ffffc90000127790 blake2s_compress+0x6e/0xe0 arch/x86/crypto/blake2s-glue.c:46 blake2s_final+0xc9/0x150 lib/crypto/blake2s.c:54 hmac.constprop.0+0x335/0x420 drivers/net/wireguard/noise.c:333 kdf.constprop.0+0x14b/0x280 drivers/net/wireguard/noise.c:367 mix_precomputed_dh drivers/net/wireguard/noise.c:426 [inline] wg_noise_handshake_create_initiation+0x3b0/0x650 drivers/net/wireguard/noise.c:560 wg_packet_send_handshake_initiation+0x19a/0x360 drivers/net/wireguard/send.c:34 wg_packet_handshake_send_worker+0x1c/0x30 drivers/net/wireguard/send.c:51 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10500 jiffies! g14497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27848 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 2984 Comm: kworker/u8:7 Not tainted 6.15.0-rc6-syzkaller-g088d13246a46 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x4aa/0x1290 kernel/smp.c:885 Code: 0c 00 85 ed 74 48 48 8b 44 24 20 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 7d 17 0c 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 de 0b 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0018:ffffc9000bdd7938 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853f740 RCX: ffffffff81af2ee9 RDX: ffff88803175a440 RSI: ffffffff81af2ec3 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170a7ee9 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b843b040 FS: 0000000000000000(0000) GS:ffff8881249df000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f37ad179ef8 CR3: 000000000e180000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2757 [inline] text_poke_bp_batch+0x220/0x760 arch/x86/kernel/alternative.c:2967 text_poke_flush arch/x86/kernel/alternative.c:3158 [inline] text_poke_flush arch/x86/kernel/alternative.c:3155 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:3165 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245