rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29/3:b..l P5818/1:b..l rcu: (detected by 0, t=10502 jiffies, g=48577, q=288 ncpus=2) task:kworker/0:4 state:R running task stack:22056 pid:5818 tgid:5818 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_power_efficient wg_ratelimiter_gc_entries Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x1681/0x54c0 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2dc/0x3c0 kernel/locking/lockdep.c:5893 Code: 00 00 eb b5 e8 45 06 8a 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 25 d1 d0 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 5b 41 5c 41 5d <41> 5e 41 5f 5d e9 4a c9 8d 09 cc 48 8d 3d 32 16 ee 0d 67 48 0f b9 RSP: 0018:ffffc90004327a30 EFLAGS: 00000286 RAX: 10c97a57c9625f00 RBX: ffffffff8ea98960 RCX: 0000000000000046 RDX: 000000005633614f RSI: ffffffff8d891dd8 RDI: ffffffff8ba73060 RBP: ffff88803a3b49c8 R08: ffffffff8b2cf750 R09: ffffffff8dfc80c0 R10: 0000000000000000 R11: fffffbfff1f1717f R12: ffff88805e0ab7f8 R13: ffffffff8ea98ac0 R14: ffffffff8ea989b8 R15: ffff88803a3b3d80 rt_spin_unlock+0x29/0x200 kernel/locking/spinlock_rt.c:80 spin_unlock include/linux/spinlock_rt.h:109 [inline] wg_ratelimiter_gc_entries+0x3a8/0x480 drivers/net/wireguard/ratelimiter.c:76 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:ktimers/1 state:R running task stack:21976 pid:29 tgid:29 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x1681/0x54c0 kernel/sched/core.c:7188 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7369 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 class_preempt_destructor include/linux/preempt.h:468 [inline] raw_spin_unlock_irqrestore_wake include/linux/sched/wake_q.h:102 [inline] rtlock_slowlock kernel/locking/rtmutex.c:1912 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x316/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] get_random_u32+0x1e0/0x860 drivers/char/random.c:541 __get_random_u32_below+0x14/0x90 drivers/char/random.c:555 get_random_u32_below include/linux/random.h:63 [inline] mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x5b0/0x7f0 net/802/mrp.c:612 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x6a3/0x9f0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 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 rcu: rcu_preempt kthread starved for 10502 jiffies! g48577 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:27512 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x1681/0x54c0 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 2b 63 02 e9 43 c7 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 ca 1e 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8dc07dc0 EFLAGS: 00000242 RAX: 000000000077c8fd RBX: ffffffff819980da RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d63094a RDI: ffffffff8ba73060 RBP: ffffffff8dc07eb0 R08: ffff8880b8833e9b R09: 1ffff110171067d3 R10: dffffc0000000000 R11: ffffed10171067d4 R12: 0000000000000000 R13: 1ffffffff1b9fdd8 R14: 0000000000000000 R15: 1ffffffff1b9fdd8 FS: 0000000000000000(0000) GS:ffff888126109000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f39bc4cba40 CR3: 000000005e926000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 rest_init+0x2de/0x300 init/main.c:762 start_kernel+0x38a/0x3e0 init/main.c:1220 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147