rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12925/1:b..l P1233/1:b..l rcu: (detected by 0, t=10502 jiffies, g=57137, q=1208 ncpus=2) task:kworker/0:2 state:R running task stack:21184 pid:1233 tgid:1233 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_power_efficient wg_ratelimiter_gc_entries Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 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+0x44/0x3d0 kernel/locking/lockdep.c:5879 Code: 8b 05 70 08 ae 10 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 73 08 ae 10 83 f8 08 0f 83 56 02 00 00 89 c0 48 0f a3 05 dc f5 c9 0d <73> 0d e8 65 12 09 00 84 c0 0f 84 94 02 00 00 83 3d f6 08 ca 0d 00 RSP: 0018:ffffc90005a279e8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff8e88d740 RCX: 0000000080000001 RDX: 000000006ecd90e7 RSI: ffffffff8b25ad5f RDI: ffffffff8ddcba80 RBP: 0000000000000001 R08: ffffffff8b25a1d0 R09: ffffffff8ddcba80 R10: 0000000000000000 R11: fffffbfff1ed4bb7 R12: 1ffff11005130c08 R13: ffffffff8b25ad5f R14: ffffffff8ddcba80 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:322 [inline] rcu_read_unlock include/linux/rcupdate.h:881 [inline] rt_spin_unlock+0x15b/0x200 kernel/locking/spinlock_rt.c:82 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:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 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 task:dhcpcd-run-hook state:R running task stack:28096 pid:12925 tgid:12925 ppid:12921 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7095 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:1896 [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] fast_dput+0xdd/0x430 fs/dcache.c:828 dput+0xe8/0x1a0 fs/dcache.c:924 path_put fs/namei.c:717 [inline] put_link+0x112/0x190 fs/namei.c:1196 walk_component fs/namei.c:2284 [inline] link_path_walk+0x1299/0x18d0 fs/namei.c:2644 path_openat+0x2d5/0x38a0 fs/namei.c:4826 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 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: 0033:0x7f7ff4696c3a RSP: 002b:00007ffcdb154b38 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7ff4696c3a RDX: 0000000000090800 RSI: 000055c7c0c240a0 RDI: 00000000ffffff9c RBP: 000055c7c0c2406f R08: 00007f7ff4772ac0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffcdb154c98 R13: 000055c7c0c24068 R14: 0000000000000001 R15: 000055c7c0c240c7 rcu: rcu_preempt kthread timer wakeup didn't happen for 10478 jiffies! g57137 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=43355 rcu: rcu_preempt kthread starved for 10479 jiffies! g57137 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27696 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 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: 12924 Comm: iou-sqp-12923 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] RIP: 0010:lock_acquire+0xf4/0x2e0 kernel/locking/lockdep.c:5870 Code: 0f 94 c1 4c 89 ef 8b 74 24 04 89 ea 44 89 e1 45 89 f8 6a 00 6a 00 6a 00 ff b4 24 88 00 00 00 41 56 e8 80 02 00 00 48 83 c4 28 <48> c7 c7 98 fa 7b 8d e8 b0 35 83 09 b8 ff ff ff ff 65 0f c1 05 83 RSP: 0018:ffffc900058872a0 EFLAGS: 00000096 RAX: 0000000000000001 RBX: 0000000000000246 RCX: 0000000000000000 RDX: 00000000a20aeead RSI: 00000000f18ba19c RDI: ffff88801e799e80 RBP: 0000000000000000 R08: ffffffff81767e65 R09: ffffffff8ddcba80 R10: ffffc90005887438 R11: ffffffff81af89e0 R12: 0000000000000002 R13: ffffffff8ddcba80 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fb90460e6c0(0000) GS:ffff888126439000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3c55df7ff8 CR3: 0000000088bfc000 CR4: 00000000003526f0 Call Trace: 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:2685 [inline] memcg_alloc_abort_single+0x102/0x230 mm/slub.c:6187 memcg_slab_post_alloc_hook mm/slub.c:2461 [inline] slab_post_alloc_hook mm/slub.c:4549 [inline] slab_alloc_node mm/slub.c:4866 [inline] __do_kmalloc_node mm/slub.c:5259 [inline] __kmalloc_noprof+0x48c/0x7b0 mm/slub.c:5272 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] io_alloc_ocqe+0xd4/0x620 io_uring/io_uring.c:667 io_cqe_overflow_locked+0x26/0x40 io_uring/io_uring.c:807 __io_submit_flush_completions+0x296/0xfc0 io_uring/io_uring.c:1141 io_submit_flush_completions io_uring/io_uring.h:238 [inline] io_submit_state_end io_uring/io_uring.c:1934 [inline] io_submit_sqes+0x1e40/0x2400 io_uring/io_uring.c:2058 __io_sq_thread io_uring/sqpoll.c:233 [inline] io_sq_thread+0xd03/0x1f70 io_uring/sqpoll.c:345 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245