rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10839 rcu: (detected by 1, t=10502 jiffies, g=38113, q=1745 ncpus=2) task:syz.1.2227 state:R running task stack:25320 pid:10839 tgid:10833 ppid:5633 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8180 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xfca/0x1380 kernel/rcu/tree_stall.h:680 check_cpu_stall kernel/rcu/tree_stall.h:855 [inline] rcu_pending kernel/rcu/tree.c:3708 [inline] rcu_sched_clock_irq+0x939/0x1050 kernel/rcu/tree.c:2744 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:296 [inline] tick_nohz_handler+0x3c6/0x6f0 kernel/time/tick-sched.c:317 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xb10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x455/0x950 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:rcu_lockdep_current_cpu_online+0xf1/0x120 kernel/rcu/tree.c:4079 Code: 86 00 4c 85 3b 75 1a 48 c7 c7 40 17 fd 8d be 04 00 00 00 e8 31 e3 86 00 83 3d 7a 94 52 0c 00 74 16 b0 01 65 ff 0d 5f fd cb 10 <74> 0f 5b 41 5e 41 5f e9 83 2a 8d 09 cc 31 c0 eb e8 e8 39 bc 88 ff RSP: 0018:ffffc90010ec77a0 EFLAGS: 00000286 RAX: 1ffffffff1bfa101 RBX: ffffffff8dfd0d70 RCX: 0000000080000001 RDX: 0000000000000002 RSI: ffffffff8baa5660 RDI: ffff8880b873cae8 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffffa02036e8 R12: ffff8880601edd2c R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000002 rcu_read_lock_held_common kernel/rcu/update.c:113 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 task_css_set include/linux/cgroup.h:509 [inline] task_dfl_cgroup include/linux/cgroup.h:578 [inline] ____bpf_get_current_ancestor_cgroup_id kernel/bpf/helpers.c:432 [inline] bpf_get_current_ancestor_cgroup_id+0x1ab/0x3f0 kernel/bpf/helpers.c:425 bpf_prog_d67dcd7642d7d92a+0x4e/0x54 bpf_dispatcher_nop_func include/linux/bpf.h:1454 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:422 bpf_prog_test_run_skb+0xe2c/0x2260 net/bpf/test_run.c:1229 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4859 __sys_bpf+0xa20/0xd90 kernel/bpf/syscall.c:6436 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline] __se_sys_bpf kernel/bpf/syscall.c:6534 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6534 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc51c23ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc51a48e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fc51c4b5fa0 RCX: 00007fc51c23ce59 RDX: 0000000000000050 RSI: 00002000000002c0 RDI: 000000000000000a RBP: 00007fc51c2d2d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc51c4b6038 R14: 00007fc51c4b5fa0 R15: 00007ffe4382ecf8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10450 jiffies! g38113 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1000 rcu: Possible timer handling issue on cpu=0 timer-softirq=17866 rcu: rcu_preempt kthread starved for 10451 jiffies! g38113 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1000 ->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:D stack:26912 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x172b/0x5550 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule_rtlock+0x30/0x70 kernel/sched/core.c:7386 rtlock_slowlock_locked+0x3635/0x3c80 kernel/locking/rtmutex.c:1894 rtlock_slowlock kernel/locking/rtmutex.c:1921 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] get_from_partial_node+0x58/0x470 mm/slub.c:3843 get_from_partial mm/slub.c:3973 [inline] ___slab_alloc+0xbb/0x910 mm/slub.c:4485 __slab_alloc_node mm/slub.c:4553 [inline] slab_alloc_node mm/slub.c:4932 [inline] kmem_cache_alloc_noprof+0x103/0x6c0 mm/slub.c:4955 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x156/0x580 lib/debugobjects.c:420 debug_objects_fill_pool+0x63/0x80 lib/debugobjects.c:780 debug_object_assert_init+0x65/0x300 lib/debugobjects.c:1058 debug_timer_assert_init kernel/time/timer.c:803 [inline] debug_assert_init kernel/time/timer.c:848 [inline] __try_to_del_timer_sync kernel/time/timer.c:1457 [inline] __timer_delete_sync+0x247/0x610 kernel/time/timer.c:1621 schedule_timeout+0x160/0x2c0 kernel/time/sleep_timeout.c:100 rcu_gp_fqs_loop+0x312/0x11b0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 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 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 6b 5c 02 e9 13 cc 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 93 91 15 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:ffffffff8dc07de0 EFLAGS: 00000246 RAX: 00000000000b8e69 RBX: ffffffff8199babc RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d65884b RDI: ffffffff8baa5680 RBP: ffffffff8dc07eb0 R08: ffff8880b8633d5b R09: 1ffff110170c67ab R10: dffffc0000000000 R11: ffffed10170c67ac R12: 0000000000000000 R13: 1ffffffff1b9fde8 R14: 1ffffffff1b80fc4 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125eb8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f45ff692a4f CR3: 000000002bd98000 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+0x1cc/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 rest_init+0x2de/0x300 init/main.c:717 start_kernel+0x392/0x3e0 init/main.c:1175 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/0x157