rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=08bc/0/0x1 softirq=36441/36442 fqs=4 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5817/1:b..l P10876/1:b..l rcu: (detected by 1, t=10505 jiffies, g=36469, q=83 ncpus=2) 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(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:do_raw_spin_lock+0x187/0x290 kernel/locking/spinlock_debug.c:119 Code: 00 74 08 4c 89 e7 e8 08 e9 88 00 48 8b 44 24 10 49 89 04 24 48 c7 44 24 20 0e 36 e0 45 48 8b 44 24 18 4a c7 04 38 00 00 00 00 <65> 48 8b 05 d1 a8 02 11 48 3b 44 24 60 0f 85 e4 00 00 00 48 8d 65 RSP: 0018:ffffc90000007bc0 EFLAGS: 00000046 RAX: 1ffff92000000f7c RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007c00 RBP: ffffc90000007c80 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f80 R12: ffffffff99d4bc68 R13: ffffffff99d4bc60 R14: 1ffffffff33a978d R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125c0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c29feb7 CR3: 000000007ef06000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x4c/0x60 kernel/locking/spinlock.c:162 debug_object_activate+0x87/0x540 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x380 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x636/0xc30 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 43 8e 2b 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07dc0 EFLAGS: 000002c2 RAX: 00000000009081fb RBX: ffffffff819717be RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d99cce1 RDI: ffffffff8be082e0 RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa23d70 R13: 1ffffffff1bd29b8 R14: 0000000000000000 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x381/0x3d0 init/main.c:1206 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 task:syz.3.1706 state:R running task stack:26080 pid:10876 tgid:10875 ppid:5815 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7193 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 c0 ca be 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 da 48 03 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a8 c1 09 cc 48 8d 3d e7 8a 07 RSP: 0018:ffffc90003137418 EFLAGS: 00000286 RAX: 2ca25e6e09e74400 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005a44979c RSI: ffffffff8db80e95 RDI: ffffffff8be082e0 RBP: ffffffff8173fd85 R08: ffffffff8173fd85 R09: ffffffff8e13f2a0 R10: ffffc90003137578 R11: ffffffff81acb420 R12: 0000000000000002 R13: ffffffff8e13f2a0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:302 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1166 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 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: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:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1c0/0x660 mm/slub.c:6882 bpf_jit_binary_pack_finalize+0x49/0xf0 kernel/bpf/core.c:1183 bpf_int_jit_compile+0xaa6/0x14b0 arch/x86/net/bpf_jit_comp.c:3856 bpf_prog_select_runtime+0x4a3/0x820 kernel/bpf/core.c:2546 bpf_prog_load+0x13e9/0x1a10 kernel/bpf/syscall.c:3088 __sys_bpf+0x5c3/0x8a0 kernel/bpf/syscall.c:6203 __do_sys_bpf kernel/bpf/syscall.c:6316 [inline] __se_sys_bpf kernel/bpf/syscall.c:6314 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6314 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f717078f749 RSP: 002b:00007f7171692038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f71709e5fa0 RCX: 00007f717078f749 RDX: 0000000000000080 RSI: 0000200000000180 RDI: 0000000000000005 RBP: 00007f7170813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f71709e6038 R14: 00007f71709e5fa0 R15: 00007fff8615fd88 task:syz-executor state:R running task stack:19496 pid:5817 tgid:5817 ppid:5810 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1331 [inline] copy_pmd_range+0x74f2/0x7e00 mm/memory.c:1392 copy_pud_range mm/memory.c:1429 [inline] copy_p4d_range mm/memory.c:1453 [inline] copy_page_range+0xb88/0x11d0 mm/memory.c:1535 dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827 dup_mm kernel/fork.c:1529 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1581 copy_process+0x1812/0x3ba0 kernel/fork.c:2218 kernel_clone+0x21e/0x820 kernel/fork.c:2648 __do_sys_clone kernel/fork.c:2789 [inline] __se_sys_clone kernel/fork.c:2773 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc645d85e93 RSP: 002b:00007ffe679e88d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc645d85e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555934477d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000068422 R15: 00007ffe679e8a70 rcu: rcu_preempt kthread starved for 10485 jiffies! g36469 f0x0 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:28080 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297 kthread+0x389/0x480 kernel/kthread.c:467 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 2202 Comm: kworker/u8:10 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 64 ea fa 0b 48 89 de 5b e9 63 77 5b 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 40 a1 92 65 8b 15 68 84 e0 10 81 e2 00 01 ff 00 RSP: 0018:ffffc90005867758 EFLAGS: 00000202 RAX: ffffffff81b51d0d RBX: 1ffff110170c85c9 RCX: ffff88802a430000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900058678a0 R08: ffffffff8fa23d77 R09: 1ffffffff1f447ae R10: dffffc0000000000 R11: fffffbfff1f447af R12: ffff8880b8642e48 R13: dffffc0000000000 R14: ffff8880b873bdc0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125d0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9bfbecbd31 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xcdd/0x1260 kernel/smp.c:877 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2921 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:874 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x389/0x480 kernel/kthread.c:467 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246