rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=64f4/1/0x4000000000000000 softirq=65045/65046 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13075/1:b..l rcu: (detected by 1, t=10502 jiffies, g=70993, q=458 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__lock_acquire+0x11e/0x2630 kernel/locking/lockdep.c:5163 Code: c8 00 00 00 01 48 89 04 24 75 1f 48 8d b4 1d 68 0b 00 00 0f b7 46 20 25 ff 1f 00 00 44 39 e8 75 09 4d 85 e4 0f 85 99 05 00 00 <48> 8b 04 24 44 89 ea 66 81 e2 ff 1f 48 01 c3 0f b7 43 20 4c 89 53 RSP: 0000:ffffc90000007c80 EFLAGS: 00000046 RAX: ffff88801e2bb090 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888021f372c0 RBP: ffff88801e2ba500 R08: 0000000000000001 R09: 0000000000000001 R10: ffff888021f372c0 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000ecb R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124376000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc4f19af286 CR3: 000000002f67d000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158 spin_lock include/linux/spinlock.h:342 [inline] advance_sched+0xe5/0xd20 net/sched/sch_taprio.c:930 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206 Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 4a 85 57 f6 48 89 df e8 22 d5 57 f6 e8 7d db 83 f6 fb bf 01 00 00 00 72 a8 47 f6 65 8b 05 6b af 7d 08 85 c0 74 06 5b e9 51 4a 00 00 RSP: 0000:ffffc90000147b50 EFLAGS: 00000202 RAX: 00000000003c3ab6 RBX: ffff8880b8426340 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df1fe73 RDI: 0000000000000001 RBP: ffffffff81f4cfb0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90000147c20 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8426340 expire_timers kernel/time/timer.c:1798 [inline] __run_timers+0x74f/0xaf0 kernel/time/timer.c:2374 __run_timer_base kernel/time/timer.c:2386 [inline] __run_timer_base kernel/time/timer.c:2378 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2395 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1076 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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:26376 pid:13075 tgid:13075 ppid:13037 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:7462 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:753 rcu_read_unlock include/linux/rcupdate.h:867 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x745/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6246 [inline] kmem_cache_free+0x127/0x6c0 mm/slub.c:6373 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x228/0x8e0 mm/rmap.c:514 free_pgtables+0x2e7/0xd80 mm/memory.c:414 exit_mmap+0x44c/0xa10 mm/mmap.c:1312 __mmput+0x12a/0x410 kernel/fork.c:1178 mmput+0x67/0x80 kernel/fork.c:1201 exec_mmap fs/exec.c:893 [inline] begin_new_exec+0x10f0/0x3880 fs/exec.c:1148 load_elf_binary+0x8f1/0x51b0 fs/binfmt_elf.c:1010 search_binary_handler fs/exec.c:1664 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve fs/exec.c:1748 [inline] bprm_execve+0x8f5/0x1650 fs/exec.c:1724 do_execveat_common.isra.0+0x4a5/0x580 fs/exec.c:1846 __do_sys_execve fs/exec.c:1930 [inline] __se_sys_execve fs/exec.c:1924 [inline] __x64_sys_execve+0x93/0xd0 fs/exec.c:1924 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc4f18f5107 RSP: 002b:00007ffef8fc7a78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000055beff6f6e88 RCX: 00007fc4f18f5107 RDX: 000055beff6f6ea8 RSI: 000055beff6f6e88 RDI: 000055beff6f6f30 RBP: 000055beff6f6f30 R08: 00007ffef8fcbc20 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 000055beff6f6ea8 R13: 00007fc4f1abae8b R14: 000055beff6f6ea8 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10500 jiffies! g70993 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:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 1 UID: 0 PID: 13074 Comm: syz.2.1872 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: b6 5a 5c 00 48 89 df 5b e9 7d e5 61 00 be 03 00 00 00 5b e9 32 c2 f0 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 65 8b 05 05 16 02 12 48 8b 34 24 65 48 8b 15 e1 15 02 RSP: 0018:ffffc9000595fa78 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff81fc0dbd RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88804610ca00 RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0 FS: 00007f412b1e36c0(0000) GS:ffff888124476000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2a3d6f CR3: 0000000045dfe000 CR4: 00000000003526f0 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x587/0x1700 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 __sched_core_enable kernel/sched/core.c:475 [inline] sched_core_get+0x8a/0xa0 kernel/sched/core.c:499 sched_core_alloc_cookie kernel/sched/core_sched.c:20 [inline] sched_core_share_pid+0x406/0x9d0 kernel/sched/core_sched.c:187 __do_sys_prctl+0x6bd/0x2310 kernel/sys.c:2808 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f412a39cdd9 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:00007f412b1e3028 EFLAGS: 00000246 ORIG_RAX: 000000000000009d RAX: ffffffffffffffda RBX: 00007f412a615fa0 RCX: 00007f412a39cdd9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000003e RBP: 00007f412a432d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f412a616038 R14: 00007f412a615fa0 R15: 00007ffe72a66fc8