rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=24b4/1/0x4000000000000000 softirq=22362/22364 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=17117, q=45 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6432 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319 Code: 48 8d 3d 63 a8 2b 04 48 c7 c6 4a fc 77 8d 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 31 c0 83 3d e7 5d 28 04 00 74 1e 83 3d fa 8c 28 04 00 RSP: 0018:ffffc90000a08c68 EFLAGS: 00000082 RAX: ffffffff89374057 RBX: ffffffff89709198 RCX: ffff88802c938000 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 0000000000000001 R08: ffff88807b8aa19f R09: 1ffff1100f715433 R10: dffffc0000000000 R11: ffffed100f715434 R12: ffff88807b8aa320 R13: ffff88807b8aa000 R14: 18893727e68a6a24 R15: ffff88807fb42400 FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7c5a1f5d58 CR3: 000000007597f000 CR4: 0000000000350ef0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:895 [inline] advance_sched+0xa9f/0xc90 net/sched/sch_taprio.c:993 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x51c/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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 Code: f7 e8 cd 3a 42 f6 f7 c3 00 02 00 00 74 05 e8 40 69 6c f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 04 55 34 f6 65 8b 05 0d b8 23 07 85 c0 74 18 5b 41 5e e9 dc e8 RSP: 0018:ffffc900038772a8 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000000000006 RSI: ffffffff8d79263f RDI: 0000000000000001 RBP: ffffc900038773b0 R08: ffffffff8f822377 R09: 1ffffffff1f0446e R10: dffffc0000000000 R11: fffffbfff1f0446f R12: ffffc90003877420 R13: ffffc90003877518 R14: ffff88801bee8098 R15: 000000000000001f spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1481 [inline] folios_put_refs+0x51a/0x670 mm/swap.c:994 free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline] tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 exit_mmap+0x439/0xb10 mm/mmap.c:1290 __mmput+0x118/0x430 kernel/fork.c:1173 exec_mmap+0x3b5/0x440 fs/exec.c:901 begin_new_exec+0x1353/0x2440 fs/exec.c:1156 load_elf_binary+0x998/0x2740 fs/binfmt_elf.c:1010 search_binary_handler fs/exec.c:1669 [inline] exec_binprm fs/exec.c:1701 [inline] bprm_execve+0x92e/0x1400 fs/exec.c:1753 do_execveat_common+0x510/0x6a0 fs/exec.c:1859 do_execve fs/exec.c:1933 [inline] __do_sys_execve fs/exec.c:2009 [inline] __se_sys_execve fs/exec.c:2004 [inline] __x64_sys_execve+0x94/0xb0 fs/exec.c:2004 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: 0033:0x7fcc4ec95107 Code: Unable to access opcode bytes at 0x7fcc4ec950dd. RSP: 002b:00007ffffcf93ad8 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000055761647e078 RCX: 00007fcc4ec95107 RDX: 000055761647e0a0 RSI: 000055761647e078 RDI: 000055761647e130 RBP: 000055761647e130 R08: 00007ffffcf97eb9 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 000055761647e0a0 R13: 00007fcc4ee5ae8b R14: 000055761647e0a0 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10505 jiffies! g17117 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:27760 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 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: 0 UID: 0 PID: 1104 Comm: kworker/u8:7 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:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xcca/0x1260 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 e4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 8f 93 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 73 93 0b 00 eb e4 44 RSP: 0018:ffffc90003f0f6a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170e8129 RCX: ffff888026fe9e80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003f0f7e0 R08: ffffffff8f822377 R09: 1ffffffff1f0446e R10: dffffc0000000000 R11: fffffbfff1f0446f R12: ffff8880b8740948 R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7c5a1f4f98 CR3: 000000000dd3a000 CR4: 0000000000350ef0 Call Trace: 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 kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246