rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=1bcc/0/0x1 softirq=149321/149321 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20370/1:b..l rcu: (detected by 1, t=10502 jiffies, g=144677, q=203 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d e4 47 fb 0b 48 89 de 5b e9 73 90 5b 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 90 a2 92 65 8b 15 e8 81 RSP: 0018:ffffc90000007d00 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff88807b3fc300 RCX: 0000000080010003 RDX: ffffffff8de94e80 RSI: ffffffff8be09d40 RDI: ffffffff8be09d00 RBP: 0000000000000001 R08: ffffffff8fa2daf7 R09: 1ffffffff1f45b5e R10: dffffc0000000000 R11: fffffbfff1f45b5f R12: dffffc0000000000 R13: 0000000000000000 R14: ffff8880b8628380 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125bf7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f287c200000 CR3: 0000000057fe2000 CR4: 00000000003526f0 DR0: 0000000000000001 DR1: fffffffffffffff7 DR2: 0000000000000000 DR3: 000000000000000a DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:478 [inline] enqueue_hrtimer+0xaa/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 e3 8f 29 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: 00000000023b20b5 RBX: ffffffff8197762e RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d9a7514 RDI: ffffffff8be09d60 RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa2daf0 R13: 1ffffffff1bd29d0 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:759 start_kernel+0x386/0x3d0 init/main.c:1209 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.1.3694 state:R running task stack:25304 pid:20370 tgid:20369 ppid:17554 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 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:__sanitizer_cov_trace_pc+0x46/0x70 kernel/kcov.c:222 Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 44 16 00 00 00 74 2c 8b 91 20 16 00 00 83 fa 02 75 21 48 8b 91 28 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 24 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 RSP: 0018:ffffc9000be87340 EFLAGS: 00000246 RAX: ffffffff82338fa3 RBX: 000000000003a02a RCX: ffff88802a1abc80 RDX: ffffc9000d511000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc9000be874d0 R08: ffffffff8231eb0a R09: ffffffff8e144f60 R10: ffff88802a1ac558 R11: ffffffff81ad0f00 R12: 000000000003a02a R13: 0000000000000000 R14: 0000000000000000 R15: 000000000003a02a _static_cpu_has arch/x86/include/asm/cpufeature.h:101 [inline] __nr_to_section include/linux/mmzone.h:1958 [inline] __pfn_to_section include/linux/mmzone.h:2100 [inline] lookup_page_ext mm/page_ext.c:255 [inline] page_ext_lookup+0x163/0x180 mm/page_ext.c:513 page_ext_iter_begin include/linux/page_ext.h:132 [inline] __update_page_owner_handle+0x12f/0x570 mm/page_owner.c:256 __set_page_owner+0x10b/0x4c0 mm/page_owner.c:342 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x23d/0x2a0 mm/page_alloc.c:1887 prep_new_page mm/page_alloc.c:1895 [inline] get_page_from_freelist+0x23a5/0x2440 mm/page_alloc.c:3948 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5236 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1903 [inline] shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1945 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2540 shmem_get_folio mm/shmem.c:2646 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3299 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3474 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:688 ksys_write+0x145/0x250 fs/read_write.c:740 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: 0033:0x7f64e5b8e1ff RSP: 002b:00007f64e6966df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007f64e5b8e1ff RDX: 00000000013bd7ef RSI: 00007f64db800000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000054ff R10: 00000000000003c8 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f64e6966ef0 R14: 00007f64e6966eb0 R15: 00007f64db800000 rcu: rcu_preempt kthread starved for 10502 jiffies! g144677 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:26968 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 __schedule_loop kernel/sched/core.c:6976 [inline] schedule+0x165/0x360 kernel/sched/core.c:6991 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: 12 Comm: kworker/u8:0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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+0xcc5/0x1260 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b4 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5f 96 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 43 96 RSP: 0018:ffffc90000117760 EFLAGS: 00000293 RAX: ffffffff81b577ed RBX: 1ffff110170c85c1 RCX: ffff88801d2fdac0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900001178a0 R08: ffffffff8fa2daf7 R09: 1ffffffff1f45b5e R10: dffffc0000000000 R11: fffffbfff1f45b5f R12: ffff8880b8642e08 R13: dffffc0000000000 R14: ffff8880b873bd80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125cf7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000003e3030 CR3: 000000000df3e000 CR4: 00000000003526f0 DR0: 0000000000000001 DR1: fffffffffffffff7 DR2: 0000000000000000 DR3: 000000000000000a DR6: 00000000ffff0ff0 DR7: 0000000000000400 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:2746 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2956 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:879 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