rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27993/1:b..l rcu: (detected by 1, t=10503 jiffies, g=150553, q=471 ncpus=2) task:syz.3.4754 state:R running task stack:26168 pid:27993 tgid:27991 ppid:27644 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7095 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] zap_pte_range mm/memory.c:1959 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x152f/0x4840 mm/memory.c:2091 unmap_single_vma+0x153/0x240 mm/memory.c:2133 unmap_vmas+0x295/0x590 mm/memory.c:2171 exit_mmap+0x1ef/0xa30 mm/mmap.c:1302 __mmput+0x12a/0x410 kernel/fork.c:1175 mmput+0x67/0x80 kernel/fork.c:1198 exit_mm kernel/exit.c:581 [inline] do_exit+0x819/0x2b60 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f338f79c819 RSP: 002b:00007f338d9d5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f338fa16090 RCX: 00007f338f79c819 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f338f832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f338fa16128 R14: 00007f338fa16090 R15: 00007ffedd3532d8 rcu: rcu_preempt kthread starved for 10533 jiffies! g150553 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:27976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 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+0x754/0xd80 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: 28015 Comm: syz.8.4761 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline] RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline] RIP: 0010:native_apic_msr_write arch/x86/include/asm/apic.h:208 [inline] RIP: 0010:native_apic_msr_write+0x28/0x40 arch/x86/include/asm/apic.h:202 Code: 90 90 f3 0f 1e fa 8d 87 30 ff ff ff 83 e0 ef 74 20 89 f8 83 e0 ef 83 f8 20 74 16 c1 ef 04 31 d2 89 f0 8d 8f 00 08 00 00 0f 30 <66> 90 c3 cc cc cc cc c3 cc cc cc cc 89 f6 31 d2 89 cf e9 11 ed 75 RSP: 0018:ffffc90000007ec8 EFLAGS: 00000046 RAX: 000000000002bf10 RBX: ffff8880b8423f80 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 000000000002bf10 RDI: 0000000000000038 RBP: 000000000002bf10 R08: 0000000000000005 R09: 000000000000003f R10: 0000000000000020 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000020 R15: ffff8880b84284c0 FS: 00007fc6267f66c0(0000) GS:ffff888124339000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc628817dac CR3: 0000000070189000 CR4: 00000000003526f0 Call Trace: apic_write arch/x86/include/asm/apic.h:405 [inline] lapic_next_event+0x10/0x20 arch/x86/kernel/apic/apic.c:418 clockevents_program_event+0x26e/0x360 kernel/time/clockevents.c:334 tick_program_event+0xa9/0x140 kernel/time/tick-oneshot.c:48 hrtimer_interrupt+0x3e9/0x8c0 kernel/time/hrtimer.c:1924 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x109/0x490 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:futex_setup_timer+0x1e/0xf0 kernel/futex/core.c:466 Code: 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 55 49 89 cd 41 54 49 89 fc 55 89 d5 53 48 89 f3 48 83 ec 08 e8 42 bb 0d 00 <4d> 85 e4 0f 84 9e 00 00 00 e8 34 bb 0d 00 83 e5 20 31 ff 89 ee e8 RSP: 0018:ffffc9000462fc40 EFLAGS: 00000246 RAX: 0000000000080000 RBX: ffffc9000462fcb0 RCX: ffffc9000f923000 RDX: 0000000000080000 RSI: ffffffff81fb41de RDI: 0000000000000000 RBP: 0000000000000002 R08: 00000000ffffffff R09: 000000000000000d R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88808cb0c980 futex_wait+0xd2/0x380 kernel/futex/waitwake.c:712 do_futex+0x1ef/0x350 kernel/futex/syscalls.c:130 __do_sys_futex kernel/futex/syscalls.c:207 [inline] __se_sys_futex kernel/futex/syscalls.c:188 [inline] __x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:188 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc62859c819 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:00007fc6267f60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fc628815fa8 RCX: 00007fc62859c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc628815fa8 RBP: 00007fc628815fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc628816038 R14: 00007ffec5a3f150 R15: 00007ffec5a3f238