rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=10465, q=84 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294959005-4294948502), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g10465 f0x2 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:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4475 Comm: syz.1.27 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__lock_acquire+0x1066/0x7c50 kernel/locking/lockdep.c:4957 Code: 8d 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85 b4 5a 00 00 41 01 de 83 3d 30 2b 9c 0c 00 4c 8b bc 24 c0 00 00 00 0f 85 02 03 00 00 <48> 83 7c 24 60 00 0f 84 39 02 00 00 48 8b 44 24 78 48 8d 58 f8 48 RSP: 0018:ffffc90000007860 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 00000000c373506c RCX: 00000000762add5d RDX: 00000000f8b7e1cf RSI: 00000000f588fa50 RDI: ffffffff908c8240 RBP: ffffc90000007ab0 R08: dffffc0000000000 R09: fffffbfff2119049 R10: fffffbfff2119049 R11: 1ffffffff2119048 R12: 00000000cf82e703 R13: 00000000c2fd2ede R14: 00000000b144b952 R15: ffff88801d320ad0 FS: 00007f9fe155a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 0000000077b07000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x63/0x340 lib/debugobjects.c:753 debug_hrtimer_deactivate kernel/time/hrtimer.c:453 [inline] debug_deactivate+0x29/0x240 kernel/time/hrtimer.c:509 __run_hrtimer kernel/time/hrtimer.c:1715 [inline] __hrtimer_run_queues+0x2df/0xd60 kernel/time/hrtimer.c:1811 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 05 49 f7 48 89 df e8 06 cb 49 f7 e8 d1 bd 6c f7 fb bf 01 00 00 00 96 43 3d f7 65 8b 05 27 f1 e7 75 85 c0 74 02 5b c3 e8 c4 02 e6 RSP: 0018:ffffc90003697b98 EFLAGS: 00000282 RAX: 6db2097ac0634000 RBX: ffff888024999280 RCX: 6db2097ac0634000 RDX: dffffc0000000000 RSI: ffffffff8a6c0600 RDI: 0000000000000001 RBP: ffff888024999718 R08: dffffc0000000000 R09: ffffed1004933251 R10: ffffed1004933251 R11: 1ffff11004933250 R12: 1ffff110049332e3 R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1163/0x1350 kernel/signal.c:2874 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9fe078f747 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007f9fe155a0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f9fe09e5fa8 RCX: 00007f9fe078f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9fe09e5fa8 RBP: 00007f9fe09e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9fe09e6038 R14: 00007fffc06c2c50 R15: 00007fffc06c2d38 sched: RT throttling activated