rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=8385, q=42 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294956717-4294946214), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g8385 f0x2 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: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:1965 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4300 Comm: syz-executor228 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:596 [inline] RIP: 0010:queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline] RIP: 0010:do_raw_spin_unlock+0x10f/0x230 kernel/locking/spinlock_debug.c:141 Code: ff ff ff ff 48 c7 c0 00 b2 99 8c 48 c1 e8 03 42 80 3c 20 00 74 0c 48 c7 c7 00 b2 99 8c e8 a9 b1 6c 00 48 83 3d 41 80 35 0b 00 <0f> 84 0f 01 00 00 48 89 df e8 b3 13 bc 08 90 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900001e0dc8 EFLAGS: 00000082 RAX: 1ffffffff1933640 RBX: ffff8880b8f2a580 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880b8f2a580 RBP: 1ffff110171e54b1 R08: dffffc0000000000 R09: ffffed10171e54b1 R10: ffffed10171e54b1 R11: 1ffff110171e54b0 R12: dffffc0000000000 R13: 1ffff110171e54b2 R14: ffff8880b8f2a590 R15: ffff8880b8f2a588 FS: 0000555576dd53c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f53653d6a20 CR3: 000000007e515000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x75/0x100 kernel/locking/spinlock.c:194 hrtimer_interrupt+0x593/0x9c0 kernel/time/hrtimer.c:1888 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 2e 31 43 f7 48 89 df e8 86 f6 43 f7 e8 91 e8 66 f7 fb bf 01 00 00 00 36 74 37 f7 65 8b 05 07 35 e2 75 85 c0 74 02 5b c3 e8 54 46 e0 RSP: 0018:ffffc90003df7bb8 EFLAGS: 00000286 RAX: 3c05483738880400 RBX: ffff88802f1d2500 RCX: 3c05483738880400 RDX: dffffc0000000000 RSI: ffffffff8a8c0460 RDI: 0000000000000001 RBP: ffff88802f1d2998 R08: dffffc0000000000 R09: ffffed1005e3a4a1 R10: ffffed1005e3a4a1 R11: 1ffff11005e3a4a0 R12: 1ffff11005e3a533 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+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 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: 0033:0x7f53653bd849 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 1d 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffefb446428 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f53653bd849 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 00007f5365375990 R09: 00007f5365375990 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f536541405c R13: 00007f536540d10f R14: 00007ffefb446460 R15: 0000000000000000