rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=10001, q=71 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294957733-4294947231), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g10001 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+0x10e9/0x40d0 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: 4279 Comm: syz-executor382 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x8b/0x100 kernel/locking/spinlock.c:194 Code: 83 c7 18 48 8b 75 08 e8 83 d1 49 f7 4c 89 f7 e8 db 96 4a f7 f7 c3 00 02 00 00 74 05 e8 ce 97 6d f7 48 c7 44 24 20 00 00 00 00 <9c> 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf RSP: 0018:ffffc900001e0bc0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000806 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880754540c0 RBP: ffffc900001e0c40 R08: dffffc0000000000 R09: ffffed100ea8a819 R10: ffffed100ea8a819 R11: 1ffff1100ea8a818 R12: dffffc0000000000 R13: ffff888030f30918 R14: ffff8880754540c0 R15: 1ffff9200003c178 FS: 000055557bba03c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2f09b6ff10 CR3: 000000002b59c000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:753 [inline] send_sigqueue+0x3ee/0x600 kernel/signal.c:2008 posix_timer_event kernel/time/posix-timers.c:360 [inline] posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386 __run_hrtimer kernel/time/hrtimer.c:1752 [inline] __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1816 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1878 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 de d0 49 f7 48 89 df e8 36 96 4a f7 e8 31 97 6d f7 fb bf 01 00 00 00 46 13 3e f7 65 8b 05 17 d4 e8 75 85 c0 74 02 5b c3 e8 64 e5 e6 RSP: 0018:ffffc90003d67bb8 EFLAGS: 00000286 RAX: 9714e63300eb6f00 RBX: ffff8880754540c0 RCX: 9714e63300eb6f00 RDX: dffffc0000000000 RSI: ffffffff8a6bffe0 RDI: 0000000000000001 RBP: ffff888075454558 R08: dffffc0000000000 R09: ffffed100ea8a819 R10: ffffed100ea8a819 R11: 1ffff1100ea8a818 R12: 1ffff1100ea8a8ab 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: 0033:0x7f2f09b58899 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 19 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:00007ffea2226d58 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f2f09b58899 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 00007f2f09b18990 R09: 00007f2f09b18990 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2f09bb633c R13: 00007f2f09bb0106 R14: 00007ffea2226d90 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.108 msecs