rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=a57/1/0x4000000000000000 softirq=27763/27766 fqs=0 (t=10500 jiffies g=34901 q=895) rcu: rcu_preempt kthread starved for 10500 jiffies! g34901 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:28016 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194 __try_to_del_timer_sync+0x193/0x1f0 kernel/time/timer.c:1369 __timer_delete_sync+0x1df/0x290 kernel/time/timer.c:1521 timer_delete_sync kernel/time/timer.c:1576 [inline] del_timer_sync include/linux/timer.h:200 [inline] schedule_timeout+0x18e/0x2d0 kernel/time/timer.c:2118 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 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: 13839 Comm: syz.2.2134 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4686 [inline] RIP: 0010:__lock_acquire+0x532/0x7d10 kernel/locking/lockdep.c:4962 Code: 81 e3 ff 1f 00 00 41 c1 ed 03 41 81 e5 f8 03 00 00 49 8d bd c0 40 1d 90 be 08 00 00 00 e8 c6 23 61 00 48 0f a3 1d 7e 36 c0 0e <73> 1f 48 8d 04 5b c1 e0 06 48 8d 98 80 bf b5 8f 48 ba 00 00 00 00 RSP: 0018:ffffc90000dd0a60 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000062 RCX: ffffffff815d0a3a RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d40c8 RBP: ffffc90000dd0cb0 R08: ffffffff901d40cf R09: 1ffffffff203a819 R10: dffffc0000000000 R11: fffffbfff203a81a R12: ffff88802cfa6450 R13: 0000000000000008 R14: 0000000000000000 R15: ffff88802cfa6430 FS: 00007fc3e752f6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6d996a8158 CR3: 0000000031ef5000 CR4: 00000000003506e0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162 hrtimer_interrupt+0xf8/0x8d0 kernel/time/hrtimer.c:1792 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline] RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:114 Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 d4 da c2 f7 e8 cf d8 c2 f7 fb 65 48 8b 05 b6 fb 45 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 11 db aa f7 48 RSP: 0018:ffffc9000335ff08 EFLAGS: 00000286 RAX: ffff88802cfa5940 RBX: 0000000000000049 RCX: f4facbe184333100 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc9000335ff48 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: 0000000000000000 R13: 0000000000000000 R14: ffffc9000335ff58 R15: 0000000000000000 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc3e92d5819 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:00007fc3e752f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000049 RAX: ffffffffffffffda RBX: 00007fc3e954efa0 RCX: 00007fc3e92d5819 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 RBP: 00007fc3e936bc91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc3e954f038 R14: 00007fc3e954efa0 R15: 00007ffd79c55a88 NMI backtrace for cpu 0 CPU: 0 PID: 13846 Comm: syz.3.2135 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x6ea/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline] RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:114 Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 d4 da c2 f7 e8 cf d8 c2 f7 fb 65 48 8b 05 b6 fb 45 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 11 db aa f7 48 RSP: 0018:ffffc9000339ff08 EFLAGS: 00000286 RAX: ffff888026e90000 RBX: 0000000000000027 RCX: 50727bbcc5079300 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc9000339ff48 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: 0000000000000000 R13: 0000000000000000 R14: ffffc9000339ff58 R15: 0000000000000000 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f702747a597 Code: 8d 3d 7c 8d 0b 00 e8 58 1d fa ff e8 a3 87 00 00 0f 1f 00 b8 68 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007f70256b8b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: ffffffffffffffda RBX: 00007f70256b8c70 RCX: 00007f702747a597 RDX: 00007f70256b8b40 RSI: 00007f70256b8c70 RDI: 0000000000000021 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f70276fa128 R14: 00007ffe2d83ed00 R15: 00007ffe2d83ede8