rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=029/1/0x4000000000000000 softirq=42345/42345 fqs=25 (t=10500 jiffies g=54853 q=668) rcu: rcu_preempt kthread starved for 10449 jiffies! g54853 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:27168 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12883 Comm: syz.4.2019 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pvclock_clocksource_read+0x1eb/0x760 arch/x86/kernel/pvclock.c:77 Code: b6 04 20 84 c0 48 8b 54 24 38 4c 8b 74 24 28 0f 85 bf 02 00 00 49 8b 2a 48 8b 44 24 58 42 0f b6 04 20 84 c0 0f 85 06 03 00 00 <44> 0f b6 7f 1d 42 0f b6 04 22 84 c0 0f 85 4f 03 00 00 43 0f b6 04 RSP: 0018:ffffc90000007dd0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 000000000000000a RCX: 0000000000000001 RDX: 1ffffffff1dda000 RSI: ffffffff8eed001c RDI: ffffffff8eed0000 RBP: 000000003031c1c7 R08: ffffffff8eed0008 R09: ffffffff8eed0018 R10: ffffffff8eed0010 R11: ffffffff8eed0003 R12: dffffc0000000000 R13: 0000009f2524f829 R14: 1ffffffff1dda000 R15: ffffffff8bbc1820 FS: 00007fdeba0e46c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000002461e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_clock_read arch/x86/kernel/kvmclock.c:79 [inline] kvm_sched_clock_read+0x14/0x40 arch/x86/kernel/kvmclock.c:91 sched_clock_cpu+0x15/0x3c0 kernel/sched/clock.c:371 irqtime_account_irq+0x6a/0x1b0 kernel/sched/cputime.c:61 account_hardirq_exit include/linux/vtime.h:159 [inline] __irq_exit_rcu+0x8d/0x220 kernel/softirq.c:656 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 1d aa f7 48 89 df e8 56 f2 aa f7 e8 d1 8c cb f7 fb bf 01 00 00 00 a6 15 9f f7 65 8b 05 a7 13 50 76 85 c0 74 02 5b c3 e8 54 1e 4e RSP: 0018:ffffc900032bfbc0 EFLAGS: 00000282 RAX: 5e2ab341d5f5ea00 RBX: ffff88801f626f00 RCX: 5e2ab341d5f5ea00 RDX: dffffc0000000000 RSI: ffffffff8a0b1620 RDI: 0000000000000001 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed1003ec4de1 R10: ffffed1003ec4de1 R11: 1ffff11003ec4de0 R12: ffff88801f626f00 R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x11d6/0x12c0 kernel/signal.c:2903 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fdebbe7cbe7 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:00007fdeba0e40e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007fdebc0b3fa8 RCX: 00007fdebbe7cbe9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdebc0b3fa8 RBP: 00007fdebc0b3fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdebc0b4038 R14: 00007ffe364bd140 R15: 00007ffe364bd228 NMI backtrace for cpu 1 CPU: 1 PID: 12869 Comm: syz.9.2013 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 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+0x6d8/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 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:1690 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 1d aa f7 48 89 df e8 56 f2 aa f7 e8 d1 8c cb f7 fb bf 01 00 00 00 a6 15 9f f7 65 8b 05 a7 13 50 76 85 c0 74 02 5b c3 e8 54 1e 4e RSP: 0018:ffffc90002eafbc0 EFLAGS: 00000282 RAX: 5374dee78020ad00 RBX: ffff88801f621bc0 RCX: 5374dee78020ad00 RDX: dffffc0000000000 RSI: ffffffff8a0b1620 RDI: 0000000000000001 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed1003ec4379 R10: ffffed1003ec4379 R11: 1ffff11003ec4378 R12: ffff88801f621bc0 R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x11d6/0x12c0 kernel/signal.c:2903 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f66cd915be7 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:00007f66cbb7d0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f66cdb4cfa8 RCX: 00007f66cd915be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f66cdb4cfa8 RBP: 00007f66cdb4cfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f66cdb4d038 R14: 00007ffc41fdcdf0 R15: 00007ffc41fdced8