rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=11653, q=19) rcu: All QSes seen, last rcu_preempt kthread activity 10500 (4294959403-4294948903), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10500 jiffies! g11653 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:25688 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 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: NMI backtrace for cpu 1 CPU: 1 PID: 4763 Comm: syz.2.107 Not tainted 5.15.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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:should_resched arch/x86/include/asm/preempt.h:103 [inline] RIP: 0010:__local_bh_enable_ip+0x16c/0x1f0 kernel/softirq.c:390 Code: 8a e8 28 29 f1 08 65 66 8b 05 30 0e b6 7e 66 85 c0 75 57 bf 01 00 00 00 e8 01 f2 09 00 e8 4c 67 39 00 fb 65 8b 05 1c e5 b4 7e <85> c0 75 05 e8 eb 01 b3 ff 48 c7 44 24 20 0e 36 e0 45 49 c7 04 1c RSP: 0018:ffffc9000321f9e0 EFLAGS: 00000282 RAX: 0000000080000000 RBX: 1ffff92000643f40 RCX: ffffffff96a8ef03 RDX: dffffc0000000000 RSI: ffffffff8aab2a80 RDI: ffffffff8af9ed00 RBP: ffffc9000321fa90 R08: ffffffff8186f220 R09: ffffed1027fe3e41 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff92000643f44 R14: ffffc9000321fa20 R15: 0000000000000200 fpregs_unlock arch/x86/include/asm/fpu/api.h:78 [inline] restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:300 [inline] __fpu_restore_sig arch/x86/kernel/fpu/signal.c:334 [inline] fpu__restore_sig+0x841/0x1100 arch/x86/kernel/fpu/signal.c:466 restore_sigcontext+0x638/0x710 arch/x86/kernel/signal.c:139 __do_sys_rt_sigreturn+0x190/0x250 arch/x86/kernel/signal.c:674 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f08566376d0 Code: 10 83 e0 01 83 e2 01 88 15 1a 50 e3 00 88 05 17 50 e3 00 c3 50 48 8d 35 00 36 1b 00 48 8d 3d 06 36 1b 00 31 c0 e8 30 f7 ff ff <53> 89 fb 48 83 ec 10 64 8b 04 25 94 ff ff ff 85 c0 74 2a 89 fe 31 RSP: 002b:00007f08545aa678 EFLAGS: 00000287 RAX: 0000000000000000 RBX: 6666666666666667 RCX: 0000000000000000 RDX: 00007f08545aa680 RSI: 00007f08545aa7b0 RDI: 000000000000000b RBP: 00007f08545aac30 R08: 00000000000003ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000101301 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f085693d160 R15: 00007fffbe0da328