rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): (detected by 0, t=10502 jiffies, g=356201, q=16015) rcu: All QSes seen, last rcu_preempt kthread activity 7574 (4295187483-4295179909), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread timer wakeup didn't happen for 7573 jiffies! g356201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=135617 rcu: rcu_preempt kthread starved for 7574 jiffies! g356201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28800 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4339 [inline] __schedule+0x916/0x23e0 kernel/sched/core.c:5147 schedule+0xcf/0x270 kernel/sched/core.c:5226 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892 rcu_gp_fqs_loop kernel/rcu/tree.c:2004 [inline] rcu_gp_kthread+0xd07/0x2300 kernel/rcu/tree.c:2177 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 20100 Comm: syz-executor.2 Not tainted 5.13.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1cc/0x1d1 kernel/rcu/tree_stall.h:478 print_other_cpu_stall kernel/rcu/tree_stall.h:583 [inline] check_cpu_stall kernel/rcu/tree_stall.h:708 [inline] rcu_pending kernel/rcu/tree.c:3911 [inline] rcu_sched_clock_irq+0x1d46/0x2080 kernel/rcu/tree.c:2649 update_process_times+0x16d/0x200 kernel/time/timer.c:1796 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1373 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:325 [inline] RIP: 0010:rcu_is_watching+0x3f/0xc0 kernel/rcu/tree.c:1168 Code: 83 f8 07 89 c5 0f 87 81 00 00 00 48 8d 3c ed e0 66 0e 8b 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5b <48> 03 1c ed e0 66 0e 8b 48 b8 00 00 00 00 00 fc ff df 48 8d bb 48 RSP: 0018:ffffc9001f6b76c0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000036080 RCX: 000000003dfe94e6 RDX: 1ffffffff161ccdc RSI: 0000000000000002 RDI: ffffffff8b0e66e0 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff902258a7 R10: fffffbfff2044b14 R11: 0000000000000000 R12: ffffea00008105c8 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea00008105c0 rcu_read_lock include/linux/rcupdate.h:658 [inline] lock_page_memcg+0x51e/0x7d0 mm/memcontrol.c:1982 page_remove_rmap+0x25/0x1430 mm/rmap.c:1348 zap_pte_range mm/memory.c:1270 [inline] zap_pmd_range mm/memory.c:1374 [inline] zap_pud_range mm/memory.c:1403 [inline] zap_p4d_range mm/memory.c:1424 [inline] unmap_page_range+0xe30/0x2650 mm/memory.c:1445 unmap_single_vma+0x198/0x300 mm/memory.c:1490 unmap_vmas+0x16d/0x2f0 mm/memory.c:1522 exit_mmap+0x2a8/0x590 mm/mmap.c:3208 __mmput+0x122/0x470 kernel/fork.c:1096 mmput+0x58/0x60 kernel/fork.c:1117 exit_mm kernel/exit.c:502 [inline] do_exit+0xb0a/0x2a60 kernel/exit.c:813 do_group_exit+0x125/0x310 kernel/exit.c:923 get_signal+0x47f/0x2150 kernel/signal.c:2818 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x171/0x280 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 Code: Unable to access opcode bytes at RIP 0x4665af. RSP: 002b:00007f14a5bed218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf68 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf68 RBP: 000000000056bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf6c R13: 0000000000a9fb1f R14: 00007f14a5bed300 R15: 0000000000022000