rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=200701, q=705) rcu: All QSes seen, last rcu_preempt kthread activity 10496 (4295110131-4295099635), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10496 jiffies! g200701 f0x2 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:26768 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xc8d/0x1270 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 26925 Comm: syz-executor.5 Not tainted 5.15.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2599 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x3e/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:memcpy_erms+0x8/0x10 Code: cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 f3 a4 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe 7c 35 RSP: 0018:ffffc90000007bb8 EFLAGS: 00000202 RAX: ffffc90000007c00 RBX: ffffffff8827d6a0 RCX: 0000000000000000 RDX: 0000000000000028 RSI: ffff888183ff0460 RDI: ffffc90000007c28 RBP: ffffc90000007cb0 R08: dffffc0000000000 R09: fffff52000000f85 R10: fffff52000000f85 R11: 0000000000000000 R12: ffff888183ff0410 R13: ffffc90000007c00 R14: 0000000000000101 R15: 1ffff92000000f7c lockdep_copy_map include/linux/lockdep.h:35 [inline] call_timer_fn+0xac/0x210 kernel/time/timer.c:1411 expire_timers kernel/time/timer.c:1466 [inline] __run_timers+0x71a/0x910 kernel/time/timer.c:1734 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1747 __do_softirq+0x392/0x7a3 kernel/softirq.c:558 __irq_exit_rcu+0xec/0x170 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:finish_lock_switch+0xf0/0x1c0 kernel/sched/core.c:4695 Code: 81 0c 00 74 11 48 89 df be ff ff ff ff e8 98 ed 9d 08 85 c0 74 27 4d 85 ff 75 44 4c 89 f7 e8 67 90 a0 08 e8 a2 c3 2d 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 4d 85 ff 75 92 eb a8 0f 0b 4d RSP: 0018:ffffc90004d9f990 EFLAGS: 00000282 RAX: 19de6df9a7c5fc00 RBX: ffff888022139cb4 RCX: ffffffff81648061 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 1ffff11017386400 R08: dffffc0000000000 R09: fffffbfff1fa33df R10: fffffbfff1fa33df R11: 0000000000000000 R12: ffff8880b9c32000 R13: dffffc0000000000 R14: ffff8880b9c31540 R15: 0000000000000000 finish_task_switch+0x140/0x630 kernel/sched/core.c:4812 context_switch kernel/sched/core.c:4943 [inline] __schedule+0xc95/0x1270 kernel/sched/core.c:6287 preempt_schedule_common kernel/sched/core.c:6459 [inline] preempt_schedule+0x14d/0x190 kernel/sched/core.c:6484 preempt_schedule_thunk+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 perf_unpin_context kernel/events/core.c:1522 [inline] __do_sys_perf_event_open kernel/events/core.c:12380 [inline] __se_sys_perf_event_open+0x2fe3/0x4280 kernel/events/core.c:11987 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f26fe0718d9 Code: 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f26fb5e8188 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f26fe175f60 RCX: 00007f26fe0718d9 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000020000100 RBP: 00007f26fe0cbcb4 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd8e2a887f R14: 00007f26fb5e8300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: eb 1e jmp 0x22 4: 0f 1f 00 nopl (%rax) 7: 48 89 f8 mov %rdi,%rax a: 48 89 d1 mov %rdx,%rcx d: 48 c1 e9 03 shr $0x3,%rcx 11: 83 e2 07 and $0x7,%edx 14: f3 48 a5 rep movsq %ds:(%rsi),%es:(%rdi) 17: 89 d1 mov %edx,%ecx 19: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 1b: c3 retq 1c: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 22: 48 89 f8 mov %rdi,%rax 25: 48 89 d1 mov %rdx,%rcx 28: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) * 2a: c3 retq <-- trapping instruction 2b: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 32: 48 89 f8 mov %rdi,%rax 35: 48 83 fa 20 cmp $0x20,%rdx 39: 72 7e jb 0xb9 3b: 40 38 fe cmp %dil,%sil 3e: 7c 35 jl 0x75