rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10446 ticks this GP) idle=c0a/1/0x4000000000000000 softirq=11160/11165 fqs=225 (t=10502 jiffies g=11097 q=636) rcu: rcu_preempt kthread starved for 4193 jiffies! g11097 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:29176 pid: 11 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3779 [inline] __schedule+0x893/0x2130 kernel/sched/core.c:4528 schedule+0xcf/0x270 kernel/sched/core.c:4606 schedule_timeout+0x148/0x250 kernel/time/timer.c:1871 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline] rcu_gp_kthread+0xb4c/0x1c90 kernel/rcu/tree.c:2099 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 NMI backtrace for cpu 0 CPU: 0 PID: 10177 Comm: syz-executor702 Not tainted 5.10.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 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_dump_cpu_stacks+0x1e3/0x21e kernel/rcu/tree_stall.h:331 print_cpu_stall kernel/rcu/tree_stall.h:563 [inline] check_cpu_stall kernel/rcu/tree_stall.h:637 [inline] rcu_pending kernel/rcu/tree.c:3694 [inline] rcu_sched_clock_irq.cold+0x472/0xee8 kernel/rcu/tree.c:2567 update_process_times+0x77/0xd0 kernel/time/timer.c:1709 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1519 [inline] __hrtimer_run_queues+0x1ce/0xea0 kernel/time/hrtimer.c:1583 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1645 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1097 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:91 [inline] sysvec_apic_timer_interrupt+0x48/0x100 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:slab_alloc_node mm/slub.c:2832 [inline] RIP: 0010:slab_alloc mm/slub.c:2899 [inline] RIP: 0010:kmem_cache_alloc+0x138/0x440 mm/slub.c:2904 Code: c6 c7 35 b1 81 48 c7 c7 e0 78 33 8b e8 21 ef a4 ff 45 31 ed e9 bd 00 00 00 45 31 f6 48 85 ed 74 f0 48 8b 45 00 65 48 8b 50 08 <48> 89 c1 65 48 03 0d 65 5f 50 7e 48 8b 71 08 48 39 f2 75 e7 48 8b RSP: 0018:ffffc90000007990 EFLAGS: 00000286 RAX: 0000607f45e04f00 RBX: ffff88802794e480 RCX: ffffffff86f55f43 RDX: 0000000000004560 RSI: 00000000000000e8 RDI: ffffffff8b45ada0 RBP: ffff88802075c500 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000a20 R13: ffffffff86f55b1e R14: 0000000000000000 R15: 0000000000000a20 dst_alloc+0x9e/0x650 net/core/dst.c:93 ip6_dst_alloc+0x2e/0x100 net/ipv6/route.c:356 icmp6_dst_alloc+0x6d/0x6c0 net/ipv6/route.c:3167 ndisc_send_skb+0x1207/0x1720 net/ipv6/ndisc.c:488 ndisc_send_rs+0x12e/0x700 net/ipv6/ndisc.c:702 addrconf_rs_timer+0x3f2/0x820 net/ipv6/addrconf.c:3873 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1410 expire_timers kernel/time/timer.c:1455 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1747 __run_timers kernel/time/timer.c:1728 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1760 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x132/0x200 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:call_rcu+0x2e7/0x700 kernel/rcu/tree.c:3028 Code: 3c 02 00 0f 85 bb 03 00 00 48 8b 05 53 98 d6 09 49 03 84 24 f0 00 00 00 49 39 c7 0f 8f 65 01 00 00 e8 0d 63 18 00 ff 34 24 9d <48> 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 80 3c 02 00 0f 84 2f RSP: 0018:ffffc9000b1cf7c8 EFLAGS: 00000246 RAX: 0000000000138ecb RBX: ffff88801c6d2e08 RCX: ffffffff8155a937 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8880b9e35830 R08: 0000000000000001 R09: ffffffff8ebaf67f R10: fffffbfff1d75ecf R11: 1ffffffff1ced6ef R12: ffff8880b9e35740 R13: ffff8880b9e35820 R14: ffff8880b9e357d8 R15: 0000000000000004 put_task_struct_rcu_user+0x7f/0xb0 kernel/exit.c:178 finish_task_switch+0x548/0x7a0 kernel/sched/core.c:3652 context_switch kernel/sched/core.c:3782 [inline] __schedule+0x89b/0x2130 kernel/sched/core.c:4528 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:4687 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:40 __mutex_lock_common kernel/locking/mutex.c:964 [inline] __mutex_lock+0xc00/0x10e0 kernel/locking/mutex.c:1103 futex_cleanup_begin kernel/futex.c:3677 [inline] futex_exit_release+0x26/0x220 kernel/futex.c:3729 exit_mm_release+0x16/0x30 kernel/fork.c:1322 exit_mm kernel/exit.c:438 [inline] do_exit+0x60d/0x29b0 kernel/exit.c:796 do_group_exit+0x125/0x310 kernel/exit.c:906 get_signal+0x42a/0x1f10 kernel/signal.c:2758 arch_do_signal+0x82/0x2390 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x100/0x1a0 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x38/0x260 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x449f79 Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 ab 03 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2b9fc53db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00000000006dfc28 RCX: 0000000000449f79 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006dfc28 RBP: 00000000006dfc20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dfc2c R13: 00007fff52ae4c5f R14: 00007f2b9fc549c0 R15: 00000000006dfc2c