rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=28a/1/0x4000000000000000 softirq=139711/139711 fqs=0 (t=10501 jiffies g=283669 q=126) rcu: rcu_preempt kthread starved for 10502 jiffies! g283669 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: rcu_preempt R running task 29120 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x148/0x250 kernel/time/timer.c:1897 rcu_gp_fqs_loop kernel/rcu/tree.c:1874 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2044 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 NMI backtrace for cpu 0 CPU: 0 PID: 27575 Comm: syz-executor.0 Not tainted 5.8.0-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:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:320 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline] check_cpu_stall kernel/rcu/tree_stall.h:627 [inline] rcu_pending kernel/rcu/tree.c:3489 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccc kernel/rcu/tree.c:2504 update_process_times+0x25/0x60 kernel/time/timer.c:1726 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x108/0x290 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4f/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x8c/0xe0 kernel/locking/spinlock.c:191 Code: 48 c7 c0 80 e0 b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 37 48 83 3d 3b 16 cd 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 35 a8 67 f9 65 8b 05 5e 34 1a 78 RSP: 0018:ffffc90000007cb8 EFLAGS: 00000282 RAX: 1ffffffff1369c10 RBX: 0000000000000282 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000282 RBP: ffff88804e62ed08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88804e62ed08 R14: 1ffff92000000fa9 R15: dffffc0000000000 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] skb_dequeue+0x125/0x180 net/core/skbuff.c:3040 mrp_queue_xmit net/802/mrp.c:350 [inline] mrp_join_timer+0x97/0xc0 net/802/mrp.c:595 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers.part.0+0x54c/0xa20 kernel/time/timer.c:1773 __run_timers kernel/time/timer.c:1745 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1786 __do_softirq+0x34c/0xa60 kernel/softirq.c:292 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x111/0x170 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:387 [inline] __irq_exit_rcu kernel/softirq.c:417 [inline] irq_exit_rcu+0x229/0x270 kernel/softirq.c:429 sysvec_apic_timer_interrupt+0x54/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587 RIP: 0010:write_comp_data+0x2f/0x80 kernel/kcov.c:218 Code: 05 76 49 8e 7e 65 48 8b 34 25 00 ff 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 04 14 00 00 85 c0 74 4f 8b 86 e0 13 00 00 <83> f8 03 75 44 48 8b 86 e8 13 00 00 8b b6 e4 13 00 00 4c 8b 00 48 RSP: 0018:ffffc9000ce2f7e0 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffea0001b71540 RCX: ffffffff81ae6dc7 RDX: 0000000000000000 RSI: ffff8880132fa5c0 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffea0001b71547 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffea0001b71548 R14: 0000000000000000 R15: ffffea0001d70e48 PageCompound include/linux/page-flags.h:196 [inline] PageHuge+0x47/0x170 mm/hugetlb.c:1546 page_remove_file_rmap mm/rmap.c:1241 [inline] page_remove_rmap+0x9a0/0x1670 mm/rmap.c:1331 zap_pte_range mm/memory.c:1089 [inline] zap_pmd_range mm/memory.c:1193 [inline] zap_pud_range mm/memory.c:1222 [inline] zap_p4d_range mm/memory.c:1243 [inline] unmap_page_range+0xf3b/0x2940 mm/memory.c:1264 unmap_single_vma+0x198/0x300 mm/memory.c:1309 unmap_vmas+0x16f/0x2f0 mm/memory.c:1341 unmap_region+0x231/0x380 mm/mmap.c:2613 __do_munmap+0x65d/0x10d0 mm/mmap.c:2833 do_munmap mm/mmap.c:2844 [inline] mmap_region+0x257/0x1590 mm/mmap.c:1715 do_mmap+0xca8/0x1170 mm/mmap.c:1545 do_mmap_pgoff include/linux/mm.h:2596 [inline] vm_mmap_pgoff+0x197/0x200 mm/util.c:506 ksys_mmap_pgoff+0x455/0x5a0 mm/mmap.c:1595 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cba9 Code: Bad RIP value. RSP: 002b:00007f8e0e6c2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00000000004f7900 RCX: 000000000045cba9 RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 000000000078bf00 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000028011 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000770 R14: 00000000004ca623 R15: 00007f8e0e6c36d4