rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=3f2/1/0x4000000000000000 softirq=86422/86422 fqs=27 (t=10500 jiffies g=164033 q=307) rcu: rcu_preempt kthread starved for 10238 jiffies! g164033 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 29160 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 1 CPU: 1 PID: 22534 Comm: syz-executor.0 Not tainted 5.8.0-next-20200814-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:165 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 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:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650 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+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x4b/0x80 kernel/locking/spinlock.c:199 Code: c0 18 35 b6 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d b6 8d bf 01 00 74 25 fb 66 0f 1f 44 00 00 01 00 00 00 e8 bb 0b 59 f9 65 8b 05 04 57 0b 78 85 c0 74 02 5d RSP: 0018:ffffc90000da8e00 EFLAGS: 00000286 RAX: 1ffffffff136c6a3 RBX: ffffffff86576490 RCX: 1ffffffff15760b9 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff87f6a73f RBP: ffff8880ae7255c0 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000da8e90 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880ae7255c0 expire_timers kernel/time/timer.c:1457 [inline] __run_timers.part.0+0x66c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x2de/0xa24 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __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+0x9d/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+0x1f3/0x230 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:lock_is_held_type+0x17/0xf0 kernel/locking/lockdep.c:5035 Code: 31 51 f9 0f 0b 8b 04 24 e9 f0 fe ff ff 66 0f 1f 44 00 00 41 57 41 56 41 55 41 54 55 53 48 83 ec 08 65 48 8b 2c 25 c0 fe 01 00 <8b> 95 ec 08 00 00 89 74 24 04 85 d2 0f 85 a9 00 00 00 4c 8d ad f0 RSP: 0018:ffffc900171afce8 EFLAGS: 00000296 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 00000000ffffffff RDI: ffffffff89c66b80 RBP: ffff888049e34540 R08: 0000000000000001 R09: ffff888049e34e28 R10: fffffbfff1576841 R11: 0000000000000000 R12: 0000000000000ba8 R13: 0000000000000cc0 R14: ffff8880a97b7a00 R15: dffffc0000000000 lock_is_held include/linux/lockdep.h:267 [inline] ___might_sleep+0x268/0x2f0 kernel/sched/core.c:7272 cache_alloc_debugcheck_before mm/slab.c:2984 [inline] cache_alloc_debugcheck_before mm/slab.c:2981 [inline] slab_alloc mm/slab.c:3302 [inline] kmem_cache_alloc+0x2fd/0x3a0 mm/slab.c:3482 sock_alloc_inode+0x18/0x1c0 net/socket.c:253 alloc_inode+0x61/0x230 fs/inode.c:232 new_inode_pseudo+0x14/0xe0 fs/inode.c:928 sock_alloc+0x3c/0x260 net/socket.c:573 __sock_create+0xb9/0x740 net/socket.c:1391 sock_create net/socket.c:1478 [inline] __sys_socket+0xef/0x200 net/socket.c:1520 __do_sys_socket net/socket.c:1529 [inline] __se_sys_socket net/socket.c:1527 [inline] __x64_sys_socket+0x6f/0xb0 net/socket.c:1527 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d239 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5882e57c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000031b80 RCX: 000000000045d239 RDX: 0000000000000000 RSI: 0000000000000803 RDI: 0000000000000010 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd9d505a2f R14: 00007f5882e589c0 R15: 000000000118cf4c