rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=83e/1/0x4000000000000000 softirq=26910/26910 fqs=0 (t=10500 jiffies g=9377 q=621) rcu: rcu_preempt kthread starved for 10500 jiffies! g9377 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:14336 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x404/0x8a0 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 schedule_timeout+0x1af/0x2d0 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0x707/0xc60 kernel/rcu/tree.c:2058 kthread+0x148/0x170 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 0 CPU: 0 PID: 15931 Comm: syz-executor.5 Not tainted 5.9.0-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+0xa3/0xcc lib/dump_stack.c:118 nmi_cpu_backtrace.cold.8+0x3e/0x58 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xd5/0xec lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0xa2/0xce 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.94+0x61/0x52d kernel/rcu/tree.c:2519 update_process_times+0x1f/0x60 kernel/time/timer.c:1710 tick_sched_handle.isra.24+0x1a/0x50 kernel/time/tick-sched.c:176 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1e1/0x510 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x8e/0x2b0 arch/x86/kernel/apic/apic.c:1097 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] sysvec_apic_timer_interrupt+0xc1/0xe0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:lock_release+0x20/0x2e0 kernel/locking/lockdep.c:5014 Code: fe ff ff e8 92 34 e0 01 66 90 41 56 41 55 41 54 49 89 f4 55 48 89 fd 53 48 83 ec 18 65 48 8b 04 25 28 00 00 00 48 89 44 24 10 <31> c0 0f 1f 44 00 00 65 8b 05 12 b7 dd 7e 83 f8 3f 0f 87 54 02 00 RSP: 0018:ffffc900025a7698 EFLAGS: 00000292 RAX: 2f1c074c3f2a1f00 RBX: ffffc900025a7890 RCX: 00000000fabdc8ef RDX: ffffc900025a7878 RSI: ffffffff82f19011 RDI: ffffc900025a78a8 RBP: ffffc900025a78a8 R08: 0000000000000000 R09: 0000000000000001 R10: ffff88810f9dc080 R11: c4fb2fd2b1771984 R12: ffffffff82f19011 R13: ffff8881216eed48 R14: ffffc900025a7878 R15: ffffc900025a7890 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x12/0x30 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:399 [inline] tipc_skb_peek_port net/tipc/msg.h:1251 [inline] tipc_sk_rcv+0xc1/0xa30 net/tipc/socket.c:2458 tipc_node_xmit+0x11d/0x3d0 net/tipc/node.c:1655 tipc_node_xmit_skb+0x34/0x50 net/tipc/node.c:1715 tipc_sk_rcv+0x7ed/0xa30 net/tipc/socket.c:2489 tipc_node_xmit+0x11d/0x3d0 net/tipc/node.c:1655 tipc_sk_push_backlog+0xa0/0x150 net/tipc/socket.c:1302 tipc_sk_filter_connect net/tipc/socket.c:2224 [inline] tipc_sk_filter_rcv+0x3ab/0xff0 net/tipc/socket.c:2333 tipc_sk_enqueue net/tipc/socket.c:2413 [inline] tipc_sk_rcv+0x506/0xa30 net/tipc/socket.c:2464 tipc_node_xmit+0x11d/0x3d0 net/tipc/node.c:1655 tipc_node_xmit_skb net/tipc/node.c:1715 [inline] tipc_node_distr_xmit+0x5a/0xe0 net/tipc/node.c:1730 tipc_sk_backlog_rcv+0x53/0x80 net/tipc/socket.c:2381 sk_backlog_rcv include/net/sock.h:1011 [inline] __release_sock+0x68/0x100 net/core/sock.c:2542 release_sock+0x26/0xa0 net/core/sock.c:3065 tipc_release+0x3d5/0x890 net/tipc/socket.c:638 __sock_release+0x32/0xa0 net/socket.c:596 sock_close+0xf/0x20 net/socket.c:1277 __fput+0xaa/0x250 fs/file_table.c:281 task_work_run+0x68/0xb0 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:163 [inline] exit_to_user_mode_prepare+0x219/0x220 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cba9 Code: 8d b6 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 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fad3dabec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 RAX: 0000000000000004 RBX: 00000000004dc020 RCX: 000000000045cba9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007 R13: 00000000000000a4 R14: 00000000004c3748 R15: 00007fad3dabf6d4