rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=c26/1/0x4000000000000002 softirq=13407/13413 fqs=137 (t=10500 jiffies g=6893 q=542) rcu: rcu_preempt kthread starved for 10217 jiffies! g6893 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28824 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 8464 Comm: syz-executor.5 Not tainted 5.5.0-rc5-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+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:155 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x50 kernel/kcov.c:187 Code: ed 07 48 89 de e8 84 f4 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 38 5f 8b 7e f7 c2 00 01 1f 00 75 2c <8b> 91 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 RSP: 0018:ffffc900022c75f0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81489244 RBX: ffffea000250da00 RCX: ffff888097cee0c0 RDX: 0000000000000001 RSI: 00000000fffffffc RDI: ffffea000250da00 RBP: ffffc900022c7630 R08: 000000000003a728 R09: ffffed1010d18ef1 R10: ffffed1010d18ef1 R11: 0000000000000000 R12: ffff88809393e7a0 R13: dffffc0000000000 R14: 1ffff11012727cf4 R15: ffff8880868c7778 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 mutex_optimistic_spin+0x445/0x480 kernel/locking/mutex.c:707 __mutex_lock_common+0x2e7/0x2e10 kernel/locking/mutex.c:959 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x83c/0xd40 net/core/rtnetlink.c:5421 netlink_rcv_skb+0x19e/0x3d0 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5442 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328 netlink_sendmsg+0xa31/0xd50 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg net/socket.c:659 [inline] __sys_sendto+0x442/0x5e0 net/socket.c:1985 __do_sys_sendto net/socket.c:1997 [inline] __se_sys_sendto net/socket.c:1993 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:1993 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414c43 Code: ff 0f 83 b0 19 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 2d 38 66 00 00 75 17 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 81 19 00 00 c3 48 83 ec 08 e8 87 fa ff ff RSP: 002b:00007ffeeee5c8e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000a72200 RCX: 0000000000414c43 RDX: 000000000000002c RSI: 0000000000a72250 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffeeee5c8f0 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000a72250 R15: 0000000000000003