rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=07a/1/0x4000000000000002 softirq=11097/11097 fqs=42 (t=10501 jiffies g=6225 q=211) rcu: rcu_preempt kthread starved for 10418 jiffies! g6225 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28864 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 1 CPU: 1 PID: 8135 Comm: syz-executor.3 Not tainted 5.4.0-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:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 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:check_kcov_mode kernel/kcov.c:79 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:102 Code: 64 02 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 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 8d 7e 01 8b 89 84 RSP: 0018:ffffc90002386f40 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487326 RBX: ffffea00024e0240 RCX: ffff8880941a80c0 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00024e0240 RBP: ffffc90002386f68 R08: 000000000003a768 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a883a4a0 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff888097465628 free_thread_stack+0x168/0x590 kernel/fork.c:280 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 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:lock_release+0xc/0x780 kernel/locking/lockdep.c:4493 Code: 83 3d 0b 00 e8 07 00 0f 85 3d f7 ff ff e9 d2 f6 ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 <53> 48 83 ec 58 49 89 f5 49 89 ff 65 48 8b 04 25 28 00 00 00 48 89 RSP: 0018:ffffc900023871c0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff86eafc0e RBX: 0000000000000001 RCX: ffff8880941a80c0 RDX: 0000000000000000 RSI: ffffffff86eafc09 RDI: ffffffff890d4bc0 RBP: ffffc900023871e0 R08: dffffc0000000000 R09: ffffed1015da6fcd R10: ffffed1015da6fcd R11: 0000000000000000 R12: 0000000000000007 R13: 0000000000000000 R14: ffff8880965071a0 R15: ffff888096507000 rcu_lock_release+0x21/0x30 include/linux/rcupdate.h:213 rcu_read_unlock include/linux/rcupdate.h:671 [inline] in6_dev_get+0x1ed/0x220 include/net/addrconf.h:358 ndisc_netdev_event+0x11c/0x340 net/ipv6/ndisc.c:1787 notifier_call_chain kernel/notifier.c:95 [inline] __raw_notifier_call_chain kernel/notifier.c:396 [inline] raw_notifier_call_chain+0xec/0x190 kernel/notifier.c:403 __dev_notify_flags+0x24d/0x4d0 net/core/dev.c:1893 dev_change_flags+0xec/0x190 net/core/dev.c:8179 do_setlink+0xb2e/0x3960 net/core/rtnetlink.c:2589 __rtnl_newlink net/core/rtnetlink.c:3236 [inline] rtnl_newlink+0x14dd/0x1bd0 net/core/rtnetlink.c:3361 rtnetlink_rcv_msg+0x889/0xd40 net/core/rtnetlink.c:5422 netlink_rcv_skb+0x19e/0x3d0 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5440 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328 netlink_sendmsg+0xa21/0xd40 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: 0033:0x414373 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 fd 40 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:00007fffde0ea158 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000a72200 RCX: 0000000000414373 RDX: 0000000000000020 RSI: 0000000000a72250 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007fffde0ea160 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000a72250 R15: 0000000000000003