(entering IDLE with pending SCHED/HRTIMER/TASK softirqs... should run pending softirq before entering IDLE i suppose?) What are the consequences of 
entering HLT with pending softirqs?


1) Kernel: kernel-rt-3.10.0-644.rt56.560.el7.x86_64
(had started a KVM guest, then DHCP activity, chrony...).

Apr 19 16:24:21 localhost avahi-daemon[909]: Registering new address record for fe80::405d:8dff:fe33:9eb4 on tap0.*.
Apr 19 16:24:21 localhost kernel: virbr0: port 2(tap0) entered learning state
Apr 19 16:24:23 localhost NetworkManager[961]: <info>  [1492629863.6244] device (virbr0): link connected
Apr 19 16:24:23 localhost kernel: virbr0: port 2(tap0) entered forwarding state
Apr 19 16:24:23 localhost kernel: virbr0: topology change detected, propagating
Apr 19 16:24:23 localhost kernel: IPv6: ADDRCONF(NETDEV_CHANGE): virbr0: link becomes ready
Apr 19 16:24:26 localhost kernel: kvm [3667]: vcpu0 unhandled rdmsr: 0x606
Apr 19 16:24:32 localhost kernel: kvm [3667]: vcpu0 unhandled rdmsr: 0x611
Apr 19 16:24:32 localhost kernel: kvm [3667]: vcpu0 unhandled rdmsr: 0x639
Apr 19 16:24:32 localhost kernel: kvm [3667]: vcpu0 unhandled rdmsr: 0x641
Apr 19 16:24:32 localhost kernel: kvm [3667]: vcpu0 unhandled rdmsr: 0x619
Apr 19 16:25:20 localhost dnsmasq-dhcp[2280]: DHCPDISCOVER(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:20 localhost dnsmasq-dhcp[2280]: DHCPOFFER(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:20 localhost dnsmasq-dhcp[2280]: DHCPREQUEST(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:20 localhost dnsmasq-dhcp[2280]: DHCPACK(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:22 localhost dnsmasq-dhcp[2280]: DHCPDISCOVER(virbr0) 52:54:00:d8:75:ac
Apr 19 16:25:22 localhost dnsmasq-dhcp[2280]: DHCPOFFER(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:22 localhost dnsmasq-dhcp[2280]: DHCPREQUEST(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:25:22 localhost dnsmasq-dhcp[2280]: DHCPACK(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:28:17 localhost systemd: Starting Cleanup of Temporary Directories...
Apr 19 16:28:30 localhost systemd: Started Cleanup of Temporary Directories.
Apr 19 16:30:02 localhost systemd: Started Session 6 of user root.
Apr 19 16:30:02 localhost systemd: Starting Session 6 of user root.
Apr 19 16:35:14 localhost systemd-logind: New session 7 of user root.
Apr 19 16:35:14 localhost systemd: Started Session 7 of user root.
Apr 19 16:35:14 localhost systemd: Starting Session 7 of user root.
Apr 19 16:35:29 localhost systemd-logind: Removed session 7.
Apr 19 16:38:14 localhost chronyd[924]: Can't synchronise: no selectable sources
Apr 19 16:40:02 localhost systemd: Started Session 8 of user root.
Apr 19 16:40:02 localhost systemd: Starting Session 8 of user root.
Apr 19 16:48:30 localhost dnsmasq-dhcp[2280]: DHCPREQUEST(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:48:30 localhost dnsmasq-dhcp[2280]: DHCPACK(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:50:01 localhost systemd: Started Session 9 of user root.
Apr 19 16:50:01 localhost systemd: Starting Session 9 of user root.
Apr 19 16:52:30 localhost dnsmasq-dhcp[2280]: DHCPREQUEST(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 16:52:30 localhost dnsmasq-dhcp[2280]: DHCPACK(virbr0) 192.168.122.65 52:54:00:d8:75:ac
Apr 19 17:00:01 localhost systemd: Started Session 10 of user root.
Apr 19 17:00:01 localhost systemd: Starting Session 10 of user root.
Apr 19 17:01:01 localhost systemd: Started Session 11 of user root.
Apr 19 17:01:01 localhost systemd: Starting Session 11 of user root.
Apr 19 17:09:07 localhost systemd-logind: New session 12 of user root.
Apr 19 17:09:07 localhost systemd: Started Session 12 of user root.
Apr 19 17:09:07 localhost systemd: Starting Session 12 of user root.
Apr 19 17:09:28 localhost dbus-daemon: dbus[957]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 19 17:09:28 localhost dbus[957]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 19 17:09:28 localhost dbus-daemon: dbus[957]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 19 17:09:28 localhost dbus[957]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 19 17:10:01 localhost systemd: Started Session 13 of user root.
Apr 19 17:10:01 localhost systemd: Starting Session 13 of user root.
Apr 19 17:10:35 localhost chronyd[924]: Selected source 200.160.7.193
Apr 19 17:14:51 localhost systemd-logind: Removed session 2.
Apr 19 17:15:01 localhost avahi-daemon[909]: Withdrawing address record for fe80::405d:8dff:fe33:9eb4 on tap0.
Apr 19 17:15:01 localhost kernel: CPU1: NOHZ: local_softirq_pending: TASKLET
Apr 19 17:15:01 localhost kernel: CPU1: NOHZ: local_softirq_pending: TASKLET
Apr 19 17:15:01 localhost kernel: virbr0: port 2(tap0) entered disabled state

2) Kernel: 3.10.0-631.rt56.546.el7.x86_64


Description of https://bugzilla.redhat.com/show_bug.cgi?id=1438120

So at present there does not seem to be a synthetic reproducer.