FYI, we noticed the following commit: https://github.com/0day-ci/linux Rhyland-Klein/power_supply-power_supply_read_temp-only-if-use_cnt-0/20160610-053415 commit 1235baeac82d3113a7334f55a3fef160c5a4b983 ("power_supply: power_supply_read_temp only if use_cnt > 0") on test machine: vm-vp-quantal-x86_64: 2 threads qemu-system-x86_64 -enable-kvm with 360M memory caused below changes: [ 5.908066] __power_supply_register: Expected proper parent device for 'test_ac' [ 5.911184] __power_supply_register: Expected proper parent device for 'test_battery' [ 5.915462] thermal thermal_zone0: failed to read out thermal zone (-19) [ 5.917370] __power_supply_register: Expected proper parent device for 'test_usb' FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -kernel /pkg/linux/x86_64-randconfig-s3-06100451/gcc-6/1235baeac82d3113a7334f55a3fef160c5a4b983/vmlinuz-4.6.0-rc2-00006-g1235bae -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-vp-quantal-x86_64-17/rand_boot-1-quantal-core-x86_64.cgz-x86_64-randconfig-s3-06100451-1235baeac82d3113a7334f55a3fef160c5a4b983-20160610-77925-1xs3hv7-0.yaml~ ARCH=x86_64 kconfig=x86_64-randconfig-s3-06100451 branch=linux-devel/devel-spot-201606100535 commit=1235baeac82d3113a7334f55a3fef160c5a4b983 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s3-06100451/gcc-6/1235baeac82d3113a7334f55a3fef160c5a4b983/vmlinuz-4.6.0-rc2-00006-g1235bae max_uptime=600 RESULT_ROOT=/result/boot/1/vm-vp-quantal-x86_64/quantal-core-x86_64.cgz/x86_64-randconfig-s3-06100451/gcc-6/1235baeac82d3113a7334f55a3fef160c5a4b983/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-vp-quantal-x86_64-17::dhcp drbd.minor_count=8' -initrd /fs/sdb1/initrd-vm-vp-quantal-x86_64-17 -m 360 -smp 2 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -pidfile /dev/shm/kboot/pid-vm-vp-quantal-x86_64-17 -serial file:/dev/shm/kboot/serial-vm-vp-quantal-x86_64-17 -daemonize -display none -monitor null Thanks, Xiaolong