FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/random.git dev commit 229b0d4ca2d7afbad4635e00d10c02aa7cc20d45 ("random: replace non-blocking pool with a Chacha20-based CRNG") on test machine: vm-lkp-wsx03-openwrt-i386: 1 threads qemu-system-i386 -enable-kvm with 192M memory caused below changes: +----------------+----------+------------+ | | v4.7-rc1 | 229b0d4ca2 | +----------------+----------+------------+ | boot_successes | 28 | 2 | +----------------+----------+------------+ [ 1505.386362] Writes: Total: 2 Max/Min: 0/0 Fail: 0 Elapsed time: 1530 BUG: kernel test hang qemu-system-i386 -enable-kvm -kernel /pkg/linux/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/vmlinuz-4.7.0-rc1-00001-g229b0d4 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-19/bisect_boot-1-openwrt-i386.cgz-i386-randconfig-n0-201624-229b0d4ca2d7afbad4635e00d10c02aa7cc20d45-20160613-1532-1d2nvlr-0.yaml~ ARCH=i386 kconfig=i386-randconfig-n0-201624 branch=linux-devel/devel-spot-201606122112 commit=229b0d4ca2d7afbad4635e00d10c02aa7cc20d45 BOOT_IMAGE=/pkg/linux/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/vmlinuz-4.7.0-rc1-00001-g229b0d4 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-lkp-wsx03-openwrt-i386/openwrt-i386.cgz/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/0 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-lkp-wsx03-openwrt-i386-19::dhcp drbd.minor_count=8' -initrd /fs/sdc1/initrd-vm-lkp-wsx03-openwrt-i386-19 -m 192 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdc1/disk0-vm-lkp-wsx03-openwrt-i386-19,media=disk,if=virtio -drive file=/fs/sdc1/disk1-vm-lkp-wsx03-openwrt-i386-19,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-lkp-wsx03-openwrt-i386-19 -serial file:/dev/shm/kboot/serial-vm-lkp-wsx03-openwrt-i386-19 -daemonize -display none -monitor null FYI, raw QEMU command line is: qemu-system-i386 -enable-kvm -kernel /pkg/linux/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/vmlinuz-4.7.0-rc1-00001-g229b0d4 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-19/bisect_boot-1-openwrt-i386.cgz-i386-randconfig-n0-201624-229b0d4ca2d7afbad4635e00d10c02aa7cc20d45-20160613-1532-1d2nvlr-0.yaml~ ARCH=i386 kconfig=i386-randconfig-n0-201624 branch=linux-devel/devel-spot-201606122112 commit=229b0d4ca2d7afbad4635e00d10c02aa7cc20d45 BOOT_IMAGE=/pkg/linux/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/vmlinuz-4.7.0-rc1-00001-g229b0d4 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-lkp-wsx03-openwrt-i386/openwrt-i386.cgz/i386-randconfig-n0-201624/gcc-6/229b0d4ca2d7afbad4635e00d10c02aa7cc20d45/0 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-lkp-wsx03-openwrt-i386-19::dhcp drbd.minor_count=8' -initrd /fs/sdc1/initrd-vm-lkp-wsx03-openwrt-i386-19 -m 192 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdc1/disk0-vm-lkp-wsx03-openwrt-i386-19,media=disk,if=virtio -drive file=/fs/sdc1/disk1-vm-lkp-wsx03-openwrt-i386-19,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-lkp-wsx03-openwrt-i386-19 -serial file:/dev/shm/kboot/serial-vm-lkp-wsx03-openwrt-i386-19 -daemonize -display none -monitor null Thanks, Kernel Test Robot