FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git x86/vmap_stack commit 87194cac139aebecec89a68eff719ab44f0469a2 ("x86: Move thread_info into task_struct") on test machine: vm-vp-quantal-x86_64: 2 threads qemu-system-x86_64 -enable-kvm with 360M memory caused below changes: +------------------------------------------+------------+------------+ | | 01ac3242f3 | 87194cac13 | +------------------------------------------+------------+------------+ | boot_successes | 10 | 0 | | boot_failures | 2 | 34 | | BUG:kernel_test_oversize | 2 | | | BUG:unable_to_handle_kernel | 0 | 34 | | Oops:#[##] | 0 | 34 | | RIP:entry_SYSCALL_64_after_swapgs | 0 | 34 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 34 | +------------------------------------------+------------+------------+ [ 1.891698] Freeing unused kernel memory: 984K (ffff88000150a000 - ffff880001600000) [ 1.897808] Freeing unused kernel memory: 1660K (ffff880001861000 - ffff880001a00000) [ 1.897808] Freeing unused kernel memory: 1660K (ffff880001861000 - ffff880001a00000) [ 1.900225] BUG: unable to handle kernel [ 1.900225] BUG: unable to handle kernel paging requestpaging request at ffffffff03460040 at ffffffff03460040 [ 1.902293] IP: [ 1.902293] IP: [<ffffffff81506684>] entry_SYSCALL_64_after_swapgs+0x31/0x47 FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -kernel /pkg/linux/x86_64-randconfig-v0-06261108/gcc-6/87194cac139aebecec89a68eff719ab44f0469a2/vmlinuz-4.7.0-rc4-00258-g87194ca -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-vp-quantal-x86_64-2/bisect_boot-1-quantal-core-x86_64.cgz-x86_64-randconfig-v0-06261108-87194cac139aebecec89a68eff719ab44f0469a2-20160626-43628-vqpxp-0.yaml ARCH=x86_64 kconfig=x86_64-randconfig-v0-06261108 branch=linux-devel/devel-hourly-2016062608 commit=87194cac139aebecec89a68eff719ab44f0469a2 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-v0-06261108/gcc-6/87194cac139aebecec89a68eff719ab44f0469a2/vmlinuz-4.7.0-rc4-00258-g87194ca max_uptime=600 RESULT_ROOT=/result/boot/1/vm-vp-quantal-x86_64/quantal-core-x86_64.cgz/x86_64-randconfig-v0-06261108/gcc-6/87194cac139aebecec89a68eff719ab44f0469a2/0 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_64-2::dhcp drbd.minor_count=8' -initrd /fs/sdh1/initrd-vm-vp-quantal-x86_64-2 -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_64-2 -serial file:/dev/shm/kboot/serial-vm-vp-quantal-x86_64-2 -daemonize -display none -monitor null Thanks, Kernel Test Robot