FYI, we noticed the following commit: https://github.com/0day-ci/linux Catalin-Marinas/mm-kmemleak-Avoid-using-__va-on-addresses-that-don-t-have-a-lowmem-mapping/20160816-232733 commit 122708b1b91eb3d253baf86a263ead0f1f5cac78 ("mm: kmemleak: Avoid using __va() on addresses that don't have a lowmem mapping") in testcase: boot on test machine: 1 threads qemu-system-i386 -enable-kvm with 320M memory caused below changes: +--------------------------------+------------+------------+ | | 304bec1b1d | 122708b1b9 | +--------------------------------+------------+------------+ | boot_successes | 3 | 0 | | boot_failures | 5 | 8 | | invoked_oom-killer:gfp_mask=0x | 1 | | | Mem-Info | 1 | | | BUG:kernel_test_crashed | 4 | | | PANIC:early_exception | 0 | 8 | | EIP_is_at__phys_addr | 0 | 8 | | BUG:kernel_hang_in_boot_stage | 0 | 2 | | BUG:kernel_boot_hang | 0 | 6 | +--------------------------------+------------+------------+ [ 0.000000] 319MB LOWMEM available. [ 0.000000] mapped low ram: 0 - 13fe0000 [ 0.000000] low ram: 0 - 13fe0000 [ 0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00PANIC: early exception 0x06 IP 60:c362d11e error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.8.0-rc1-mm1-00107-g122708b #286 [ 0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 0.000000] task: c3d46500 task.stack: c3d42000 [ 0.000000] EIP: 0060:[] EFLAGS: 00210087 CPU: 0 [ 0.000000] EIP is at __phys_addr+0x4d/0x55 [ 0.000000] EAX: 00000000 EBX: d3fe0000 ECX: 00000001 EDX: 00000000 [ 0.000000] ESI: 13fe0000 EDI: 00000000 EBP: c3d43ebc ESP: c3d43eb4 [ 0.000000] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 [ 0.000000] CR0: 80050033 CR2: 00000000 CR3: 03e25000 CR4: 000006b0 [ 0.000000] Stack: [ 0.000000] 00000000 1394a000 c3d43ee8 c3dc4f94 00000000 00000000 00000000 00000000 [ 0.000000] 00001000 00000000 c3d43fb0 00000000 c3d43f1c c3d43f14 c3dc51c0 00001000 [ 0.000000] 00000000 00000000 00000000 00000000 00000000 ffffffff 00000000 00000000 [ 0.000000] Call Trace: [ 0.000000] [] memblock_alloc_range_nid+0x8d/0x99 [ 0.000000] [] __memblock_alloc_base+0x1f/0x24 [ 0.000000] [] memblock_alloc_base+0x25/0x47 [ 0.000000] [] memblock_alloc+0x15/0x1a [ 0.000000] [] kvmclock_init+0x7e/0x200 [ 0.000000] [] setup_arch+0xac5/0xb61 [ 0.000000] [] start_kernel+0x88/0x36f [ 0.000000] [] i386_start_kernel+0x89/0x8d [ 0.000000] Code: ff ff 84 c0 74 02 0f 0b a1 d0 43 3c c4 85 c0 74 1c 89 f2 c1 ea 0c 39 c2 76 02 0f 0b 89 d8 e8 60 d2 ff ff 85 d2 75 04 39 f0 74 02 <0f> 0b 89 f0 5b 5e 5d c3 55 89 e5 53 89 c3 31 d2 3d ff ff ff bf Elapsed time: 440 BUG: kernel boot hang Linux version 4.8.0-rc1-mm1-00107-g122708b #286 Command line: ip=::::vm-lkp-wsx03-openwrt-i386-19::dhcp root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-19/boot-1-openwrt-i386.cgz-122708b1b91eb3d253baf86a263ead0f1f5cac78-20160817-3518-4j4d03-0.yaml ARCH=i386 kconfig=i386-randconfig-i0-201633 branch=linux-devel/devel-catchup-201608162349 commit=122708b1b91eb3d253baf86a263ead0f1f5cac78 BOOT_IMAGE=/pkg/linux/i386-randconfig-i0-201633/gcc-4.8/122708b1b91eb3d253baf86a263ead0f1f5cac78/vmlinuz-4.8.0-rc1-mm1-00107-g122708b max_uptime=600 RESULT_ROOT=/result/boot/1/vm-lkp-wsx03-openwrt-i386/openwrt-i386.cgz/i386-randconfig-i0-201633/gcc-4.8/122708b1b91eb3d253baf86a263ead0f1f5cac78/0 LKP_SERVER=inn 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 systemd.log_level=err ignore_loglevel earlyprintk=ttyS0,115200 console=ttyS0,115200 console=tty0 vga=normal rw drbd.minor_count=8 Thanks, Xiaolong