Re: [Crash-utility] [PATCH v2] arm64: fix kernel memory map handling for kaslr-enabled kernel

----- Original Message ----- Here's the output from the updated non-randomized live system: crash> sys KERNEL: /usr/lib/debug/lib/modules/4.6.0-1.fc25.aarch64/vmlinux DUMPFILE: /dev/crash CPUS: 8 DATE: Wed May 25 11:30:06 2016 UPTIME: 00:18:43 LOAD AVERAGE: 0.01, 0.14, 0.17 TASKS: 200 NODENAME: apm-mustang-ev3-36.khw.lab.eng.bos.redhat.com RELEASE: 4.6.0-1.fc25.aarch64 VERSION: #1 SMP Mon May 16 23:11:08 UTC 2016 MACHINE: aarch64 (unknown Mhz) MEMORY: 16 GB crash> log ... [ cut ] ... [ 0.000000] Virtual kernel memory layout: [ 0.000000] modules : 0xfffffc0000000000 - 0xfffffc0008000000 ( 128 MB) [ 0.000000] vmalloc : 0xfffffc0008000000 - 0xfffffdfedfff0000 ( 2043 GB) [ 0.000000] .text : 0xfffffc0008080000 - 0xfffffc0008890000 ( 8256 KB) .rodata : 0xfffffc0008890000 - 0xfffffc0008c10000 ( 3584 KB) .init : 0xfffffc0008c10000 - 0xfffffc0008d50000 ( 1280 KB) .data : 0xfffffc0008d50000 - 0xfffffc0008eaac00 ( 1387 KB) [ 0.000000] vmemmap : 0xfffffdfee0000000 - 0xfffffdffe0000000 ( 4 GB maximum) 0xfffffdfee0000000 - 0xfffffdfee1000000 ( 16 MB actual) [ 0.000000] fixed : 0xfffffdfffe7d0000 - 0xfffffdfffec00000 ( 4288 KB) [ 0.000000] PCI I/O : 0xfffffdfffee00000 - 0xfffffdffffe00000 ( 16 MB) [ 0.000000] memory : 0xfffffe0000000000 - 0xfffffe0400000000 ( 16384 MB) ... The starting addresses are OK, but still the vmemmap range looks suspect: crash> help -m ... [ cut ] ... VA_BITS: 42 userspace_top: 0000040000000000 page_offset: fffffe0000000000 vmalloc_start_addr: fffffc0008000000 vmalloc_end: fffffdff5ffeffff modules_vaddr: fffffc0000000000 modules_end: fffffc0007ffffff vmemmap_vaddr: fffffdff80000000 ??? vmemmap_end: fffffdffffffffff kimage_text: fffffc0008080000 kimage_end: fffffc0009070000 kimage_voffset: 0000000000000000 phys_offset: 4000000000 ... crash> kmem fffffdff80000000 kmem: WARNING: cannot make virtual-to-physical translation: fffffdff80000000 fffffdff80000000: kernel virtual address not found in mem map crash> The vmemmap address from the log reads OK: crash> kmem -p | head -10 PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffdfee0000000 4000000000 fffffe03dc99f430 1b 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee0000040 4000010000 fffffe03dc99f430 1c 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee0000080 4000020000 fffffe03dc99f430 1d 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee00000c0 4000030000 fffffe03dc99f430 1e 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee0000100 4000040000 fffffe03dc99f430 1f 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee0000140 4000050000 fffffe03dc99f430 20 2 40078 uptodate,dirty,lru,active,swapbacked fffffdfee0000180 4000060000 fffffe03dc99f430 21 2 4003c referenced,uptodate,dirty,lru,swapbacked fffffdfee00001c0 4000070000 fffffe03dc99f430 22 2 40078 uptodate,dirty,lru,active,swapbacked fffffdfee0000200 4000080000 0 0 1 400 reserved ... [ cut ] ... fffffdfee0fffd80 43fff60000 0 0 1 4000000000000400 reserved fffffdfee0fffdc0 43fff70000 0 0 1 4000000000000400 reserved fffffdfee0fffe00 43fff80000 0 0 1 4000000000000400 reserved fffffdfee0fffe40 43fff90000 0 0 1 4000000000000400 reserved fffffdfee0fffe80 43fffa0000 0 0 1 4000000000000400 reserved fffffdfee0fffec0 43fffb0000 0 0 1 4000000000000400 reserved fffffdfee0ffff00 43fffc0000 0 0 1 4000000000000400 reserved fffffdfee0ffff40 43fffd0000 0 0 1 4000000000000400 reserved fffffdfee0ffff80 43fffe0000 0 0 1 4000000000000400 reserved fffffdfee0ffffc0 43ffff0000 0 0 1 4000000000000400 reserved crash> And again, the page_offset is fffffe0000000000 with a kernel VA_BITS configuration of 42: kernel-4.6.0-aarch64.config:CONFIG_ARM64_VA_BITS_42=y kernel-4.6.0-aarch64.config:# CONFIG_ARM64_VA_BITS_48 is not set kernel-4.6.0-aarch64.config:CONFIG_ARM64_VA_BITS=42 Dave