Crash加载ramdump报cpu_possible_mask异常问题

在使用Crash调试ramdump的时候发现一个错误，这里记录下。

[ 另外需要说明一点是,首先要确保vimlinx跟sysdump是同一次编译生成的,可以这样确认:

$ strings vmlinux |grep "Linux version"
Linux version 3.10.65-ge5e31c1 (android@ubuntu) (gcc version 4.8 (GCC) ) #7 SMP PREEMPT Fri May 19 15:50:19 CST 2017

$ strings sysdump |grep "Linux version"
Linux version 3.10.65-ge5e31c1 (android@ubuntu) (gcc version 4.8 (GCC) ) #7 SMP PREEMPT Fri May 19 15:50:19 CST 2017

---- 如此可见以上vmlinux跟sysdump是匹配的,否则无法继续调试.  ]

$crash vmlinux sysdump

crash 7.1.3

Copyright (C) 2002-2014 Red Hat, Inc.

Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation

Copyright (C) 1999-2006 Hewlett-Packard Co

Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited

Copyright (C) 2006, 2007 VA Linux Systems Japan K.K.

Copyright (C) 2005, 2011 NEC Corporation

Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc.

Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.

This program is free software, covered by the GNU General Public License,

and you are welcome to change it and/or distribute copies of it under

certain conditions. Enter "help copying" to see the conditions.

This program has absolutely no warranty. Enter "help warranty" for details.

GNU gdb (GDB) 7.6

Copyright (C) 2013 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law. Type "show copying"

and "show warranty" for details.

This GDB was configured as "--host=x86_64-unknown-linux-gnu --target=arm-elf-linux"...

crash: read error: kernel virtual address: c0629750 type: "cpu_possible_mask"

What happen ？

其实就是需要指定DDR起始地址就行了(各个平台定义不一样，可以查lk代码或者开机log看)：

#define PHYS_OFFSET_ADDR            0x80000000

$crash -m phys_base=0x80000000 vmlinux sysdump

crash 7.1.3

Copyright (C) 2002-2014 Red Hat, Inc.

Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation

Copyright (C) 1999-2006 Hewlett-Packard Co

Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited

Copyright (C) 2006, 2007 VA Linux Systems Japan K.K.

Copyright (C) 2005, 2011 NEC Corporation

Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc.

Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.

This program is free software, covered by the GNU General Public License,

and you are welcome to change it and/or distribute copies of it under

certain conditions. Enter "help copying" to see the conditions.

This program has absolutely no warranty. Enter "help warranty" for details.

NOTE: setting phys_base to: 0x80000000

GNU gdb (GDB) 7.6

Copyright (C) 2013 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law. Type "show copying"

and "show warranty" for details.

This GDB was configured as "--host=x86_64-unknown-linux-gnu --target=arm-elf-linux"...

please wait... (gathering task table data)

crash: invalid task address: e0776f40

crash: invalid task address: e0777480

crash: invalid task address: e0775a40

KERNEL: vmlinux

DUMPFILE: sysdump

CPUS: 4 [OFFLINE: 3]

DATE: Sun Jan 1 17:01:14 2017

UPTIME: 00:07:11

LOAD AVERAGE: 13.74, 10.87, 4.93

TASKS: 1136

NODENAME: localhost

RELEASE: 3.10.65-ge5e31c1

VERSION: #7 SMP PREEMPT Fri May 19 15:50:19 CST 2017

MACHINE: armv7l (unknown Mhz)

MEMORY: 1 GB

PANIC: "SysRq : Trigger a crash"

PID: 4591

COMMAND: "sh"

TASK: e8a24540 [THREAD_INFO: e8d7e000]

CPU: 2

STATE: TASK_RUNNING (SYSRQ)

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