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[Xen-devel] crash can't analyze memory dumpfile of Xen

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Subject: [Xen-devel] crash can't analyze memory dumpfile of Xen
From: Yuji Shimada <shimada-yxb@xxxxxxxxxxxxxxx>
Date: Wed, 03 Sep 2008 15:42:05 +0900
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I used the following tools to debug Xen.

  xen-3.3-unstable(changeset 17917)
  kexec-tools 2.0.0
  crash 4.0-6.3

Extraction of the memory dumpfile was completed normally. 
And I executed the following command to analyze memory dumpfile of Xen.

    # crash /boot/xen-syms-3.3-unstable dumpfile.core

The following errors occurred.

    crash: invalid kernel virtual address:0
    type:"note_buf_t or crash_note_t"
    WARNING: cannot fill note core.

    crash: cannot read elf note core.

I would like to ask some comments why these errors occurred.

I did the following steps:

 1.Boot Xen with the following Dom0 option. 
   And 2nd kernel is loaded by kexec.

 2.On Dom0 Linux, carry out crash dump.
     # echo c > /sys/sysrq-trigger
 3.On 2nd kernel, extract memory dumpfile.
     # makedumpfile -E -X /proc/vmcore dumpfile.core

 4.Reboot Xen and execute the following command.
   And the above errors occurred.
     # crash /boot/xen-syms-3.3-unstable dumpfile.core

I can read the same memory dumpfile by crash command with no error to
debug vmlinux.


Yuji Shimada

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