kdump of ubuntu12.04 cannot create kdump file, thanks!

[Caizhifeng]

hi,
         In order to test the ubuntu 12.04' kdump function, I do this follow operation step by step:
a)  sudo apt-get install linux-crashdump
b)  patch up : https://launchpadlibrarian.net/111207316/no-vmcoreinfo.patch
c)  open an ssh connection
c)  exec command "echo c > /proc/sysrq-trigger"

after these steps, the system do rebooted, but an error occur and hang on like this:
Begin: Running /script/init-bottom ... kdump: Missing /boot/vmcoreinfo-3.2.0-23-generic ..

BusyBox v1.18.5 (Ubuntu 1:1.18.5-1ubuntu4) build-in shell (ash)
Enter 'help' for a list of build-in commands.

(initramfs)


and no crash file created.

I search "vmcore" substring in " /usr/share/initramfs-tools/scripts/ " with no result, how to solve this problem?
Any information will be very much appreciated, Thanks for all.


log info:
root at ubuntu-0:~# uname -a
Linux ubuntu-0 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
root at ubuntu-0:~# service kdump  start
* Loading crashkernel; kexec -p "/boot/vmlinuz-3.2.0-23-generic" --initrd="/boot/initrd.img-3.2.0-23-generic" --append=" BOOT_IMAGE=/boot/vmlinuz-3.2.0-23-generic root=UUID=38e89080-5301-4b1d-93cd-30b70b5a4788 ro kdump_needed"...                                                                                    setup_linux_vesafb: 800x600x24 @ fc000000 +160000
                                                                                                                                                      [ OK ]
root at ubuntu-0:~# ls -lt /boot
total 22792
drwxr-xr-x 3 root root    12288 Jun 17 03:47 grub
-rw-r--r-- 1 root root 14171735 Jun 17 02:39 initrd.img-3.2.0-23-generic
-rw-r--r-- 1 root root   140279 Apr 10  2012 config-3.2.0-23-generic
-rw------- 1 root root  4965840 Apr 10  2012 vmlinuz-3.2.0-23-generic
....
root at ubuntu-0:~#


-------------------------------------------------------------------------------------------------------------------------------------
????????????????????????????????????????
????????????????????????????????????????
????????????????????????????????????????
???
This e-mail and its attachments contain confidential information from H3C, which is
intended only for the person or entity whose address is listed above. Any use of the
information contained herein in any way (including, but not limited to, total or partial
disclosure, reproduction, or dissemination) by persons other than the intended
recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender
by phone or email immediately and delete it!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-devel-discuss/attachments/20140620/3ce4528e/attachment.html>