root@mds1:~# stat /core
  File: `/core'
  Size: 555253760 	Blocks: 674464     IO Block: 4096   regular file
Device: 801h/2049d	Inode: 664         Links: 1
Access: (0600/-rw-------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2010-06-03 13:05:22.126414913 +0200
Modify: 2010-06-03 12:58:16.187665088 +0200
Change: 2010-06-03 12:58:16.187665088 +0200
root@mds1:~#

root@mds1:~# gdb /usr/lib/debug/usr/bin/cmds /core
GNU gdb (GDB) 7.1-ubuntu
Copyright (C) 2010 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 "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/lib/debug/usr/bin/cmds...done.
[New Thread 9178]
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warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
Core was generated by `/usr/bin/cmds -i 1 -c /etc/ceph/ceph.conf'.
Program terminated with signal 11, Segmentation fault.
#0  0x00000000012418a0 in ?? ()
(gdb) bt
#0  0x00000000012418a0 in ?? ()
#1  0x0000000000510ba3 in MDSCacheObject::put (this=0xd3ca40, mdr=0x1f3bfa0) at mds/mdstypes.h:1209
#2  Mutation::drop_pins (this=0xd3ca40, mdr=0x1f3bfa0) at mds/MDCache.h:148
#3  MDCache::request_cleanup (this=0xd3ca40, mdr=0x1f3bfa0) at mds/MDCache.cc:6545
#4  0x0000000001f3bfa0 in ?? ()
#5  0x0000000000d30f90 in ?? ()
#6  0x0000000000d38ef0 in ?? ()
#7  0x0000000001f3bfa0 in ?? ()
#8  0x0000000000000000 in ?? ()
(gdb)