How do I analyze and debug core files on AIX.

Sometimes, applications stop working and crash for any reason. A core file appears in scene.

First, we’re going  to set a PATH for all cores files on the system  using syscorepath command.

In order to do this, We’re going to:

1- Create and mount a new filesystem /corefiles

1.1- Create the new filesytem:

# crfs -v jfs2 -g volgrp2 -m /home/pipe -A yes -a size=1G
File system created successfully.
1048340 kilobytes total disk space.
New File System size is 2097152

1.2- Mount the filesystem:

# mount /corefiles

2- Using syscorepath command, we’ll set a PATH where all these cores files will be dumped..

2.1- Set the directory for all cores files:

# syscorepath -p /corefiles

2.2- To check if the core’s PATH was correctly set, running:

# syscorepath -g /corefiles
# /corefiles

3- Analize the core file using dbx command.

Once you get all cores in /corefiles, we’re going to analyse them using dbx command. Follow these steps:

3.1- Get the cause of the core file by running check_core command. In the example ksh93 is the victim:

# /usr/lib/ras/check_core /corefiles/core |tail -1

3.2- Debugging with dbx (Provides an environment to debug and run programs) command:

# dbx /usr/bin/ksh93 /corefiles/core
Type 'help' for help.
[using memory image in /corefiles/core]
reading symbolic information ...warning: no source compiled with -g

Segmentation fault in strlen at 0xd0105880
0xd0105880 (strlen)    89030000         lbz   r8,0x0(r3)

3.3- Once your are in dbx shell, type ‘where’

(dbx) where
strlen() at 0xd0105880
varsub() at 0x100475fc
copyto(??, ??) at 0x100494c8
sh_mactrim(??, ??) at 0x1004a5a0
word_trim(??, ??) at 0x1000e340
sh_exec(??, ??) at 0x1000ff88
sh_exec(??, ??) at 0x1001043c
sh_exec(??, ??) at 0x1000ff50
sh_exec(??, ??) at 0x10010470
sh_exec(??, ??) at 0x1000fdcc
sh_exec(??, ??) at 0x1000fd94
sh_exec(??, ??) at 0x1000fe08
sh_exec(??, ??) at 0x1000fdb8
sh_exec(??, ??) at 0x1000fe08
sh_exec(??, ??) at 0x1000fdb8
sh_exec(??, ??) at 0x100106d8
sh_exec(??, ??) at 0x1000fdb8
sh_exec(??, ??) at 0x1000fe08
sh_exec(??, ??) at 0x1000fd94
b_dot_cmd(??, ??, ??) at 0x10066e20
sh_funct(??, ??, ??, ??, ??) at 0x1000e500
sh_exec(??, ??) at 0x1000ee88
sh_exec(??, ??) at 0x1000fd94
sh_exec(??, ??) at 0x10010370
sh_exec(??, ??) at 0x1000fdb8
sh_exec(??, ??) at 0x1000fe98
exfile(??, ??) at 0x10000ed8
sh_main(??, ??, ??) at 0x100015dc
pmain.main(??, ??) at 0x10000370

Or you can use others dbx’s commands. Please see man dbx.

(dbx) thread
(dbx) map
(dbx) func
(dbx) dump
(dbx) quit

Just thanks if the post was helpful 🙂


About igalvarez

More than 20 years experiences on IT industry. 20+ years in Unix experience : IBM-AIX, HMC/SDMC/IVM, SVC, Protectier, PureFlex Systems, VIOservers, IBM Bladecenters, IBM System Power, RedHat Linux, SuSE Linux, Debian/Ubuntu Linux. Solaris, SCO Unix, Tru64 Unix, Linux Virtualization: XEN, KVM, databases sb2, oracle, postgreSQL, Find more information here:
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