Java Troubleshooting Guide for HP-UX Systems

core.29757
$ ll core.29757
total 429296
-rw------- 1 test users 219781020 Aug 29 12:33 core
-rw-rw-rw- 1 test users 2191 Aug 29 12:33 hs_err_pid29757.log
3.2.1.1.5 Ensure Permissions Allow Core Files
Some Java processes run setuid; that is, a process where the effective uid or gid differs from the
real uid or gid. On HP-UX 11i v1 (11.11) and later versions a kernel security feature prevents
core file creation for these processes. Use the following command when you are logged in as the
root user to enable core dumps of setuid Java processes:
$ echo "dump_all/W 1" | adb -w /stand/vmunix /dev/kmem
This capability is turned on only for the current boot.
3.2.1.2 Generating a Core File
Analyzing the core file is essential for troubleshooting problems. Core files are automatically
generated for application aborts. For hung processes and performance issues, you need to generate
them using the gdb dumpcore command.
The gdb dumpcore command forces the generation of a core file without killing a running
process. This command causes a core file named core.<pid> to be created. The current process
state is not modified when this command is issued.
The following example shows a Java application running on an Integrity system:
$ echo "dumpcore\nq" > gdb_cmds
$ ps -u myuser | grep java
12290 pts/6 12:58 java
$ gdb --command=gdb_cmds -batch /opt/java1.4/bin/IA64N/java 12290
This generates a core file in the current directory with the name core.12290.
On HP-UX 11i v3 (11.31), another way to generate a core file is by using the gcore command.
The following example shows invocation of gcore to dump the core image of process 11050.
The core image is written to the core.11050 file by default:
$ gcore 11050
3.2.1.3 Verifying a Core File
After you have successfully collected your core file, you should verify that it is complete and
valid with the following two steps.
First, open the core file in gdb and check the error and warning messages. If the message
“<corefilename> is not a core dump: File format not recognized“ is displayed when you open
the file, your core file is invalid. The following example shows how to verify a core file produced
by a 32-bit application on a PA-RISC system. In this example, the core file is valid.
$ gdb /opt/java1.4/jre/lib/PA_RISC2.0/server/libjunwind.sl core
HP gdb 5.5.7 for PA-RISC 1.1 or 2.0 (narrow), HP-UX 11.00 and target hppa1.1-hp-hpux11.00.
Copyright 1986 - 2001 Free Software Foundation, Inc.
Hewlett-Packard Wildebeest 5.5.7 (based on GDB) is covered by the GNU General Public License.
Type "show copying" to see the conditions to change it and/or distribute copies.
Type "show warranty" for warranty/support.
..
Core was generated by `java'. Program terminated with signal 6, Aborted.
#0 0xc0214db0 in kill+0x10 () from ./libc.2
Second, check to make sure that the core file was not truncated by issuing the “what core”
command. If you do not see the dld.sl version at the bottom of the what output, then the core
file is truncated and is not usable. In the following example, the dld.sl version exists at the
bottom of the what output, so you know the core file is not truncated:
$ what core
core:
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