jstack - well-known file is not secure
I am running tomcat 5.5 on x86_64 CentOS 5.7 using 32-bit Oracle Java 1.6.0.
JVM process used by tomcat has 6421 pid. Tomcat is working fine.
When run jstack it fails with:
[root@mybox ~]# jstack 6421
6421: well-known file is not secure
To get any reasonable output, I need to use force option:
[root@mybox ~]# jstack -F 6421
Attaching to process ID 6421, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 17.0-b16
Deadlock Detection:
No deadlocks found.
(...)
The questions are:
- what does the error message "well-known file is not secure" mean?
- what is the "well-known" file?
- why/when does the
jstackcommand not work without a force option?
Thanks in advance.
Answer
This is probably due to the file in /tmp used to communicate with the process having different permissions than the one the jstack gets. The file in question is /tmp/hsperfdata_$USER/$PID.
Don't know why it works with -F as the man page just says "Force a stack dump when 'jstack [-l] pid' does not respond."