I encountered a problem with my company's server application. I cannot kill that because I think that I won't be able to reproduce this error next time. So I want to know how can I get maximum information about the cause of this program freeze including but not limited to the function or routine inside of it.
How to know which procedure is executing right now?
You can debug the process with gdb --pid=PID and backtrace will give you stack trace to find out the function.
--pid=PID Attach to running process PID.
The example for the sleep
$ sleep 1000 &
[2] 13221
$ gdb --pid=13221
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Attaching to process 13221
Reading symbols from /usr/bin/sleep...Reading symbols from /usr/bin/sleep...(no debugging symbols found)...done.
(no debugging symbols found)...done.
Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
0x0000003122abc970 in __nanosleep_nocancel () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install coreutils-8.21-21.fc20.x86_64
(gdb) backtrace
#0 0x0000003122abc970 in __nanosleep_nocancel () from /lib64/libc.so.6
#1 0x00000000004040cf in rpl_nanosleep ()
#2 0x0000000000403f30 in xnanosleep ()
#3 0x00000000004018ed in main ()
(gdb)