Why can't gdb attach to server application summoned with inetd?
https://stackoverflow.com/questions/1586812
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I have a server application that can be summoned for the client using inetd. However, if I try to attach to the server process that was launched with inetd, I get the following response: ptrace: Operation not permitted.
gdb --annotate=3 /my/app/here <processId>
Current directory is /usr/local/bin/
GNU gdb 6.8
Copyright (C) 2008 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 "i686-pc-linux-gnu"...
Reading symbols from /usr/local/bin/flumed...done.
Using host libthread_db library "/lib/tls/libthread_db.so.1".
Attaching to program: /my/app/here, process <processId>
ptrace: Operation not permitted.
/usr/local/bin/<processId>: No such file or directory.
(gdb)
Solution 2
Apparently, things get funky with inetd where the userid is not root. You end up with a process with weird permissions. For example, you are unable to read /proc/self/exe even though the permissions are 777. I suspect this issue is more of the same. Even though I'm the userid of the process, I don't have permissions. Using root for gdb is a work around.
OTHER TIPS
Solution for me was this:
echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
Further to what tgoodhart said, other ptrace users like /usr/bin/strace will also block gdb.
I have also seen this problem occur when multiple instances of gdb are running at the same time, usually because I failed to close gdb correctly. Closing these leaked instances fixed the problem.
Pls run the following command to solve ur problem:
sudo chmod +s /usr/bin/gdb
