pstack's man page says it's a 32-bit only program, so independent of the Ubuntu version:
Originally Posted by ibjsb4
The weird thing is that I installed and run it on my 64-bit Ubuntu (without any useful output, I must say). So, why make a program installable on a 64-bit system if the man page says it does not work? Or is the man page out of date?
pstack currently works only on Linux, only on an x86 machine running 32 bit ELF binaries (64 bit not supported).
sander@flappie:~$ sudo pstack 2623
2623: chromium-browser --type=plugin --plugin-path=/usr/lib/flashplugin-installer/libflashplayer.so --lang=en-US --channel=2339.7....
(No symbols found)
crawl: Input/output error
Error tracing through process 2623
sander@flappie:~$ uname -a
Linux flappie 3.8.0-30-generic #44-Ubuntu SMP Thu Aug 22 20:52:24 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux