README

pstack64 - pstack(1) analogue working with x84_64 binaries (pstack 64-bit / pstack amd64)
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Copyright (C) 2012 Jan Kisel - jdkrot@gmail.com

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

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    This actually a demonstation of how to take a backtrace of process and 
do it's pretty-printing. I think it's ok to use it for studying, but maybe 
it's not suitable for real case since it uses Perl and binutils instead of
doing this things correctly with libelf & libdwarf.

Benefits:
    o It's easy to read :-)
    o It shows symbols much faster than `gdb -batch` since it 
      performs a lazy lookup.
    o Works well with executables and shared objects. Falling back to dynamic 
      symbols lookup if none of them found in (debug) table.

Drawbacks:
    o It's strongly depends on GNU binutils and therefore it's Linux-only
    o It doesn't support threads (even if you pick up right LWP)


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Usage: ./pstack64 [-m N] [-Dv] pid [...]
   -v: be verbose (print debug information)
   -m N: unwind no more than N frames
   -D: do not demangle symbols

WARNING:
    If you see "Permission denied" message, then you need to turn off
ptrace(2)-protection: 
    $ sudo sysctl -w kernel.yama.ptrace_scope=0
    
    or simply run pstack64 using `sudo`. It's also necessary to trace processes
which doesn't belongs to you.