[arch-general] GDB does not work, sometimes

[jb]

Rodrigo Rivas <rodrigorivascosta <at> gmail.com> writes:

> 
> Hi!
> 
> I'm having a very weird problem with gdb. I hadn't used the debugger for
> some time, so I'm not sure for how long it has been broken...
> The problem is that the debugged program does not stop in any breakpoing,
> exception, signal... nothing. Just as if it weren't being debugged.
> ...

No problem here. 
gdb 7.6.1-1
$ cat /proc/sys/kernel/yama/ptrace_scope 
1
$

Perhaps you should start with some basic steps.
Are you using any repos beyond the 3 basic ones (core, extra, community) ?

Re-install gdb the "hard" way:
pacman -Suy
pacman -R gdb
pacman -S gdb
find /etc -iname "*.pac*"

Verify dependencies:
pacman -Qi gdb

Verify:
$ ls -al /usr/bin/gdb
-rwxr-xr-x 1 root root 4634932 Aug 31 06:13 /usr/bin/gdb
$ ldd /usr/bin/gdb
	linux-gate.so.1 (0xb77b0000)
	libreadline.so.6 => /usr/lib/libreadline.so.6 (0xb775b000)
	libdl.so.2 => /usr/lib/libdl.so.2 (0xb7756000)
	libncursesw.so.5 => /usr/lib/libncursesw.so.5 (0xb76f7000)
	libz.so.1 => /usr/lib/libz.so.1 (0xb76e0000)
	libm.so.6 => /usr/lib/libm.so.6 (0xb769a000)
	libpthread.so.0 => /usr/lib/libpthread.so.0 (0xb767d000)
	libpython2.7.so.1.0 => /usr/lib/libpython2.7.so.1.0 (0xb74e5000)
	libexpat.so.1 => /usr/lib/libexpat.so.1 (0xb74bc000)
	liblzma.so.5 => /usr/lib/liblzma.so.5 (0xb7495000)
	libc.so.6 => /usr/lib/libc.so.6 (0xb72e5000)
	/lib/ld-linux.so.2 (0xb77b1000)
	libutil.so.1 => /usr/lib/libutil.so.1 (0xb72e0000)
$

Verify:
$ cat /etc/gdb/gdbinit
$ mv .gdbinit .gdbinit-save

You can try debugging gdb itself first:
$ gdb gdb
or
$ strace gdb

jb