Missing thread support..

Missing thread support..

[Rob Kramer]

Hi,

When trying to find a deadlock in my program, I noticed my gdb (6.4 for 
i586-linux target, cross-compiled by OpenEmbedded) lacks thread support. It 
doesn't detect when a new thread starts, and 'info threads' always returns an 
empty list. Below is the output on i586-linux, versus a proper setup that 
works as expected:

OpenEmbedded distro (gdb 6.4):
--------------------
This GDB was configured as "i586-linux"...Using host libthread_db library 
"/lib/libthread_db.so.1".

(gdb) r 2
Starting program: /home/root/phello 2
Hello from node 0
Hello from node 1
--------------------


SUSE 10.1 (gdb 6.3):
--------------------
This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db 
library "/lib/libthread_db.so.1".

(gdb) r 2
Starting program: /home/rob/phello 2
[Thread debugging using libthread_db enabled]
[New Thread -1210440016 (LWP 13673)]
[New Thread -1210442848 (LWP 13676)]
Hello from node 0
Hello from node 1
--------------------


I've probably misconfigured or mis-crosscompiled my gdb, but how can I find 
out where I should start looking? Is there a way gdb can tell me why it 
doesn't support thread debugging? Do the config.{log|status} files record 
what might be wrong? (It all seems correct to me)

Glibc is version 2.4, (cross) gcc is 4.1.1, linux 2.6.16.27.

Cheers!

     Rob


-- 
1.8026175e+12 furlongs per fortnight.

Re: Missing thread support..

[Daniel Jacobowitz]

On Mon, Aug 14, 2006 at 11:52:23PM +0800, Rob Kramer wrote:
> Hi,
> 
> When trying to find a deadlock in my program, I noticed my gdb (6.4 for 
> i586-linux target, cross-compiled by OpenEmbedded) lacks thread support. It 
> doesn't detect when a new thread starts, and 'info threads' always returns an 
> empty list. Below is the output on i586-linux, versus a proper setup that 
> works as expected:
> 
> OpenEmbedded distro (gdb 6.4):
> --------------------
> This GDB was configured as "i586-linux"...Using host libthread_db library 
> "/lib/libthread_db.so.1".

No, if your GDB didn't have thread support, it wouldn't have loaded
libthread_db.

OpenEmbedded has probably got a broken libthread_db, or an excessively
stripped libpthread.so.

-- 
Daniel Jacobowitz
CodeSourcery

Re: Missing thread support..

[Rob Kramer]

On Tuesday 15 August 2006 04:58, Daniel Jacobowitz wrote:
> No, if your GDB didn't have thread support, it wouldn't have loaded
> libthread_db.
>
> OpenEmbedded has probably got a broken libthread_db, or an excessively
> stripped libpthread.so.

[x64] ~/oe/build-epia/tmp> file rootfs/lib/libthread_db-1.0.so
rootfs/lib/libthread_db-1.0.so: ELF 32-bit LSB shared object, Intel 80386, 
version 1 (SYSV), for GNU/Linux 2.6.15, stripped

Ah, you are correct, no symbols at all..

Thanks!

    Rob

-- 
1.8026175e+12 furlongs per fortnight.