debugging threads

Hello,

I am trying to debug a multithreaded app and am having some problems. I've hunted around how to do this and have done the following:

Built uClibc with debug threads on so have a libthread_db.so Built gdbserver for target

I then execute gdbserver with:
gdbserver 192.168.42.15:2345 /usr/sbin/threaded_test

On the host machine I run:
~/buildroot/build_i686/staging_dir/usr/bin/i686-linux-gdb ~/threaded_test

Once gdb starts I point it to the shared libs with:
set solib-absolute-prefix ~/buildroot/project_build_i686/uclibc/root

Then connect to gdbserver with
target remote 192.168.42.101:2345

I am able to debug the application until a call to create a thread (pthread_create) when I get the following error:

Program received signal SIG32, Real-time event 32. 0xb7ef0175 in sigsuspend ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libc.so.0 (gdb) bt
#0 0xb7ef0175 in sigsuspend ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libc.so.0 #1 0xb7faf6a4 in __pthread_wait_for_restart_signal ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libpthread.so.0 #2 0xb7faf6cc in ?? ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libpthread.so.0 #3 0xb7fb6040 in ?? ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libpthread.so.0 #4 0xb7fb1de8 in ?? ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libpthread.so.0 #5 0xbf871718 in ?? ()
#6 0xb7fafda8 in pthread_create ()
from
/home/willw/buildroot/project_build_i686/uclibc/root/lib/libpthread.so.0 Backtrace stopped: frame did not save the PC

Can anyone tell me what step I am missing to get thread debugging working? From searching on the net it seems the libthread_db is needed but it doesn't seem to be loaded by gdb.

Many thanks,

Will.

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Will Wagner                                     will_wagner at carallon.com
Senior Project Engineer                  Office Tel: +44 (0)20 7371 2032
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
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I solved this, it was a problem with gdb & gdbserver not being rebuilt when you change the uClibc option to allow thread debugging. A rebuild from scratch fixed the problem.

Will.

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Will Wagner                                     will_wagner at carallon.com
Senior Project Engineer                  Office Tel: +44 (0)20 7371 2032
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
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