Re: GDB, pthreads, and kernel threads

From: John Clark
Date: Wed May 18 2005 - 11:35:24 EST


Nix wrote:

On 18 May 2005, John Clark announced authoritatively:


Most of my work has been in the kernel and I had not paid attention to
user 'threads'. However, I have at the moment to a need to debug a
user 'pthread' based applicaiton, that I may want to move into the kernel.

However, I can't seem to figure out how to get GDB to debug my user
pthreads app. What is the correct setup to debug pthreads based applications
now that it seems that pthreads implementation generates processes/threads
in the kernel.



Use a recent GDB (>=6.2) and things should just work. (At least, they do
for me.)



I built the latest GDB-6.3, as well as rebuilt glibc-2.3.5, and now when I step through the
main code line, which creates the tasks (I'm using the pthreads.c from the GDB testsuite), I do
not getany output from:

info threads

When I set a break point on the entry point of one of the soon-to-be-created threads,
I get a diagnostic message:

Program terminated with signal SIGTRAP, Trace/Breakpoint trap.
The program no longer exists.


On the machine being used to debug the kernel is: 2.6.5.

Is there any problems with that kernel, or should I upgrade to a more recent vintage
version?

Thanks
John Clark

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