Re: gdb-6.5 produces infinite backtrace on ARM

[Michael Snyder <Michael dot Snyder at palmsource dot com>]

On Sat, 2006-08-19 at 01:24 -0400, Daniel Jacobowitz wrote:
> On Tue, Aug 15, 2006 at 08:40:54AM -0400, Daniel Jacobowitz wrote:
> > Normally you should get an ugly end of the backtrace, not an infinite
> > one.  If you'd like, I can take a look at what's gone wrong.  I would
> > need enough to reproduce the problem - which probably means a tarball
> > including the source, compiled executable, and shared libraries which
> > it uses, since this may be specific to something about your build
> > environment.  If you want to do that, let me know; it's too big to post
> > to the list.
> 
> Thanks a lot for the test case.  The underlying cause was that
> pthread_start_thread is marked noreturn; GCC seems to have omitted
> the LR register save in this case.  I thought it wouldn't do that,
> but in any case, we should cope.
> 
> I know have a fairly general patch set for this problem, which
> produces:
> 
> (gdb) bt
> ...
> #4 0xxxxxxxx in pthread_start_thread () from /lib/libpthread.so.0
> Backtrace stopped: frame did not save the PC
> (gdb)
> 
> This isn't ideal - we could detect the pthread_start_thread function
> name and stop automatically, which might be a wise addition - but it's
> better than going off into the woods.
> 
> There's about 250 lines of changes involved, to one of the more
> complicated parts of GDB, so I will need to go over the patches again
> and post them separately.  But I'll try to make sure this is fixed
> soon.

Daniel, did you ever get around to posting your patch?

I have now run into this self-same problem myself, and 
would be glad to work with you on getting it handled.
Rather not duplicate effort, though...

Thanks,
Michael