Is this part of ATLAS fortran or some of the auto-tuned platform specific
code?

My default would be to check that you actually have unwind tables; I don't
recall if gfortran produces them by default. In addition to Arun's
suggestion, you can check that "readelf -WwF
/usr/local/atlas/lib/libsatlas.so" shows a FDE entry, stack movement and
register location information for the PC ranges of each of those functions.
"nm -D -n /usr/local/atlas/lib/libsatlas.so" will tell you the function
addresses to compare with.

As Arun suggested, using more verbose libunwind debugging will help too.



On Thu, Sep 4, 2014 at 3:59 AM, Arun Sharma <[email protected]> wrote:

> On Thu, Sep 4, 2014 at 5:42 AM, Scott Biersdorff <[email protected]>
> wrote:
> > Hi,
> >
> >
> > I am attempting to unwind from an optimized shared (non-stripped) library
> > compiled with debugging information. However I cannot unwind pass the
> second
> > entry on the call stack. Ideally I would like to unwind all the way back
> to
> > main and I understand libunwind has techniques it uses when and if the
> frame
> > pointers/dwarf information is unavailable and I want to make sure that
> I’m
> > using libunwind in such a way that gives it is the best possibility to
> use
> > these techniques. Here are some details:
> >
>
> I noticed that addresses in gdb stack trace and libunwind weren't the
> same. Perhaps turn off address space randomization in the kernel to
> compare the two unwinders?
>
> Other things I'd check:
>
> * Does the binary have .eh_frame section intact?
> * Any hand written asm function with missing unwind info?
> * Are async signals involved? If so, you'll need to compile with
> -fasynchronous-unwind-tables
>
> Also, at higher UNWIND_DEBUG_LEVELs you'll see more information about
> the point where libunwind switched from DWARF based unwinding to frame
> pointer based unwinding due to lack of debug info.
>
>  -Arun
>
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