Re: [Libunwind-devel] [PATCHv3 1/4] Add core dump unwinding support to libunwind

[Konstantin Belousov]

On Tue, Mar 13, 2012 at 08:06:37AM -0700, Arun Sharma wrote:
> On Tue, Mar 13, 2012 at 5:11 AM, Konstantin Belousov
> <address@hidden> wrote:
> 
> >> * tests/test-coredump-unwind doesn't test anything right now. An
> >> actual test that fails if future commits break things would be great.
> >> This might require a test core dump file for every platform you care
> >> about.
> > I think it is requirement to generate a coredump on machine where the
> > testing is performed.
> 
> You're right. I don't think coredump unwinding on another platform is 
> supported.
Not just platform, but I expect that exact versions of all objects
participated in the dumped image shall be the same.

> 
> >> People working on other platforms: please verify that this works for
> >> you (or at least doesn't break anything).
> > It does break build.
> > Please look at http://people.freebsd.org/~kib/git/libunwind.git/
> > branch coredump2, were I made it at least compilable for FreeBSD/i386
> > and FreeBSD/amd64.
> >
> > The commit 52a8e2119d86a55218b8bf131f46a78fdac861dd is probably wrong,
> > I do not have Linux machine to test.
> 
> Yes - it breaks Linux. I pulled everything up to dc9be1a into:
> 
> git://github.com/adsharma/libunwind.git (coredump2)

I hope that cc7c74e691032b8c694d673dc1530c26ce801736 would be fine
for Linux too, the tip of the branch was forcibly updated.

> 
> >
> > I am not sure how to test the functionality.
> 
> The comments at the top of test-coredump-unwind might be useful. I
> recall getting some reasonable output in the last iteration of the
> patch.
> 
> *
>  * Run:
>  * objdump -sx COREDUMP
>  * eu-unstrip -n --core COREDUMP
>  *   figure out which segments in COREDUMP correspond to which mapped
> executable files
>  *   (binary and libraries), then supply them like this:
>  * ./example-core-unwind COREDUMP 3:/bin/crashed_program 6:/lib/libc.so.6 
> [...]

What is eu-unstrip ?

Hm, test-coredump-unwind.c needs some changes too. I will look at it later.

> 
> Denys: can you automate the objdump step or have the test figure out
> the right segment automatically?
> 
>  -Arun

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