[maemo-developers] Getting a core dump from QEMU

[From: Ludovic Courtès]

Hi,

Juha Kallioinen <juha.kallioinen at nokia.com> writes:

> sorry I don't know how to get a core dump from qemu. I guess in your case 
> qemu just exits and says something like this:
>
> qemu: uncaught target signal 11 (Segmentation fault) - exiting

Right.

> Well you are right in guessing that qemu is not 100% matching the hardware. 
> In fact it's quite different from it. One major issue with it is that it's 
> internally not thread safe, so if your program, or a library your program is 
> using, is spawning threads then you'll get into trouble easily. Also 
> some/many system calls are unimplemented.

Indeed.  The package I was building (GNU Guile 1.8) was using threads.
Recompiling it with multi-threading disabled fixed the problem.

> In the maemo SDK, Qemu is only supposed to be used to *build* the ARMEL .deb 
> packages which are then runnable/installable on the device. The confusing 
> thing is that many programs do work in qemu, but still you should not really 
> use it to run them because of these known issues :-)

Actually, I was essentially running `dpkg-buildpackage' in Scratchbox
(ARMEL target), which runs the package's test suite.  Running the test
suite on the real hardware isn't an option I guess (well, I did it to
convince myself that QEMU might be wrong, but you wouldn't do it for
every single package that you build ;-)).  And running the test suite on
x86 or similar isn't as useful.

Thanks!

Ludovic.