[maemo-developers] Getting a core dump from QEMU

[From: Juha Kallioinen]

ext Ludovic Courtès wrote:
> Hi,
> 
> Is there a way for QEMU (within Scratchbox) to dump cores?
> 
> That would be helpful since I happen to have a program that segfaults in
> QEMU but not on the raw hardware.  I suspect QEMU might be a little more
> susceptible than the actual hardware/software stack in some cases...

Hello,

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

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.

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 :-)

So please try to live with the fact that your program can crash in qemu, but 
runs just fine on the device. You should be a bit more worried if your 
program crashes on the X86 target of scratchbox, but then you'll have core 
dumps and other debugging aids like valgrind more easily available too.

Cheers,
  Juha

-- 
Juha Kallioinen                                               JID: kaltsi at ok