Re: [Qemu-devel] User emulation & gdb & sigsegv

["Edgar E. Iglesias" <edgar.iglesias@axis.com>]

On Thu, Dec 11, 2008 at 10:42:10PM +0100, Lionel Landwerlin wrote:
> Le jeudi 11 décembre 2008 à 00:18 +0100, Edgar E. Iglesias a écrit :
> > On Thu, Dec 11, 2008 at 12:06:53AM +0100, Lionel Landwerlin wrote:
> > > Hello,
> > > 
> > > Currently, when using gdb connected to qemu, if a sigsegv is raised,
> > > Qemu just exits.
> > > 
> > > How should I modify Qemu to redirect this last signal to the connected
> > > gdb and print a stack trace at least ?
> > > 
> > > I tried to call gdb_handlesig(gdbstub.c) from
> > > force_sig(linux-user/signal.c) but Qemu just crashes.
> > > 
> > > Any idea is welcome :)
> > 
> > Hello,
> > 
> > I've got this in my git, IIRC it helped me out in those situations.
> > 
> > Cheers
> > 
> > commit 1efa40a743e16dbe2803a8d16902bf89850e80a3
> > Author: Edgar E. Iglesias <edgar.iglesias@axis.com>
> > Date:   Mon Sep 29 14:14:24 2008 +0200
> > 
> >     Pass default handler signals to gdb aswell.
> > 
> > diff --git a/linux-user/signal.c b/linux-user/signal.c
> > index 9640923..b7d22a1 100644
> > --- a/linux-user/signal.c
> > +++ b/linux-user/signal.c
> > @@ -365,6 +365,7 @@ int queue_signal(CPUState *env, int sig, target_siginfo_t *info)
> >          if (sig != TARGET_SIGCHLD &&
> >              sig != TARGET_SIGURG &&
> >              sig != TARGET_SIGWINCH) {
> > +	    sig = gdb_handlesig(env, sig);
> >              force_sig(sig);
> >          } else {
> >              return 0; /* indicate ignored */
> > 
> > 
> 
> In fact this patch just make qemu crash too.
> Have you tested this patch on the current svn  ?

Nope, it's on my git with other patches, don't know if there are
dependencies. Feel free to have a look at
git://repo.or.cz/qemu/cris-port.git if you're interested. No
guarantees that it will help though :)

> What cpu did you use to test it ?

I run it on CRIS all the time.

Regards