Re: [PATCH] libxl: Don't segfault on soft-reset failure

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Thu, Mar 31, 2022 at 10:10 AM Anthony PERARD
<anthony.perard@xxxxxxxxxx> wrote:
>
> On Wed, Mar 30, 2022 at 02:17:27PM -0400, Jason Andryuk wrote:
> > diff --git a/tools/libs/light/libxl_create.c 
> > b/tools/libs/light/libxl_create.c
> > index 15ed021f41..631caa416d 100644
> > --- a/tools/libs/light/libxl_create.c
> > +++ b/tools/libs/light/libxl_create.c
> > @@ -1970,7 +1970,8 @@ static void domcreate_complete(libxl__egc *egc,
> >      libxl_domain_config *const d_config = dcs->guest_config;
> >      libxl_domain_config *d_config_saved = &dcs->guest_config_saved;
> >
> > -    libxl__xswait_stop(gc, &dcs->console_xswait);
> > +    if (dcs->console_xswait.path)
> > +        libxl__xswait_stop(gc, &dcs->console_xswait);
>
> libxl__xswait_stop() needs to be called here. It's a function that can
> be called several time without ill effect, as long as `console_xswait`
> is initialised properly (by calling libxl__xswait_init() like you did
> below.
>
> >      libxl__domain_build_state_dispose(&dcs->build_state);
> >
> > @@ -2176,6 +2177,10 @@ static int do_domain_soft_reset(libxl_ctx *ctx,
> >                                aop_console_how);
> >      cdcs->domid_out = &domid_out;
> >
> > +    /* Initialize in case we end up in domcreate_complete without calling
> > +     * initiate_domain_create. */
>
> That comment isn't needed. This is just part of the initialisation of
> `cdcs->dcs`.
>
> > +    libxl__xswait_init(&cdcs->dcs.console_xswait);
> > +
> >      dom_path = libxl__xs_get_dompath(gc, domid);
> >      if (!dom_path) {
> >          LOGD(ERROR, domid, "failed to read domain path");
>
>
> As part of the patch, could you also move the libxl__xswait_init() call
> in initiate_domain_create() to do_domain_create()? That would avoid
> `console_xswait` been initialised twice, and do_domain_create() is the
> function that initialise `dcs` before calling initiate_domain_create().

Sure, that all sounds good.  Thanks!

Regards,
Jason