Re: [PATCH 13/17 v5] xen/arm: vpl011: Modify xenconsole to support multiple consoles

[Wei Liu <wei.liu2@citrix.com>]

On Fri, Jul 07, 2017 at 07:22:14PM +0530, Bhupinder Thakur wrote:
> >> -static struct domain *create_domain(int domid)
> >> +static int console_init(struct console *con, struct domain *dom, void **data)
> >>  {
> >> -     struct domain *dom;
> >>       char *s;
> >> +     int err = -1;
> >>       struct timespec ts;
> >> -     struct console *con;
> >> +     struct console_data **con_data = (struct console_data **)data;
> >> +     char *xsname;
> >>
> >>       if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
> >>               dolog(LOG_ERR, "Cannot get time of day %s:%s:L%d",
> >>                     __FILE__, __FUNCTION__, __LINE__);
> >> -             return NULL;
> >> +             return err;
> >> +     }
> >> +
> >
> > There is a danger that you return at this point, the cleanup path in
> > caller will free garbage.
> >
> > I suggest you at least initialise all pointers to NULL at the beginning.
> >
> I am checking that the pointer is not null before freeing them.
> 

I'm not sure what your reply means.

Without initialising the pointers to NULL you can have garbage in your
pointer (currently only xspath) -- you end up freeing the garbage
pointer. That's why I made the suggestion in the first place. Checking
NULL isn't going to help that.

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