Re: [PATCH 06/10] stubdom/xenstored: Fix uninitialised variables in lu_read_state()

[Jürgen Groß <jgross@xxxxxxxx>]

On 12.02.21 18:01, Andrew Cooper wrote:
> On 12/02/2021 16:08, Jürgen Groß wrote:
> > On 12.02.21 16:39, Andrew Cooper wrote:
> > > Various version of gcc, when compiling with -Og, complain:
> > >
> > >     xenstored_control.c: In function ‘lu_read_state’:
> > >     xenstored_control.c:540:11: error: ‘state.size’ is used
> > > uninitialized in this
> > >     function [-Werror=uninitialized]
> > >       if (state.size == 0)
> > >           ~~~~~^~~~~
> > >     xenstored_control.c:543:6: error: ‘state.buf’ may be used
> > > uninitialized in
> > >     this function [-Werror=maybe-uninitialized]
> > >       pre = state.buf;
> > >       ~~~~^~~~~~~~~~~
> > >     xenstored_control.c:550:23: error: ‘state.buf’ may be used
> > > uninitialized in
> > >     this function [-Werror=maybe-uninitialized]
> > >        (void *)head - state.buf < state.size;
> > >                       ~~~~~^~~~
> > >     xenstored_control.c:550:35: error: ‘state.size’ may be used
> > > uninitialized in
> > >     this function [-Werror=maybe-uninitialized]
> > >        (void *)head - state.buf < state.size;
> > >                                   ~~~~~^~~~~
> > >
> > > Interestingly, this is only in the stubdom build.  I can't identify any
> > > relevant differences vs the regular tools build.
> > But me. :-)
> >
> > lu_get_dump_state() is empty for the stubdom case (this will change when
> > LU is implemented for stubdom, too). In the daemon case this function is
> > setting all the fields which are relevant.
> So I spotted that.  This instance of lu_read_state() is already within
> the ifdefary, so doesn't get to see the empty stub (I think).
There is only one instance of lu_read_state().


Juergen

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