Re: [PATCH v1 1/7] elf-ops: bail out if we have no function symbols

[Philippe Mathieu-Daudé]

On 3/27/20 11:53 AM, Philippe Mathieu-Daudé wrote:
> On 3/27/20 10:49 AM, Alex Bennée wrote:
> > It's perfectly possible to have no function symbols in your elf file
> > and if we do the undefined behaviour sanitizer rightly complains about
> > us passing NULL to qsort. Check nsyms before we go ahead.
> >
> > Signed-off-by: Alex Bennée <address@hidden>
> > ---
> >   include/hw/elf_ops.h | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
> > index a1411bfcab6..b5d4074d1e3 100644
> > --- a/include/hw/elf_ops.h
> > +++ b/include/hw/elf_ops.h
> > @@ -170,8 +170,13 @@ static int glue(load_symbols, SZ)(struct elfhdr 
> > *ehdr, int fd, int must_swab,
> >           }
> >           i++;
> >       }
> > -    syms = g_realloc(syms, nsyms * sizeof(*syms));

Something was bugging me why looking at this line, now I remembered: 
another patch from 2 years ago :)

https://www.mail-archive.com/address@hidden/msg528713.html

Is this the same emitted warning? It seems.

  $ qemu-system-xtensa -M kc705 -m 128M -semihosting -nographic 
-monitor null -kernel Image.elf
  include/hw/elf_ops.h:179:5: runtime error: null pointer passed as 
argument 1, which is declared to never be null

If so, can you add it to the commit description?

Thanks!

> > +    /* check we have symbols left */
> > +    if (nsyms == 0) {
> > +        goto fail;
> > +    }
> > +
> > +    syms = g_realloc(syms, nsyms * sizeof(*syms));
> >       qsort(syms, nsyms, sizeof(*syms), glue(symcmp, SZ));
> >       for (i = 0; i < nsyms - 1; i++) {
> >           if (syms[i].st_size == 0) {
>
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>