[PATCH] Add Safe-Linking to fastbins and tcache

[Eyal Itkin]

Sorry about the indentations. The file has mixed tabs and spaces, sometimes
even in the same code line, which makes it hard to know what's right. In
each case I tried to mimick the behavior of the lines before / after my
addition.

Regarding the new issue in malloc_consolidate, I'm going over it now as it
didn't happen on my intel x64 environment. Will update you soon about it.


On Mon, 30 Mar 2020, 11:01 Andreas Schwab, <schwab@suse.de> wrote:

> On Mär 20 2020, Eyal Itkin via Libc-alpha wrote:
>
> > @@ -2960,7 +2979,10 @@ tcache_thread_shutdown (void)
> >        while (tcache_tmp->entries[i])
> >       {
> >         tcache_entry *e = tcache_tmp->entries[i];
> > -       tcache_tmp->entries[i] = e->next;
> > +      if (__glibc_unlikely (!aligned_OK (e)))
> > +        malloc_printerr ("tcache_thread_shutdown(): " \
> > +                         "unaligned tcache chunk detected");
> > +       tcache_tmp->entries[i] = REVEAL_PTR (e->next);
> >         __libc_free (e);
>
> Wrong indentation, extra backslash.
>
> > @@ -4196,11 +4226,15 @@ _int_free (mstate av, mchunkptr p, int have_lock)
> >           LIBC_PROBE (memory_tcache_double_free, 2, e, tc_idx);
> >           for (tmp = tcache->entries[tc_idx];
> >                tmp;
> > -              tmp = tmp->next)
> > +              tmp = REVEAL_PTR (tmp->next))
> > +        {
> > +           if (__glibc_unlikely (!aligned_OK (tmp)))
> > +             malloc_printerr ("free(): unaligned chunk detected in
> tcache 2");
> >             if (tmp == e)
> >               malloc_printerr ("free(): double free detected in tcache
> 2");
> >           /* If we get here, it was a coincidence.  We've wasted a
> >              few cycles, but don't abort.  */
> > +        }
>
> Wrong indentation.
>
> > @@ -4896,8 +4935,13 @@ int_mallinfo (mstate av, struct mallinfo *m)
> >
> >    for (i = 0; i < NFASTBINS; ++i)
> >      {
> > -      for (p = fastbin (av, i); p != 0; p = p->fd)
> > +      for (p = fastbin (av, i);
> > +           p != 0;
> > +           p = REVEAL_PTR (p->fd))
> >          {
> > +          if (__glibc_unlikely (!aligned_OK (p)))
> > +            malloc_printerr ("int_mallinfo(): " \
> > +                             "unaligned fastbin chunk detected");
>
> Extra backslash.
>
> > @@ -5437,8 +5481,11 @@ __malloc_info (int options, FILE *fp)
> >
> >             while (p != NULL)
> >               {
> > +          if (__glibc_unlikely (!aligned_OK (p)))
> > +            malloc_printerr ("__malloc_info(): " \
> > +                             "unaligned fastbin chunk detected");
> >                 ++nthissize;
>
> Wrong indentation, extra backslash.
>
> Andreas.
>
> --
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."
>