Re: [PATCH v2] recordmcount: support >64k sections

[Kees Cook <keescook@chromium.org>]

On Fri, Apr 24, 2020 at 03:22:14PM -0700, Matt Helsley wrote:
> On Fri, Apr 24, 2020 at 12:30:46PM -0700, Sami Tolvanen wrote:
> > When compiling a kernel with Clang and LTO, we need to run
> > recordmcount on vmlinux.o with a large number of sections, which
> > currently fails as the program doesn't understand extended
> > section indexes. This change adds support for processing binaries
> > with >64k sections.
> > 
> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> 
> Feel free to add
> 
> Reviewed-by: Matt Helsley <mhelsley@vmware.com>

Hi!

Can this patch please be applied and sent before -rc2? FGKASLR, LTO, and
link time improvements[1] all depend on this fix, and I'd really like
them all to be able to sanely rebase for the development window.

Thanks!

-Kees

[1] https://lore.kernel.org/lkml/CAK7LNARbZhoaA=Nnuw0=gBrkuKbr_4Ng_Ei57uafujZf7Xazgw@mail.gmail.com/

> 
> > ---
> > Changes in v2:
> >  - Switched to unsigned int for (old|new)_shnum in append_func.
> >  - Added set_shnum and find_symtab helper functions and moved
> >    the new logic there.
> > 
> > ---
> >  scripts/recordmcount.h | 98 +++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 92 insertions(+), 6 deletions(-)
> 
> <snip>

-- 
Kees Cook