[GIT PULL] x86-refcount fix for v4.14-rc3

[GIT PULL] x86-refcount fix for v4.14-rc3

[Kees Cook]

Hi,

Please pull this x86-refcount fix for v4.14-rc3. This restores the x86
fast-refcount protection after fixing a corner case that was found late
before the merge window opened. This was the only problem seen during
the protection's life in linux-next, so getting this into v4.14 is
highly desired.

Thanks!

-Kees

The following changes since commit e19b205be43d11bff638cad4487008c48d21c103:

  Linux 4.14-rc2 (2017-09-24 16:38:56 -0700)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git tags/x86-refcount-v4.14-rc3

for you to fetch changes up to 635fee8f6b725a99f511b8e0eca82c3214b9c678:

  locking/refcounts, x86/asm: Enable CONFIG_ARCH_HAS_REFCOUNT (2017-09-27 03:05:13 -0700)

----------------------------------------------------------------
Fix x86 fast-refcount protection to avoid corner-case of being used a
function living in the .text.unlikely section.

----------------------------------------------------------------
Kees Cook (2):
      locking/refcounts, x86/asm: Use unique .text section for refcount exceptions
      locking/refcounts, x86/asm: Enable CONFIG_ARCH_HAS_REFCOUNT

 arch/x86/Kconfig                  | 2 +-
 arch/x86/include/asm/refcount.h   | 2 +-
 arch/x86/mm/extable.c             | 7 ++++++-
 include/asm-generic/vmlinux.lds.h | 1 +
 4 files changed, 9 insertions(+), 3 deletions(-)

-- 
Kees Cook
Pixel Security

Re: [GIT PULL] x86-refcount fix for v4.14-rc3

[Ingo Molnar]

* Kees Cook <keescook@chromium.org> wrote:

> Hi,
> 
> Please pull this x86-refcount fix for v4.14-rc3. This restores the x86
> fast-refcount protection after fixing a corner case that was found late
> before the merge window opened. This was the only problem seen during
> the protection's life in linux-next, so getting this into v4.14 is
> highly desired.

No, this is clearly v4.15 material.

> Kees Cook (2):
>       locking/refcounts, x86/asm: Use unique .text section for refcount exceptions
>       locking/refcounts, x86/asm: Enable CONFIG_ARCH_HAS_REFCOUNT

Do these commits differ from what you sent as patches on Sep 2?

Thanks,

	Ingo

Re: [GIT PULL] x86-refcount fix for v4.14-rc3

[Kees Cook]

On Wed, Sep 27, 2017 at 12:57 PM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Kees Cook <keescook@chromium.org> wrote:
>
>> Hi,
>>
>> Please pull this x86-refcount fix for v4.14-rc3. This restores the x86
>> fast-refcount protection after fixing a corner case that was found late
>> before the merge window opened. This was the only problem seen during
>> the protection's life in linux-next, so getting this into v4.14 is
>> highly desired.
>
> No, this is clearly v4.15 material.

Given the long bake time in linux-next (with only the one bug), and
that the fix was done weeks ago, why the delay?

>> Kees Cook (2):
>>       locking/refcounts, x86/asm: Use unique .text section for refcount exceptions
>>       locking/refcounts, x86/asm: Enable CONFIG_ARCH_HAS_REFCOUNT
>
> Do these commits differ from what you sent as patches on Sep 2?

They are the same, but now that we've reached -rc2, there's no longer
the fuzz against the linker script changes, so it seemed like a better
way to send them your way.

-Kees

-- 
Kees Cook
Pixel Security

Re: [GIT PULL] x86-refcount fix for v4.14-rc3

[Ingo Molnar]

* Kees Cook <keescook@chromium.org> wrote:

> On Wed, Sep 27, 2017 at 12:57 PM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Kees Cook <keescook@chromium.org> wrote:
> >
> >> Hi,
> >>
> >> Please pull this x86-refcount fix for v4.14-rc3. This restores the x86
> >> fast-refcount protection after fixing a corner case that was found late
> >> before the merge window opened. This was the only problem seen during
> >> the protection's life in linux-next, so getting this into v4.14 is
> >> highly desired.
> >
> > No, this is clearly v4.15 material.
> 
> Given the long bake time in linux-next (with only the one bug), and
> that the fix was done weeks ago, why the delay?

Because it's essentially enabling a new feature and the merge window is over.
I'll apply them in 1-2 days.

Thanks,

	Ingo