[for-stable-4.19,v2,0/2] Backport patches to fix KASAN+LKDTM with recent clang on ARM64

Message

Nicolas Boichat March 20, 2021, 4:16 a.m. UTC

Backport 2 patches that are required to make KASAN+LKDTM work
with recent clang (patch 2/2 has a complete description).
Tested on our chromeos-4.19 branch.
Also compile tested on x86-64 and arm64 with gcc this time
around.

Patch 1/2 adds a guard around noinstr that matches upstream,
to prevent a build issue, and has some minor context conflicts.
Patch 2/2 is a clean backport.

These patches have been merged to 5.4 stable already. We might
need to backport to older stable branches, but this is what I
could test for now.

Changes in v2:
 - Guard noinstr macro by __KERNEL__ && !__ASSEMBLY__ to prevent
   expansion in linker script and match upstream.

Mark Rutland (1):
  lkdtm: don't move ctors to .rodata

Thomas Gleixner (1):
  vmlinux.lds.h: Create section for protection against instrumentation

 arch/powerpc/kernel/vmlinux.lds.S |  1 +
 drivers/misc/lkdtm/Makefile       |  2 +-
 drivers/misc/lkdtm/rodata.c       |  2 +-
 include/asm-generic/sections.h    |  3 ++
 include/asm-generic/vmlinux.lds.h | 10 ++++++
 include/linux/compiler.h          | 54 +++++++++++++++++++++++++++++++
 include/linux/compiler_types.h    |  6 ++++
 scripts/mod/modpost.c             |  2 +-
 8 files changed, 77 insertions(+), 3 deletions(-)

Comments

Greg KH March 20, 2021, 10:57 a.m. UTC | #1

On Sat, Mar 20, 2021 at 12:16:24PM +0800, Nicolas Boichat wrote:
> Backport 2 patches that are required to make KASAN+LKDTM work
> with recent clang (patch 2/2 has a complete description).
> Tested on our chromeos-4.19 branch.
> Also compile tested on x86-64 and arm64 with gcc this time
> around.
> 
> Patch 1/2 adds a guard around noinstr that matches upstream,
> to prevent a build issue, and has some minor context conflicts.
> Patch 2/2 is a clean backport.
> 
> These patches have been merged to 5.4 stable already. We might
> need to backport to older stable branches, but this is what I
> could test for now.

Ok, trying this again, let's see what breaks :)

thanks,

greg k-h