[v2,00/33] kmsan: Enable on s390

Message

Ilya Leoshkevich Nov. 21, 2023, 10 p.m. UTC

v1: https://lore.kernel.org/lkml/[e-mail]/
v1 -> v2: Add comments, sort #includes, introduce
          memset_no_sanitize_memory() and use it to avoid unpoisoning
          of redzones, change vmalloc alignment to _REGION3_SIZE, add
          R-bs (Alexander P.).

          Fix building
          [PATCH 28/33] s390/string: Add KMSAN support
          with FORTIFY_SOURCE.
          Reported-by: kernel test robot <[e-mail]>
          Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/

Hi,

This series provides the minimal support for Kernel Memory Sanitizer on
s390. Kernel Memory Sanitizer is clang-only instrumentation for finding
accesses to uninitialized memory. The clang support for s390 has already
been merged [1].

With this series, I can successfully boot s390 defconfig and
debug_defconfig with kmsan.panic=1. The tool found one real
s390-specific bug (fixed in master).

Best regards,
Ilya

[1] https://reviews.llvm.org/D148596

Ilya Leoshkevich (33):
  ftrace: Unpoison ftrace_regs in ftrace_ops_list_func()
  kmsan: Make the tests compatible with kmsan.panic=1
  kmsan: Disable KMSAN when DEFERRED_STRUCT_PAGE_INIT is enabled
  kmsan: Increase the maximum store size to 4096
  kmsan: Fix is_bad_asm_addr() on arches with overlapping address spaces
  kmsan: Fix kmsan_copy_to_user() on arches with overlapping address
    spaces
  kmsan: Remove a useless assignment from
    kmsan_vmap_pages_range_noflush()
  kmsan: Remove an x86-specific #include from kmsan.h
  kmsan: Introduce kmsan_memmove_metadata()
  kmsan: Expose kmsan_get_metadata()
  kmsan: Export panic_on_kmsan
  kmsan: Allow disabling KMSAN checks for the current task
  kmsan: Introduce memset_no_sanitize_memory()
  kmsan: Support SLAB_POISON
  kmsan: Use ALIGN_DOWN() in kmsan_get_metadata()
  mm: slub: Let KMSAN access metadata
  mm: kfence: Disable KMSAN when checking the canary
  lib/string: Add KMSAN support to strlcpy() and strlcat()
  lib/zlib: Unpoison DFLTCC output buffers
  kmsan: Accept ranges starting with 0 on s390
  s390: Turn off KMSAN for boot, vdso and purgatory
  s390: Use a larger stack for KMSAN
  s390/boot: Add the KMSAN runtime stub
  s390/checksum: Add a KMSAN check
  s390/cpacf: Unpoison the results of cpacf_trng()
  s390/ftrace: Unpoison ftrace_regs in kprobe_ftrace_handler()
  s390/mm: Define KMSAN metadata for vmalloc and modules
  s390/string: Add KMSAN support
  s390/traps: Unpoison the kernel_stack_overflow()'s pt_regs
  s390/uaccess: Add KMSAN support to put_user() and get_user()
  s390/unwind: Disable KMSAN checks
  s390: Implement the architecture-specific kmsan functions
  kmsan: Enable on s390

 Documentation/dev-tools/kmsan.rst   |   4 +-
 arch/s390/Kconfig                   |   1 +
 arch/s390/Makefile                  |   2 +-
 arch/s390/boot/Makefile             |   3 +
 arch/s390/boot/kmsan.c              |   6 ++
 arch/s390/boot/startup.c            |   8 ++
 arch/s390/boot/string.c             |  16 ++++
 arch/s390/include/asm/checksum.h    |   2 +
 arch/s390/include/asm/cpacf.h       |   2 +
 arch/s390/include/asm/kmsan.h       |  36 +++++++++
 arch/s390/include/asm/pgtable.h     |  10 +++
 arch/s390/include/asm/string.h      |  20 +++--
 arch/s390/include/asm/thread_info.h |   2 +-
 arch/s390/include/asm/uaccess.h     | 110 ++++++++++++++++++++--------
 arch/s390/kernel/ftrace.c           |   1 +
 arch/s390/kernel/traps.c            |   6 ++
 arch/s390/kernel/unwind_bc.c        |   4 +
 arch/s390/kernel/vdso32/Makefile    |   3 +-
 arch/s390/kernel/vdso64/Makefile    |   3 +-
 arch/s390/purgatory/Makefile        |   2 +
 include/linux/kmsan-checks.h        |  26 +++++++
 include/linux/kmsan.h               |  23 ++++++
 include/linux/kmsan_types.h         |   2 +-
 kernel/trace/ftrace.c               |   1 +
 lib/string.c                        |   6 ++
 lib/zlib_dfltcc/dfltcc.h            |   1 +
 lib/zlib_dfltcc/dfltcc_util.h       |  23 ++++++
 mm/Kconfig                          |   1 +
 mm/kfence/core.c                    |   5 +-
 mm/kmsan/core.c                     |   2 +-
 mm/kmsan/hooks.c                    |  30 +++++++-
 mm/kmsan/init.c                     |   5 +-
 mm/kmsan/instrumentation.c          |  11 +--
 mm/kmsan/kmsan.h                    |   9 +--
 mm/kmsan/kmsan_test.c               |   5 ++
 mm/kmsan/report.c                   |   7 +-
 mm/kmsan/shadow.c                   |   9 +--
 mm/slub.c                           |  12 ++-
 38 files changed, 345 insertions(+), 74 deletions(-)
 create mode 100644 arch/s390/boot/kmsan.c
 create mode 100644 arch/s390/include/asm/kmsan.h

Comments

Alexander Potapenko Dec. 11, 2023, 10:07 a.m. UTC | #1

> +static inline void *kmsan_get_metadata(void *addr, bool is_origin)
> +{
> +       return NULL;
> +}
> +
>  #endif

We shouldn't need this part, as kmsan_get_metadata() should never be
called in non-KMSAN builds.