Hi,
On 12/08/2025 14:23, Maciej Wieczor-Retman wrote:
> [...]
> ======= Testing
> Checked all the kunits for both software tags and generic KASAN after
> making changes.
>
> In generic mode the results were:
>
> kasan: pass:59 fail:0 skip:13 total:72
> Totals: pass:59 fail:0 skip:13 total:72
> ok 1 kasan
>
> and for software tags:
>
> kasan: pass:63 fail:0 skip:9 total:72
> Totals: pass:63 fail:0 skip:9 total:72
> ok 1 kasan
I tested the series on arm64 and after fixing the build issues mentioned
I was able to boot without issues and did not observe any regressions
in the KASAN KUnit tests with either generic or software tags.
So this is Tested-by: Ada Couprie Diaz <ada.coupriediaz@arm.com> (For arm64)
I will note that the tests `kmalloc_memmove_negative_size` and
`kmalloc_memmove_invalid_size` seem to be able to corrupt memory
and lead to kernel crashes if `memmove()` is not properly instrumented,
which I discovered while investigating [0].
> [...]
> ======= Compilation
> Clang was used to compile the series (make LLVM=1) since gcc doesn't
> seem to have support for KASAN tag-based compiler instrumentation on
> x86.
Interestingly, while investigating [0], this comment slipped by me and
I managed to compile your series for x86 with software tags using GCC,
though it is a bit hacky.
You need to update the CC_HAS_KASAN_SW_TAGS to pass `-mlam=u48`
or `-mlam=u57`, as it is disabled by default, and pass `-march=arrowlake`
for compilation (the support for software tags depends on the arch).
You could then test with GCC (though the issue in [0] also applies to x86).
Best,
Ada
[0]: https://groups.google.com/g/kasan-dev/c/v1PYeoitg88
> ======= Dependencies
> The base branch for the series is the mainline kernel, tag 6.17-rc1.
>
> ======= Enabling LAM for testing
> Since LASS is needed for LAM and it can't be compiled without it I
> applied the LASS series [1] first, then applied my patches.
>
> [1] https://lore.kernel.org/all/20250707080317.3791624-1-kirill.shutemov@linux.intel.com/
>
> Changes v4:
> - Revert x86 kasan_mem_to_shadow() scheme to the same on used in generic
> KASAN. Keep the arithmetic shift idea for the KASAN in general since
> it makes more sense for arm64 and in risc-v.
> - Fix inline mode but leave it unavailable until a complementary
> compiler patch can be merged.
> - Apply Dave Hansen's comments on series formatting, patch style and
> code simplifications.
>
> Changes v3:
> - Remove the runtime_const patch and setup a unified offset for both 5
> and 4 paging levels.
> - Add a fix for inline mode on x86 tag-based KASAN. Add a handler for
> int3 that is generated on inline tag mismatches.
> - Fix scripts/gdb/linux/kasan.py so the new signed mem_to_shadow() is
> reflected there.
> - Fix Documentation/arch/arm64/kasan-offsets.sh to take new offsets into
> account.
> - Made changes to the kasan_non_canonical_hook() according to upstream
> discussion.
> - Remove patches 2 and 3 since they related to risc-v and this series
> adds only x86 related things.
> - Reorder __tag_*() functions so they're before arch_kasan_*(). Remove
> CONFIG_KASAN condition from __tag_set().
>
> Changes v2:
> - Split the series into one adding KASAN tag-based mode (this one) and
> another one that adds the dense mode to KASAN (will post later).
> - Removed exporting kasan_poison() and used a wrapper instead in
> kasan_init_64.c
> - Prepended series with 4 patches from the risc-v series and applied
> review comments to the first patch as the rest already are reviewed.
>
> Maciej Wieczor-Retman (16):
> kasan: Fix inline mode for x86 tag-based mode
> x86: Add arch specific kasan functions
> kasan: arm64: x86: Make special tags arch specific
> x86: Reset tag for virtual to physical address conversions
> mm: x86: Untag addresses in EXECMEM_ROX related pointer arithmetic
> x86: Physical address comparisons in fill_p*d/pte
> x86: KASAN raw shadow memory PTE init
> x86: LAM compatible non-canonical definition
> x86: LAM initialization
> x86: Minimal SLAB alignment
> kasan: arm64: x86: Handle int3 for inline KASAN reports
> kasan: x86: Apply multishot to the inline report handler
> kasan: x86: Logical bit shift for kasan_mem_to_shadow
> mm: Unpoison pcpu chunks with base address tag
> mm: Unpoison vms[area] addresses with a common tag
> x86: Make software tag-based kasan available
>
> Samuel Holland (2):
> kasan: sw_tags: Use arithmetic shift for shadow computation
> kasan: sw_tags: Support tag widths less than 8 bits
>
> Documentation/arch/arm64/kasan-offsets.sh | 8 ++-
> Documentation/arch/x86/x86_64/mm.rst | 6 +-
> MAINTAINERS | 4 +-
> arch/arm64/Kconfig | 10 ++--
> arch/arm64/include/asm/kasan-tags.h | 9 +++
> arch/arm64/include/asm/kasan.h | 6 +-
> arch/arm64/include/asm/memory.h | 14 ++++-
> arch/arm64/include/asm/uaccess.h | 1 +
> arch/arm64/kernel/traps.c | 17 +-----
> arch/arm64/mm/kasan_init.c | 7 ++-
> arch/x86/Kconfig | 4 +-
> arch/x86/boot/compressed/misc.h | 1 +
> arch/x86/include/asm/cache.h | 4 ++
> arch/x86/include/asm/kasan-tags.h | 9 +++
> arch/x86/include/asm/kasan.h | 71 ++++++++++++++++++++++-
> arch/x86/include/asm/page.h | 24 +++++++-
> arch/x86/include/asm/page_64.h | 2 +-
> arch/x86/kernel/alternative.c | 4 +-
> arch/x86/kernel/head_64.S | 3 +
> arch/x86/kernel/setup.c | 2 +
> arch/x86/kernel/traps.c | 4 ++
> arch/x86/mm/Makefile | 2 +
> arch/x86/mm/init.c | 3 +
> arch/x86/mm/init_64.c | 11 ++--
> arch/x86/mm/kasan_init_64.c | 19 +++++-
> arch/x86/mm/kasan_inline.c | 26 +++++++++
> arch/x86/mm/pat/set_memory.c | 1 +
> arch/x86/mm/physaddr.c | 1 +
> include/linux/kasan-tags.h | 21 +++++--
> include/linux/kasan.h | 51 +++++++++++++++-
> include/linux/mm.h | 6 +-
> include/linux/mmzone.h | 1 -
> include/linux/page-flags-layout.h | 9 +--
> lib/Kconfig.kasan | 3 +-
> mm/execmem.c | 4 +-
> mm/kasan/hw_tags.c | 11 ++++
> mm/kasan/report.c | 45 ++++++++++++--
> mm/kasan/shadow.c | 18 ++++++
> mm/vmalloc.c | 8 +--
> scripts/Makefile.kasan | 3 +
> scripts/gdb/linux/kasan.py | 5 +-
> scripts/gdb/linux/mm.py | 5 +-
> 42 files changed, 381 insertions(+), 82 deletions(-)
> mode change 100644 => 100755 Documentation/arch/arm64/kasan-offsets.sh
> create mode 100644 arch/arm64/include/asm/kasan-tags.h
> create mode 100644 arch/x86/include/asm/kasan-tags.h
> create mode 100644 arch/x86/mm/kasan_inline.c
>