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@xxxxxxx> (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@xxxxxxxxxxxxxxx/ 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
