This patch series unifies the kasan_arch_is_ready() and kasan_enabled() interfaces by extending the existing kasan_enabled() infrastructure to work consistently across all KASAN modes (Generic, SW_TAGS, HW_TAGS).
Currently, kasan_enabled() only works for HW_TAGS mode using a static key, while other modes either return IS_ENABLED(CONFIG_KASAN) (compile-time constant) or rely on architecture-specific kasan_arch_is_ready() implementations with custom static keys and global variables. This leads to: - Code duplication across architectures - Inconsistent runtime behavior between KASAN modes - Architecture-specific readiness tracking After this series: - All KASAN modes use the same kasan_flag_enabled static key - Consistent runtime enable/disable behavior across modes - Simplified architecture code with unified kasan_init_generic() calls - Elimination of arch specific kasan_arch_is_ready() implementations - Unified vmalloc integration using kasan_enabled() checks This addresses the bugzilla issue [1] about making kasan_flag_enabled and kasan_enabled() work for Generic mode, and extends it to provide true unification across all modes. [1] https://bugzilla.kernel.org/show_bug.cgi?id=217049 === Current mainline KUnit status To see if there is any regression, I've tested first on the following commit 739a6c93cc75 ("Merge tag 'nfsd-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux"). Tested via compiling a kernel with CONFIG_KASAN_KUNIT_TEST and running QEMU VM. There are failing tests in SW_TAGS and GENERIC modes in arm64: arm64 CONFIG_KASAN_HW_TAGS: # kasan: pass:62 fail:0 skip:13 total:75 # Totals: pass:62 fail:0 skip:13 total:75 ok 1 kasan arm64 CONFIG_KASAN_SW_TAGS=y: # kasan: pass:65 fail:1 skip:9 total:75 # Totals: pass:65 fail:1 skip:9 total:75 not ok 1 kasan # kasan_strings: EXPECTATION FAILED at mm/kasan/kasan_test_c.c:1598 KASAN failure expected in "strscpy(ptr, src + KASAN_GRANULE_SIZE, KASAN_GRANULE_SIZE)", but none occurred arm64 CONFIG_KASAN_GENERIC=y, CONFIG_KASAN_OUTLINE=y: # kasan: pass:61 fail:1 skip:13 total:75 # Totals: pass:61 fail:1 skip:13 total:75 not ok 1 kasan # same failure as above x86_64 CONFIG_KASAN_GENERIC=y: # kasan: pass:58 fail:0 skip:17 total:75 # Totals: pass:58 fail:0 skip:17 total:75 ok 1 kasan === Testing with patches Testing in v2: - Compiled every affected arch with no errors: $ make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \ OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \ HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld \ ARCH=$ARCH $ clang --version ClangBuiltLinux clang version 19.1.4 Target: x86_64-unknown-linux-gnu Thread model: posix - make ARCH=um produces the warning during compiling: MODPOST Module.symvers WARNING: modpost: vmlinux: section mismatch in reference: \ kasan_init+0x43 (section: .ltext) -> \ kasan_init_generic (section: .init.text) AFAIU, it's due to the code in arch/um/kernel/mem.c, where kasan_init() is placed in own section ".kasan_init", which calls kasan_init_generic() which is marked with "__init". - Booting via qemu-system- and running KUnit tests: * arm64 (GENERIC, HW_TAGS, SW_TAGS): no regression, same above results. * x86_64 (GENERIC): no regression, no errors === NB I haven't tested the kernel boot on the following arch. due to the absence of qemu-system- support on those arch on my machine, so I defer this to relevant arch people to test KASAN initialization: - loongarch - s390 - um - xtensa - powerpc - riscv Code changes in v2: - Replace the order of patches. Move "kasan: replace kasan_arch_is_ready with kasan_enabled" at the end to keep the compatibility. - arch/arm, arch/riscv: add 2 arch. missed in v1 - arch/powerpc: add kasan_init_generic() in other kasan_init() calls: arch/powerpc/mm/kasan/init_32.c arch/powerpc/mm/kasan/init_book3e_64.c - arch/um: add the proper header `#include <linux/kasan.h>`. Tested via compiling with no errors. In the v1 arch/um changes were acked-by Johannes Berg, though I don't include it due to the changed code in v2. - arch/powerpc: add back `#ifdef CONFIG_KASAN` deleted in v1 and tested the compilation. - arch/loongarch: update git commit message about non-standard flow of calling kasan_init_generic() Sabyrzhan Tasbolatov (11): kasan: unify static kasan_flag_enabled across modes kasan/arm64: call kasan_init_generic in kasan_init kasan/arm: call kasan_init_generic in kasan_init kasan/xtensa: call kasan_init_generic in kasan_init kasan/loongarch: call kasan_init_generic in kasan_init kasan/um: call kasan_init_generic in kasan_init kasan/x86: call kasan_init_generic in kasan_init kasan/s390: call kasan_init_generic in kasan_init kasan/powerpc: call kasan_init_generic in kasan_init kasan/riscv: call kasan_init_generic in kasan_init kasan: replace kasan_arch_is_ready with kasan_enabled arch/arm/mm/kasan_init.c | 2 +- arch/arm64/mm/kasan_init.c | 4 +--- arch/loongarch/include/asm/kasan.h | 7 ------- arch/loongarch/mm/kasan_init.c | 7 ++----- arch/powerpc/include/asm/kasan.h | 13 ------------- arch/powerpc/mm/kasan/init_32.c | 2 +- arch/powerpc/mm/kasan/init_book3e_64.c | 2 +- arch/powerpc/mm/kasan/init_book3s_64.c | 6 +----- arch/riscv/mm/kasan_init.c | 1 + arch/s390/kernel/early.c | 3 ++- arch/um/include/asm/kasan.h | 5 ----- arch/um/kernel/mem.c | 4 ++-- arch/x86/mm/kasan_init_64.c | 2 +- arch/xtensa/mm/kasan_init.c | 2 +- include/linux/kasan-enabled.h | 22 ++++++++++++++++------ include/linux/kasan.h | 6 ++++++ mm/kasan/common.c | 15 +++++++++++---- mm/kasan/generic.c | 17 ++++++++++++++--- mm/kasan/hw_tags.c | 7 ------- mm/kasan/kasan.h | 6 ------ mm/kasan/shadow.c | 15 +++------------ mm/kasan/sw_tags.c | 2 ++ 22 files changed, 66 insertions(+), 84 deletions(-) -- 2.34.1
