Hi, thanks for pointing it out :). I'll cross compile for arm64 it with different KASAN settings and fix any such errors. I did this a while ago and it went okay then, but there were so many rebases in the meantime I must have missed something. Kind regards Maciej Wieczór-Retman On 2025-08-13 at 15:48:32 +0100, Ada Couprie Diaz wrote: >Hi, > >On 12/08/2025 14:23, Maciej Wieczor-Retman wrote: >> From: Samuel Holland <samuel.holland@xxxxxxxxxx> >> >> Allow architectures to override KASAN_TAG_KERNEL in asm/kasan.h. This >> is needed on RISC-V, which supports 57-bit virtual addresses and 7-bit >> pointer tags. For consistency, move the arm64 MTE definition of >> KASAN_TAG_MIN to asm/kasan.h, since it is also architecture-dependent; >> RISC-V's equivalent extension is expected to support 7-bit hardware >> memory tags. >> >> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> >> Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx> >> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx> >> --- >> arch/arm64/include/asm/kasan.h | 6 ++++-- >> arch/arm64/include/asm/uaccess.h | 1 + >> include/linux/kasan-tags.h | 13 ++++++++----- >> 3 files changed, 13 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h >> index e1b57c13f8a4..4ab419df8b93 100644 >> --- a/arch/arm64/include/asm/kasan.h >> +++ b/arch/arm64/include/asm/kasan.h >> @@ -6,8 +6,10 @@ >> #include <linux/linkage.h> >> #include <asm/memory.h> >> -#include <asm/mte-kasan.h> >> -#include <asm/pgtable-types.h> >> + >> +#ifdef CONFIG_KASAN_HW_TAGS >> +#define KASAN_TAG_MIN 0xF0 /* minimum value for random tags */ >> +#endif >Building CONFIG_KASAN_HW_TAGS with -Werror on arm64 fails here >due to a warning about KASAN_TAG_MIN being redefined. > >On my side the error got triggered when compiling >arch/arm64/kernel/asm-offsets.c due to the ordering of some includes : >from <asm/processor.h>, <linux/kasan-tags.h> ends up being included >(by <asm/cpufeatures.h> including <asm/sysreg.h>) before <asm/kasan.h>. >(Build trace at the end for reference) > >Adding `#undef KASAN_TAG_MIN` before redefining the arch version >allows building CONFIG_KASAN_HW_TAGS on arm64 without >further issues, but I don't know if this is most appropriate fix.Thanks, Ada >--- > > CC arch/arm64/kernel/asm-offsets.s >In file included from ./arch/arm64/include/asm/processor.h:42, > from ./include/asm-generic/qrwlock.h:18, > from ./arch/arm64/include/generated/asm/qrwlock.h:1, > from ./arch/arm64/include/asm/spinlock.h:9, > from ./include/linux/spinlock.h:95, > from ./include/linux/mmzone.h:8, > from ./include/linux/gfp.h:7, > from ./include/linux/slab.h:16, > from ./include/linux/resource_ext.h:11, > from ./include/linux/acpi.h:13, > from ./include/acpi/apei.h:9, > from ./include/acpi/ghes.h:5, > from ./include/linux/arm_sdei.h:8, > from ./arch/arm64/kernel/asm-offsets.c:10: >./arch/arm64/include/asm/kasan.h:11: error: "KASAN_TAG_MIN" redefined [-Werror] > 11 | #define KASAN_TAG_MIN 0xF0 /* minimum value for random tags */ > | >In file included from ./arch/arm64/include/asm/sysreg.h:14, > from ./arch/arm64/include/asm/cputype.h:250, > from ./arch/arm64/include/asm/cache.h:43, > from ./include/vdso/cache.h:5, > from ./include/linux/cache.h:6, > from ./include/linux/slab.h:15: >./include/linux/kasan-tags.h:23: note: this is the location of the previous definition > 23 | #define KASAN_TAG_MIN 0x00 /* minimum value for random tags */ > | >
