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Message-Id: <20250805142622.560992-1-snovitoll@gmail.com>
Date: Tue, 5 Aug 2025 19:26:13 +0500
From: Sabyrzhan Tasbolatov <snovitoll@...il.com>
To: ryabinin.a.a@...il.com,
hca@...ux.ibm.com,
christophe.leroy@...roup.eu,
andreyknvl@...il.com,
agordeev@...ux.ibm.com,
akpm@...ux-foundation.org,
zhangqing@...ngson.cn,
chenhuacai@...ngson.cn,
trishalfonso@...gle.com,
davidgow@...gle.com
Cc: glider@...gle.com,
dvyukov@...gle.com,
kasan-dev@...glegroups.com,
linux-kernel@...r.kernel.org,
loongarch@...ts.linux.dev,
linuxppc-dev@...ts.ozlabs.org,
linux-riscv@...ts.infradead.org,
linux-s390@...r.kernel.org,
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snovitoll@...il.com
Subject: [PATCH v4 0/9] kasan: unify kasan_arch_is_ready() and remove arch-specific implementations
This patch series addresses the fragmentation in KASAN initialization
across architectures by introducing a unified approach that eliminates
duplicate static keys and arch-specific kasan_arch_is_ready()
implementations.
The core issue is that different architectures have inconsistent approaches
to KASAN readiness tracking:
- PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready()
- Only HW_TAGS mode had a unified static key (kasan_flag_enabled)
- Generic and SW_TAGS modes relied on arch-specific solutions
or always-on behavior
This series implements two-level approach:
1. kasan_enabled() - compile-time check for KASAN configuration
2. kasan_shadow_initialized() - runtime check for shadow memory readiness
Changes in v4:
- Unified patches where ARCH_DEFER_KASAN is introduced and used
in the KASAN code (Andrey Ryabinin)
- Fixed kasan_enable() for HW_TAGS mode (Andrey Ryabinin)
- Replaced !kasan_enabled() with !kasan_shadow_initialized() in
loongarch which selects ARCH_DEFER_KASAN (Andrey Ryabinin)
- Addressed the issue in UML arch, where kasan_init_generic() is
called before jump_label_init() (Andrey Ryabinin)
Adding in TO additional recipients who developed KASAN in LoongArch, UML.
Tested on:
- powerpc - selects ARCH_DEFER_KASAN
Built ppc64_defconfig (PPC_BOOK3S_64) - OK
Booted via qemu-system-ppc64 - OK
- um - selects ARCH_DEFER_KASAN
Built defconfig with KASAN_INLINE - OK
Built defconfig with STATIC_LINK && KASAN_OUTLINE - OK
Booted ./linux - OK
- loongarch - selects ARCH_DEFER_KASAN
Built defconfig with KASAN_GENERIC - OK
Haven't tested the boot. Asking Loongarch developers to verify - N/A
But should be good, since Loongarch does not have specific "kasan_init()"
call like UML does. It selects ARCH_DEFER_KASAN and calls kasan_init()
in the end of setup_arch() after jump_label_init().
- arm64
Built defconfig, kvm_guest.config with HW_TAGS, SW_TAGS, GENERIC - OK
KASAN_KUNIT_TEST - OK
Booted via qemu-system-arm64 - OK
- x86_64
Built defconfig, kvm_guest.config with KASAN_GENERIC - OK
KASAN_KUNIT_TEST - OK
Booted via qemu-system-x86 - OK
- s390, riscv, xtensa, arm
Built defconfig with KASAN_GENERIC - OK
Previous v3 thread: https://lore.kernel.org/all/20250717142732.292822-1-snovitoll@gmail.com/
Previous v2 thread: https://lore.kernel.org/all/20250626153147.145312-1-snovitoll@gmail.com/
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
Sabyrzhan Tasbolatov (9):
kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
kasan/powerpc: select ARCH_DEFER_KASAN and call kasan_init_generic
kasan/arm,arm64: call kasan_init_generic in kasan_init
kasan/xtensa: call kasan_init_generic in kasan_init
kasan/loongarch: select ARCH_DEFER_KASAN and call kasan_init_generic
kasan/um: select ARCH_DEFER_KASAN and call kasan_init_generic
kasan/x86: call kasan_init_generic in kasan_init
kasan/s390: call kasan_init_generic in kasan_init
kasan/riscv: call kasan_init_generic in kasan_init
arch/arm/mm/kasan_init.c | 2 +-
arch/arm64/mm/kasan_init.c | 4 +--
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/kasan.h | 7 -----
arch/loongarch/mm/kasan_init.c | 8 ++---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/kasan.h | 12 --------
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/Kconfig | 1 +
arch/um/include/asm/kasan.h | 5 ---
arch/um/kernel/mem.c | 12 ++++++--
arch/x86/mm/kasan_init_64.c | 2 +-
arch/xtensa/mm/kasan_init.c | 2 +-
include/linux/kasan-enabled.h | 36 +++++++++++++++++-----
include/linux/kasan.h | 42 ++++++++++++++++++++------
lib/Kconfig.kasan | 8 +++++
mm/kasan/common.c | 18 +++++++----
mm/kasan/generic.c | 23 ++++++++------
mm/kasan/hw_tags.c | 9 +-----
mm/kasan/kasan.h | 36 ++++++++++++++++------
mm/kasan/shadow.c | 32 +++++---------------
mm/kasan/sw_tags.c | 4 ++-
mm/kasan/tags.c | 2 +-
27 files changed, 157 insertions(+), 124 deletions(-)
--
2.34.1
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