On Fri, Aug 8, 2025 at 10:03 AM Christophe Leroy
<christophe.le...@csgroup.eu> wrote:
>
>
>
> Le 07/08/2025 à 21:40, Sabyrzhan Tasbolatov a écrit :
> > Introduce CONFIG_ARCH_DEFER_KASAN to identify architectures [1] that need
> > to defer KASAN initialization until shadow memory is properly set up,
> > and unify the static key infrastructure across all KASAN modes.
>
> That probably desserves more details, maybe copy in informations from
> the top of cover letter.
>
> I think there should also be some exeplanations about
> kasan_arch_is_ready() becoming kasan_enabled(), and also why
> kasan_arch_is_ready() completely disappear from mm/kasan/common.c
> without being replaced by kasan_enabled().
>
> >
> > [1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN.
> >
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
> > Signed-off-by: Sabyrzhan Tasbolatov <snovit...@gmail.com>
> > ---
> > Changes in v5:
> > - Unified patches where arch (powerpc, UML, loongarch) selects
> > ARCH_DEFER_KASAN in the first patch not to break
> > bisectability
> > - Removed kasan_arch_is_ready completely as there is no user
> > - Removed __wrappers in v4, left only those where it's necessary
> > due to different implementations
> >
> > Changes in v4:
> > - Fixed HW_TAGS static key functionality (was broken in v3)
> > - Merged configuration and implementation for atomicity
> > ---
> > 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/um/Kconfig | 1 +
> > arch/um/include/asm/kasan.h | 5 ++--
> > arch/um/kernel/mem.c | 10 ++++++--
> > include/linux/kasan-enabled.h | 32 ++++++++++++++++++--------
> > include/linux/kasan.h | 6 +++++
> > lib/Kconfig.kasan | 8 +++++++
> > mm/kasan/common.c | 17 ++++++++++----
> > mm/kasan/generic.c | 19 +++++++++++----
> > mm/kasan/hw_tags.c | 9 +-------
> > mm/kasan/kasan.h | 8 ++++++-
> > mm/kasan/shadow.c | 12 +++++-----
> > mm/kasan/sw_tags.c | 1 +
> > mm/kasan/tags.c | 2 +-
> > 21 files changed, 100 insertions(+), 69 deletions(-)
> >
> > diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> > index f0abc38c40a..cd64b2bc12d 100644
> > --- a/arch/loongarch/Kconfig
> > +++ b/arch/loongarch/Kconfig
> > @@ -9,6 +9,7 @@ config LOONGARCH
> > select ACPI_PPTT if ACPI
> > select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
> > select ARCH_BINFMT_ELF_STATE
> > + select ARCH_DEFER_KASAN if KASAN
>
> Instead of adding 'if KASAN' in all users, you could do in two steps:
>
> Add a symbol ARCH_NEEDS_DEFER_KASAN.
>
> +config ARCH_NEEDS_DEFER_KASAN
> + bool
>
> And then:
>
> +config ARCH_DEFER_KASAN
> + def_bool
> + depends on KASAN
> + depends on ARCH_DEFER_KASAN
> + help
> + Architectures should select this if they need to defer KASAN
> + initialization until shadow memory is properly set up. This
> + enables runtime control via static keys. Otherwise, KASAN uses
> + compile-time constants for better performance.
>
Actually, I don't see the benefits from this option. Sorry, have just
revisited this again.
With the new symbol, arch (PowerPC, UML, LoongArch) still needs select
2 options:
select ARCH_NEEDS_DEFER_KASAN
select ARCH_DEFER_KASAN
and the oneline with `if` condition is cleaner.
select ARCH_DEFER_KASAN if KASAN
>
>
> > select ARCH_DISABLE_KASAN_INLINE
> > select ARCH_ENABLE_MEMORY_HOTPLUG
> > select ARCH_ENABLE_MEMORY_HOTREMOVE
> > diff --git a/arch/loongarch/include/asm/kasan.h
> > b/arch/loongarch/include/asm/kasan.h
> > index 62f139a9c87..0e50e5b5e05 100644
> > --- a/arch/loongarch/include/asm/kasan.h
> > +++ b/arch/loongarch/include/asm/kasan.h
> > @@ -66,7 +66,6 @@
> > #define XKPRANGE_WC_SHADOW_OFFSET (KASAN_SHADOW_START +
> > XKPRANGE_WC_KASAN_OFFSET)
> > #define XKVRANGE_VC_SHADOW_OFFSET (KASAN_SHADOW_START +
> > XKVRANGE_VC_KASAN_OFFSET)
> >
> > -extern bool kasan_early_stage;
> > extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
> >
> > #define kasan_mem_to_shadow kasan_mem_to_shadow
> > @@ -75,12 +74,6 @@ void *kasan_mem_to_shadow(const void *addr);
> > #define kasan_shadow_to_mem kasan_shadow_to_mem
> > const void *kasan_shadow_to_mem(const void *shadow_addr);
> >
> > -#define kasan_arch_is_ready kasan_arch_is_ready
> > -static __always_inline bool kasan_arch_is_ready(void)
> > -{
> > - return !kasan_early_stage;
> > -}
> > -
> > #define addr_has_metadata addr_has_metadata
> > static __always_inline bool addr_has_metadata(const void *addr)
> > {
> > diff --git a/arch/loongarch/mm/kasan_init.c b/arch/loongarch/mm/kasan_init.c
> > index d2681272d8f..170da98ad4f 100644
> > --- a/arch/loongarch/mm/kasan_init.c
> > +++ b/arch/loongarch/mm/kasan_init.c
> > @@ -40,11 +40,9 @@ static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata
> > __aligned(PAGE_SIZE);
> > #define __pte_none(early, pte) (early ? pte_none(pte) : \
> > ((pte_val(pte) & _PFN_MASK) == (unsigned
> > long)__pa(kasan_early_shadow_page)))
> >
> > -bool kasan_early_stage = true;
> > -
> > void *kasan_mem_to_shadow(const void *addr)
> > {
> > - if (!kasan_arch_is_ready()) {
> > + if (!kasan_enabled()) {
> > return (void *)(kasan_early_shadow_page);
> > } else {
> > unsigned long maddr = (unsigned long)addr;
> > @@ -298,7 +296,8 @@ void __init kasan_init(void)
> > kasan_populate_early_shadow(kasan_mem_to_shadow((void
> > *)VMALLOC_START),
> > kasan_mem_to_shadow((void
> > *)KFENCE_AREA_END));
> >
> > - kasan_early_stage = false;
> > + /* Enable KASAN here before kasan_mem_to_shadow(). */
> > + kasan_init_generic();
> >
> > /* Populate the linear mapping */
> > for_each_mem_range(i, &pa_start, &pa_end) {
> > @@ -329,5 +328,4 @@ void __init kasan_init(void)
> >
> > /* At this point kasan is fully initialized. Enable error messages */
> > init_task.kasan_depth = 0;
> > - pr_info("KernelAddressSanitizer initialized.\n");
> > }
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index 93402a1d9c9..a324dcdb8eb 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -122,6 +122,7 @@ config PPC
> > # Please keep this list sorted alphabetically.
> > #
> > select ARCH_32BIT_OFF_T if PPC32
> > + select ARCH_DEFER_KASAN if KASAN && PPC_RADIX_MMU
> > select ARCH_DISABLE_KASAN_INLINE if PPC_RADIX_MMU
> > select ARCH_DMA_DEFAULT_COHERENT if !NOT_COHERENT_CACHE
> > select ARCH_ENABLE_MEMORY_HOTPLUG
> > diff --git a/arch/powerpc/include/asm/kasan.h
> > b/arch/powerpc/include/asm/kasan.h
> > index b5bbb94c51f..957a57c1db5 100644
> > --- a/arch/powerpc/include/asm/kasan.h
> > +++ b/arch/powerpc/include/asm/kasan.h
> > @@ -53,18 +53,6 @@
> > #endif
> >
> > #ifdef CONFIG_KASAN
> > -#ifdef CONFIG_PPC_BOOK3S_64
> > -DECLARE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key);
> > -
> > -static __always_inline bool kasan_arch_is_ready(void)
> > -{
> > - if (static_branch_likely(&powerpc_kasan_enabled_key))
> > - return true;
> > - return false;
> > -}
> > -
> > -#define kasan_arch_is_ready kasan_arch_is_ready
> > -#endif
> >
> > void kasan_early_init(void);
> > void kasan_mmu_init(void);
> > diff --git a/arch/powerpc/mm/kasan/init_32.c
> > b/arch/powerpc/mm/kasan/init_32.c
> > index 03666d790a5..1d083597464 100644
> > --- a/arch/powerpc/mm/kasan/init_32.c
> > +++ b/arch/powerpc/mm/kasan/init_32.c
> > @@ -165,7 +165,7 @@ void __init kasan_init(void)
> >
> > /* At this point kasan is fully initialized. Enable error messages */
> > init_task.kasan_depth = 0;
> > - pr_info("KASAN init done\n");
> > + kasan_init_generic();
> > }
> >
> > void __init kasan_late_init(void)
> > diff --git a/arch/powerpc/mm/kasan/init_book3e_64.c
> > b/arch/powerpc/mm/kasan/init_book3e_64.c
> > index 60c78aac0f6..0d3a73d6d4b 100644
> > --- a/arch/powerpc/mm/kasan/init_book3e_64.c
> > +++ b/arch/powerpc/mm/kasan/init_book3e_64.c
> > @@ -127,7 +127,7 @@ void __init kasan_init(void)
> >
> > /* Enable error messages */
> > init_task.kasan_depth = 0;
> > - pr_info("KASAN init done\n");
> > + kasan_init_generic();
> > }
> >
> > void __init kasan_late_init(void) { }
> > diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c
> > b/arch/powerpc/mm/kasan/init_book3s_64.c
> > index 7d959544c07..dcafa641804 100644
> > --- a/arch/powerpc/mm/kasan/init_book3s_64.c
> > +++ b/arch/powerpc/mm/kasan/init_book3s_64.c
> > @@ -19,8 +19,6 @@
> > #include <linux/memblock.h>
> > #include <asm/pgalloc.h>
> >
> > -DEFINE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key);
> > -
> > static void __init kasan_init_phys_region(void *start, void *end)
> > {
> > unsigned long k_start, k_end, k_cur;
> > @@ -92,11 +90,9 @@ void __init kasan_init(void)
> > */
> > memset(kasan_early_shadow_page, 0, PAGE_SIZE);
> >
> > - static_branch_inc(&powerpc_kasan_enabled_key);
> > -
> > /* Enable error messages */
> > init_task.kasan_depth = 0;
> > - pr_info("KASAN init done\n");
> > + kasan_init_generic();
> > }
> >
> > void __init kasan_early_init(void) { }
> > diff --git a/arch/um/Kconfig b/arch/um/Kconfig
> > index 9083bfdb773..a12cc072ab1 100644
> > --- a/arch/um/Kconfig
> > +++ b/arch/um/Kconfig
> > @@ -5,6 +5,7 @@ menu "UML-specific options"
> > config UML
> > bool
> > default y
> > + select ARCH_DEFER_KASAN if STATIC_LINK
>
> No need to also verify KASAN here like powerpc and loongarch ?
>
> > select ARCH_WANTS_DYNAMIC_TASK_STRUCT
> > select ARCH_HAS_CACHE_LINE_SIZE
> > select ARCH_HAS_CPU_FINALIZE_INIT
> > diff --git a/arch/um/include/asm/kasan.h b/arch/um/include/asm/kasan.h
> > index f97bb1f7b85..b54a4e937fd 100644
> > --- a/arch/um/include/asm/kasan.h
> > +++ b/arch/um/include/asm/kasan.h
> > @@ -24,10 +24,9 @@
> >
> > #ifdef CONFIG_KASAN
> > void kasan_init(void);
> > -extern int kasan_um_is_ready;
> >
> > -#ifdef CONFIG_STATIC_LINK
> > -#define kasan_arch_is_ready() (kasan_um_is_ready)
> > +#if defined(CONFIG_STATIC_LINK) && defined(CONFIG_KASAN_INLINE)
> > +#error UML does not work in KASAN_INLINE mode with STATIC_LINK enabled!
> > #endif
> > #else
> > static inline void kasan_init(void) { }
> > diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
> > index 76bec7de81b..261fdcd21be 100644
> > --- a/arch/um/kernel/mem.c
> > +++ b/arch/um/kernel/mem.c
> > @@ -21,9 +21,9 @@
> > #include <os.h>
> > #include <um_malloc.h>
> > #include <linux/sched/task.h>
> > +#include <linux/kasan.h>
> >
> > #ifdef CONFIG_KASAN
> > -int kasan_um_is_ready;
> > void kasan_init(void)
> > {
> > /*
> > @@ -32,7 +32,10 @@ void kasan_init(void)
> > */
> > kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE);
> > init_task.kasan_depth = 0;
> > - kasan_um_is_ready = true;
> > + /* Since kasan_init() is called before main(),
> > + * KASAN is initialized but the enablement is deferred after
> > + * jump_label_init(). See arch_mm_preinit().
> > + */
>
> Format standard is different outside network, see:
> https://docs.kernel.org/process/coding-style.html#commenting
>
> > }
> >
> > static void (*kasan_init_ptr)(void)
> > @@ -58,6 +61,9 @@ static unsigned long brk_end;
> >
> > void __init arch_mm_preinit(void)
> > {
> > + /* Safe to call after jump_label_init(). Enables KASAN. */
> > + kasan_init_generic();
> > +
> > /* clear the zero-page */
> > memset(empty_zero_page, 0, PAGE_SIZE);
> >
> > diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h
> > index 6f612d69ea0..9eca967d852 100644
> > --- a/include/linux/kasan-enabled.h
> > +++ b/include/linux/kasan-enabled.h
> > @@ -4,32 +4,46 @@
> >
> > #include <linux/static_key.h>
> >
> > -#ifdef CONFIG_KASAN_HW_TAGS
> > -
> > +#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS)
> > +/*
> > + * Global runtime flag for KASAN modes that need runtime control.
> > + * Used by ARCH_DEFER_KASAN architectures and HW_TAGS mode.
> > + */
> > DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled);
> >
> > +/*
> > + * Runtime control for shadow memory initialization or HW_TAGS mode.
> > + * Uses static key for architectures that need deferred KASAN or HW_TAGS.
> > + */
> > static __always_inline bool kasan_enabled(void)
> > {
> > return static_branch_likely(&kasan_flag_enabled);
> > }
> >
> > -static inline bool kasan_hw_tags_enabled(void)
> > +static inline void kasan_enable(void)
> > {
> > - return kasan_enabled();
> > + static_branch_enable(&kasan_flag_enabled);
> > }
> > -
> > -#else /* CONFIG_KASAN_HW_TAGS */
> > -
> > -static inline bool kasan_enabled(void)
> > +#else
> > +/* For architectures that can enable KASAN early, use compile-time check.
> > */
> > +static __always_inline bool kasan_enabled(void)
> > {
> > return IS_ENABLED(CONFIG_KASAN);
> > }
> >
> > +static inline void kasan_enable(void) {}
> > +#endif /* CONFIG_ARCH_DEFER_KASAN || CONFIG_KASAN_HW_TAGS */
> > +
> > +#ifdef CONFIG_KASAN_HW_TAGS
> > +static inline bool kasan_hw_tags_enabled(void)
> > +{
> > + return kasan_enabled();
> > +}
> > +#else
> > static inline bool kasan_hw_tags_enabled(void)
> > {
> > return false;
> > }
> > -
> > #endif /* CONFIG_KASAN_HW_TAGS */
> >
> > #endif /* LINUX_KASAN_ENABLED_H */
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index 890011071f2..51a8293d1af 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -543,6 +543,12 @@ void kasan_report_async(void);
> >
> > #endif /* CONFIG_KASAN_HW_TAGS */
> >
> > +#ifdef CONFIG_KASAN_GENERIC
> > +void __init kasan_init_generic(void);
> > +#else
> > +static inline void kasan_init_generic(void) { }
> > +#endif
> > +
> > #ifdef CONFIG_KASAN_SW_TAGS
> > void __init kasan_init_sw_tags(void);
> > #else
> > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> > index f82889a830f..38456560c85 100644
> > --- a/lib/Kconfig.kasan
> > +++ b/lib/Kconfig.kasan
> > @@ -19,6 +19,14 @@ config ARCH_DISABLE_KASAN_INLINE
> > Disables both inline and stack instrumentation. Selected by
> > architectures that do not support these instrumentation types.
> >
> > +config ARCH_DEFER_KASAN
> > + bool
> > + help
> > + Architectures should select this if they need to defer KASAN
> > + initialization until shadow memory is properly set up. This
> > + enables runtime control via static keys. Otherwise, KASAN uses
> > + compile-time constants for better performance.
> > +
> > config CC_HAS_KASAN_GENERIC
> > def_bool $(cc-option, -fsanitize=kernel-address)
> >
> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > index 9142964ab9c..d9d389870a2 100644
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -32,6 +32,15 @@
> > #include "kasan.h"
> > #include "../slab.h"
> >
> > +#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS)
> > +/*
> > + * Definition of the unified static key declared in kasan-enabled.h.
> > + * This provides consistent runtime enable/disable across KASAN modes.
> > + */
> > +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
> > +EXPORT_SYMBOL(kasan_flag_enabled);
>
> Shouldn't new exports be GPL ?
>
> > +#endif
> > +
> > struct slab *kasan_addr_to_slab(const void *addr)
> > {
> > if (virt_addr_valid(addr))
> > @@ -246,7 +255,7 @@ static inline void poison_slab_object(struct kmem_cache
> > *cache, void *object,
> > bool __kasan_slab_pre_free(struct kmem_cache *cache, void *object,
> > unsigned long ip)
> > {
> > - if (!kasan_arch_is_ready() || is_kfence_address(object))
> > + if (is_kfence_address(object))
>
> Here and below, no need to replace kasan_arch_is_ready() by
> kasan_enabled() ?
>
> > return false;
> > return check_slab_allocation(cache, object, ip);
> > }
> > @@ -254,7 +263,7 @@ bool __kasan_slab_pre_free(struct kmem_cache *cache,
> > void *object,
> > bool __kasan_slab_free(struct kmem_cache *cache, void *object, bool init,
> > bool still_accessible)
> > {
> > - if (!kasan_arch_is_ready() || is_kfence_address(object))
> > + if (is_kfence_address(object))
> > return false;
> >
> > /*
> > @@ -293,7 +302,7 @@ bool __kasan_slab_free(struct kmem_cache *cache, void
> > *object, bool init,
> >
> > static inline bool check_page_allocation(void *ptr, unsigned long ip)
> > {
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return false;
> >
> > if (ptr != page_address(virt_to_head_page(ptr))) {
> > @@ -522,7 +531,7 @@ bool __kasan_mempool_poison_object(void *ptr, unsigned
> > long ip)
> > return true;
> > }
> >
> > - if (is_kfence_address(ptr) || !kasan_arch_is_ready())
> > + if (is_kfence_address(ptr))
> > return true;
> >
> > slab = folio_slab(folio);
> > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> > index d54e89f8c3e..b413c46b3e0 100644
> > --- a/mm/kasan/generic.c
> > +++ b/mm/kasan/generic.c
> > @@ -36,6 +36,17 @@
> > #include "kasan.h"
> > #include "../slab.h"
> >
> > +/*
> > + * Initialize Generic KASAN and enable runtime checks.
> > + * This should be called from arch kasan_init() once shadow memory is
> > ready.
> > + */
> > +void __init kasan_init_generic(void)
> > +{
> > + kasan_enable();
> > +
> > + pr_info("KernelAddressSanitizer initialized (generic)\n");
> > +}
> > +
> > /*
> > * All functions below always inlined so compiler could
> > * perform better optimizations in each of __asan_loadX/__assn_storeX
> > @@ -165,7 +176,7 @@ static __always_inline bool check_region_inline(const
> > void *addr,
> > size_t size, bool write,
> > unsigned long ret_ip)
> > {
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return true;
> >
> > if (unlikely(size == 0))
> > @@ -193,7 +204,7 @@ bool kasan_byte_accessible(const void *addr)
> > {
> > s8 shadow_byte;
> >
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return true;
> >
> > shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
> > @@ -495,7 +506,7 @@ static void release_alloc_meta(struct kasan_alloc_meta
> > *meta)
> >
> > static void release_free_meta(const void *object, struct kasan_free_meta
> > *meta)
> > {
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return;
> >
> > /* Check if free meta is valid. */
> > @@ -562,7 +573,7 @@ void kasan_save_alloc_info(struct kmem_cache *cache,
> > void *object, gfp_t flags)
> > kasan_save_track(&alloc_meta->alloc_track, flags);
> > }
> >
> > -void kasan_save_free_info(struct kmem_cache *cache, void *object)
> > +void __kasan_save_free_info(struct kmem_cache *cache, void *object)
> > {
> > struct kasan_free_meta *free_meta;
> >
> > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> > index 9a6927394b5..c8289a3feab 100644
> > --- a/mm/kasan/hw_tags.c
> > +++ b/mm/kasan/hw_tags.c
> > @@ -45,13 +45,6 @@ static enum kasan_arg kasan_arg __ro_after_init;
> > static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
> > static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata;
> >
> > -/*
> > - * Whether KASAN is enabled at all.
> > - * The value remains false until KASAN is initialized by
> > kasan_init_hw_tags().
> > - */
> > -DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
> > -EXPORT_SYMBOL(kasan_flag_enabled);
> > -
> > /*
> > * Whether the selected mode is synchronous, asynchronous, or asymmetric.
> > * Defaults to KASAN_MODE_SYNC.
> > @@ -260,7 +253,7 @@ void __init kasan_init_hw_tags(void)
> > kasan_init_tags();
> >
> > /* KASAN is now initialized, enable it. */
> > - static_branch_enable(&kasan_flag_enabled);
> > + kasan_enable();
> >
> > pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s,
> > vmalloc=%s, stacktrace=%s)\n",
> > kasan_mode_info(),
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index 129178be5e6..8a9d8a6ea71 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -398,7 +398,13 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags,
> > depot_flags_t depot_flags);
> > void kasan_set_track(struct kasan_track *track, depot_stack_handle_t
> > stack);
> > void kasan_save_track(struct kasan_track *track, gfp_t flags);
> > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t
> > flags);
> > -void kasan_save_free_info(struct kmem_cache *cache, void *object);
> > +
> > +void __kasan_save_free_info(struct kmem_cache *cache, void *object);
> > +static inline void kasan_save_free_info(struct kmem_cache *cache, void
> > *object)
> > +{
> > + if (kasan_enabled())
> > + __kasan_save_free_info(cache, object);
> > +}
> >
> > #ifdef CONFIG_KASAN_GENERIC
> > bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
> > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
> > index d2c70cd2afb..2e126cb21b6 100644
> > --- a/mm/kasan/shadow.c
> > +++ b/mm/kasan/shadow.c
> > @@ -125,7 +125,7 @@ void kasan_poison(const void *addr, size_t size, u8
> > value, bool init)
> > {
> > void *shadow_start, *shadow_end;
> >
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return;
> >
> > /*
> > @@ -150,7 +150,7 @@ EXPORT_SYMBOL_GPL(kasan_poison);
> > #ifdef CONFIG_KASAN_GENERIC
> > void kasan_poison_last_granule(const void *addr, size_t size)
> > {
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return;
> >
> > if (size & KASAN_GRANULE_MASK) {
> > @@ -390,7 +390,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned
> > long size)
> > unsigned long shadow_start, shadow_end;
> > int ret;
> >
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return 0;
> >
> > if (!is_vmalloc_or_module_addr((void *)addr))
> > @@ -560,7 +560,7 @@ void kasan_release_vmalloc(unsigned long start,
> > unsigned long end,
> > unsigned long region_start, region_end;
> > unsigned long size;
> >
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return;
> >
> > region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
> > @@ -611,7 +611,7 @@ void *__kasan_unpoison_vmalloc(const void *start,
> > unsigned long size,
> > * with setting memory tags, so the KASAN_VMALLOC_INIT flag is
> > ignored.
> > */
> >
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return (void *)start;
> >
> > if (!is_vmalloc_or_module_addr(start))
> > @@ -636,7 +636,7 @@ void *__kasan_unpoison_vmalloc(const void *start,
> > unsigned long size,
> > */
> > void __kasan_poison_vmalloc(const void *start, unsigned long size)
> > {
> > - if (!kasan_arch_is_ready())
> > + if (!kasan_enabled())
> > return;
> >
> > if (!is_vmalloc_or_module_addr(start))
> > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> > index b9382b5b6a3..c75741a7460 100644
> > --- a/mm/kasan/sw_tags.c
> > +++ b/mm/kasan/sw_tags.c
> > @@ -44,6 +44,7 @@ void __init kasan_init_sw_tags(void)
> > per_cpu(prng_state, cpu) = (u32)get_cycles();
> >
> > kasan_init_tags();
> > + kasan_enable();
> >
> > pr_info("KernelAddressSanitizer initialized (sw-tags,
> > stacktrace=%s)\n",
> > str_on_off(kasan_stack_collection_enabled()));
> > diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
> > index d65d48b85f9..b9f31293622 100644
> > --- a/mm/kasan/tags.c
> > +++ b/mm/kasan/tags.c
> > @@ -142,7 +142,7 @@ void kasan_save_alloc_info(struct kmem_cache *cache,
> > void *object, gfp_t flags)
> > save_stack_info(cache, object, flags, false);
> > }
> >
> > -void kasan_save_free_info(struct kmem_cache *cache, void *object)
> > +void __kasan_save_free_info(struct kmem_cache *cache, void *object)
> > {
> > save_stack_info(cache, object, 0, true);
> > }
>
