* + kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch added to mm-unstable branch
@ 2025-08-12 2:02 Andrew Morton
2025-08-18 6:00 ` Sabyrzhan Tasbolatov
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Morton @ 2025-08-12 2:02 UTC (permalink / raw)
To: mm-commits, zhangqing, vincenzo.frascino, ryabinin.a.a, hca,
glider, elver, dvyukov, davidgow, christophe.leroy, chenhuacai,
bhe, andreyknvl, alexghiti, alex, agordeev, snovitoll, akpm
The patch titled
Subject: kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
has been added to the -mm mm-unstable branch. Its filename is
kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Subject: kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
Date: Sun, 10 Aug 2025 17:57:45 +0500
Patch series "kasan: unify kasan_enabled() and remove arch-specific
implementations", v6.
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 patch (of 2):
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.
[1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN.
The core issue is that different architectures haveinconsistent 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 patch 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.
Let's replace kasan_arch_is_ready() with existing kasan_enabled() check,
which examines the static key being enabled if arch selects
ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch,
kasan_enabled() checks the enablement during compile time.
Now KASAN users can use a single kasan_enabled() check everywhere.
Link: https://lkml.kernel.org/r/20250810125746.1105476-1-snovitoll@gmail.com
Link: https://lkml.kernel.org/r/20250810125746.1105476-2-snovitoll@gmail.com
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: David Gow <davidgow@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Marco Elver <elver@google.com>
Cc: Qing Zhang <zhangqing@loongson.cn>
Cc: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
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 | 13 +++++++--
include/linux/kasan-enabled.h | 32 ++++++++++++++++-------
include/linux/kasan.h | 6 ++++
lib/Kconfig.kasan | 12 ++++++++
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, 106 insertions(+), 70 deletions(-)
--- a/arch/loongarch/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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 *ad
#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)
{
--- a/arch/loongarch/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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_NEEDS_DEFER_KASAN
select ARCH_DISABLE_KASAN_INLINE
select ARCH_ENABLE_MEMORY_HOTPLUG
select ARCH_ENABLE_MEMORY_HOTREMOVE
--- a/arch/loongarch/mm/kasan_init.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/arch/loongarch/mm/kasan_init.c
@@ -40,11 +40,9 @@ static pgd_t kasan_pg_dir[PTRS_PER_PGD]
#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");
}
--- a/arch/powerpc/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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);
--- a/arch/powerpc/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/arch/powerpc/Kconfig
@@ -122,6 +122,7 @@ config PPC
# Please keep this list sorted alphabetically.
#
select ARCH_32BIT_OFF_T if PPC32
+ select ARCH_NEEDS_DEFER_KASAN if 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
--- a/arch/powerpc/mm/kasan/init_32.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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)
--- a/arch/powerpc/mm/kasan/init_book3e_64.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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) { }
--- a/arch/powerpc/mm/kasan/init_book3s_64.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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) { }
--- a/arch/um/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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) { }
--- a/arch/um/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/arch/um/Kconfig
@@ -5,6 +5,7 @@ menu "UML-specific options"
config UML
bool
default y
+ select ARCH_NEEDS_DEFER_KASAN if STATIC_LINK
select ARCH_WANTS_DYNAMIC_TASK_STRUCT
select ARCH_HAS_CACHE_LINE_SIZE
select ARCH_HAS_CPU_FINALIZE_INIT
--- a/arch/um/kernel/mem.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/arch/um/kernel/mem.c
@@ -21,10 +21,10 @@
#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)
+void __init kasan_init(void)
{
/*
* kasan_map_memory will map all of the required address space and
@@ -32,7 +32,11 @@ 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().
+ */
}
static void (*kasan_init_ptr)(void)
@@ -58,6 +62,9 @@ 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);
--- a/include/linux/kasan-enabled.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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 */
--- a/include/linux/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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
--- a/lib/Kconfig.kasan~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/lib/Kconfig.kasan
@@ -19,6 +19,18 @@ config ARCH_DISABLE_KASAN_INLINE
Disables both inline and stack instrumentation. Selected by
architectures that do not support these instrumentation types.
+config ARCH_NEEDS_DEFER_KASAN
+ bool
+
+config ARCH_DEFER_KASAN
+ def_bool y
+ depends on KASAN && ARCH_NEEDS_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.
+
config CC_HAS_KASAN_GENERIC
def_bool $(cc-option, -fsanitize=kernel-address)
--- a/mm/kasan/common.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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_GPL(kasan_flag_enabled);
+#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(st
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))
return false;
return check_slab_allocation(cache, object, ip);
}
@@ -254,7 +263,7 @@ bool __kasan_slab_pre_free(struct kmem_c
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
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
return true;
}
- if (is_kfence_address(ptr) || !kasan_arch_is_ready())
+ if (is_kfence_address(ptr))
return true;
slab = folio_slab(folio);
--- a/mm/kasan/generic.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/mm/kasan/generic.c
@@ -37,6 +37,17 @@
#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
* depending on memory access size X.
@@ -165,7 +176,7 @@ static __always_inline bool check_region
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 *a
{
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 ka
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_c
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;
--- a/mm/kasan/hw_tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/mm/kasan/hw_tags.c
@@ -46,13 +46,6 @@ static enum kasan_arg_mode kasan_arg_mod
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(),
--- a/mm/kasan/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/mm/kasan/kasan.h
@@ -398,7 +398,13 @@ depot_stack_handle_t kasan_save_stack(gf
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);
--- a/mm/kasan/shadow.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/mm/kasan/shadow.c
@@ -125,7 +125,7 @@ void kasan_poison(const void *addr, size
{
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
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
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 voi
* 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 voi
*/
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))
--- a/mm/kasan/sw_tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/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()));
--- a/mm/kasan/tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
+++ a/mm/kasan/tags.c
@@ -142,7 +142,7 @@ void kasan_save_alloc_info(struct kmem_c
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);
}
_
Patches currently in -mm which might be from snovitoll@gmail.com are
kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
kasan-call-kasan_init_generic-in-kasan_init.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: + kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch added to mm-unstable branch
2025-08-12 2:02 + kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch added to mm-unstable branch Andrew Morton
@ 2025-08-18 6:00 ` Sabyrzhan Tasbolatov
0 siblings, 0 replies; 2+ messages in thread
From: Sabyrzhan Tasbolatov @ 2025-08-18 6:00 UTC (permalink / raw)
To: Andrew Morton; +Cc: mm-commits
On Tue, Aug 12, 2025 at 7:02 AM Andrew Morton <akpm@linux-foundation.org> wrote:
>
>
> The patch titled
> Subject: kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
> has been added to the -mm mm-unstable branch. Its filename is
> kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
>
> This patch will shortly appear at
> https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
>
> This patch will later appear in the mm-unstable branch at
> git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
>
Hello,
I can't seem to find my patches in mm-unstable (and in other branches
in your -mm repo).
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/log/?h=mm-unstable
I can see them in patches/old though, could you please advise if they
are not missed?
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/old/kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/old/kasan-call-kasan_init_generic-in-kasan_init.patch
Thanks!
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
> reply-to-all to that, adding suitable additional cc's
>
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
>
> The -mm tree is included into linux-next via the mm-everything
> branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> and is updated there every 2-3 working days
>
> ------------------------------------------------------
> From: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
> Subject: kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
> Date: Sun, 10 Aug 2025 17:57:45 +0500
>
> Patch series "kasan: unify kasan_enabled() and remove arch-specific
> implementations", v6.
>
> 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 patch (of 2):
>
> 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.
>
> [1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN.
>
> The core issue is that different architectures haveinconsistent 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 patch 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.
>
> Let's replace kasan_arch_is_ready() with existing kasan_enabled() check,
> which examines the static key being enabled if arch selects
> ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch,
> kasan_enabled() checks the enablement during compile time.
>
> Now KASAN users can use a single kasan_enabled() check everywhere.
>
> Link: https://lkml.kernel.org/r/20250810125746.1105476-1-snovitoll@gmail.com
> Link: https://lkml.kernel.org/r/20250810125746.1105476-2-snovitoll@gmail.com
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
> Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Cc: Alexander Gordeev <agordeev@linux.ibm.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Alexandre Ghiti <alex@ghiti.fr>
> Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: David Gow <davidgow@google.com>
> Cc: Dmitriy Vyukov <dvyukov@google.com>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Huacai Chen <chenhuacai@loongson.cn>
> Cc: Marco Elver <elver@google.com>
> Cc: Qing Zhang <zhangqing@loongson.cn>
> Cc: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> 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 | 13 +++++++--
> include/linux/kasan-enabled.h | 32 ++++++++++++++++-------
> include/linux/kasan.h | 6 ++++
> lib/Kconfig.kasan | 12 ++++++++
> 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, 106 insertions(+), 70 deletions(-)
>
> --- a/arch/loongarch/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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 *ad
> #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)
> {
> --- a/arch/loongarch/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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_NEEDS_DEFER_KASAN
> select ARCH_DISABLE_KASAN_INLINE
> select ARCH_ENABLE_MEMORY_HOTPLUG
> select ARCH_ENABLE_MEMORY_HOTREMOVE
> --- a/arch/loongarch/mm/kasan_init.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/arch/loongarch/mm/kasan_init.c
> @@ -40,11 +40,9 @@ static pgd_t kasan_pg_dir[PTRS_PER_PGD]
> #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");
> }
> --- a/arch/powerpc/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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);
> --- a/arch/powerpc/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/arch/powerpc/Kconfig
> @@ -122,6 +122,7 @@ config PPC
> # Please keep this list sorted alphabetically.
> #
> select ARCH_32BIT_OFF_T if PPC32
> + select ARCH_NEEDS_DEFER_KASAN if 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
> --- a/arch/powerpc/mm/kasan/init_32.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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)
> --- a/arch/powerpc/mm/kasan/init_book3e_64.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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) { }
> --- a/arch/powerpc/mm/kasan/init_book3s_64.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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) { }
> --- a/arch/um/include/asm/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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) { }
> --- a/arch/um/Kconfig~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/arch/um/Kconfig
> @@ -5,6 +5,7 @@ menu "UML-specific options"
> config UML
> bool
> default y
> + select ARCH_NEEDS_DEFER_KASAN if STATIC_LINK
> select ARCH_WANTS_DYNAMIC_TASK_STRUCT
> select ARCH_HAS_CACHE_LINE_SIZE
> select ARCH_HAS_CPU_FINALIZE_INIT
> --- a/arch/um/kernel/mem.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/arch/um/kernel/mem.c
> @@ -21,10 +21,10 @@
> #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)
> +void __init kasan_init(void)
> {
> /*
> * kasan_map_memory will map all of the required address space and
> @@ -32,7 +32,11 @@ 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().
> + */
> }
>
> static void (*kasan_init_ptr)(void)
> @@ -58,6 +62,9 @@ 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);
>
> --- a/include/linux/kasan-enabled.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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 */
> --- a/include/linux/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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
> --- a/lib/Kconfig.kasan~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/lib/Kconfig.kasan
> @@ -19,6 +19,18 @@ config ARCH_DISABLE_KASAN_INLINE
> Disables both inline and stack instrumentation. Selected by
> architectures that do not support these instrumentation types.
>
> +config ARCH_NEEDS_DEFER_KASAN
> + bool
> +
> +config ARCH_DEFER_KASAN
> + def_bool y
> + depends on KASAN && ARCH_NEEDS_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.
> +
> config CC_HAS_KASAN_GENERIC
> def_bool $(cc-option, -fsanitize=kernel-address)
>
> --- a/mm/kasan/common.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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_GPL(kasan_flag_enabled);
> +#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(st
> 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))
> return false;
> return check_slab_allocation(cache, object, ip);
> }
> @@ -254,7 +263,7 @@ bool __kasan_slab_pre_free(struct kmem_c
> 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
>
> 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
> return true;
> }
>
> - if (is_kfence_address(ptr) || !kasan_arch_is_ready())
> + if (is_kfence_address(ptr))
> return true;
>
> slab = folio_slab(folio);
> --- a/mm/kasan/generic.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/mm/kasan/generic.c
> @@ -37,6 +37,17 @@
> #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
> * depending on memory access size X.
> @@ -165,7 +176,7 @@ static __always_inline bool check_region
> 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 *a
> {
> 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 ka
>
> 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_c
> 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;
>
> --- a/mm/kasan/hw_tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/mm/kasan/hw_tags.c
> @@ -46,13 +46,6 @@ static enum kasan_arg_mode kasan_arg_mod
> 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(),
> --- a/mm/kasan/kasan.h~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/mm/kasan/kasan.h
> @@ -398,7 +398,13 @@ depot_stack_handle_t kasan_save_stack(gf
> 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);
> --- a/mm/kasan/shadow.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/mm/kasan/shadow.c
> @@ -125,7 +125,7 @@ void kasan_poison(const void *addr, size
> {
> 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
> 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
> 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 voi
> * 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 voi
> */
> 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))
> --- a/mm/kasan/sw_tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/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()));
> --- a/mm/kasan/tags.c~kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes
> +++ a/mm/kasan/tags.c
> @@ -142,7 +142,7 @@ void kasan_save_alloc_info(struct kmem_c
> 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);
> }
> _
>
> Patches currently in -mm which might be from snovitoll@gmail.com are
>
> kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch
> kasan-call-kasan_init_generic-in-kasan_init.patch
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-08-18 6:00 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-08-12 2:02 + kasan-introduce-arch_defer_kasan-and-unify-static-key-across-modes.patch added to mm-unstable branch Andrew Morton
2025-08-18 6:00 ` Sabyrzhan Tasbolatov
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.