arch/loongarch/mm/kasan_init.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2023 Loongson Technology Corporation Limited
  */
 #define pr_fmt(fmt) "kasan: " fmt
 #include <linux/kasan.h>
 #include <linux/memblock.h>
 #include <linux/sched/task.h>

 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
 #include <asm-generic/sections.h>

 static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);

 #ifdef __PAGETABLE_PUD_FOLDED
 #define __p4d_none(early, p4d) (0)
 #else
 #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \
 (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud)))
 #endif

 #ifdef __PAGETABLE_PMD_FOLDED
 #define __pud_none(early, pud) (0)
 #else
 #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \
 (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd)))
 #endif

 #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \
 (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte)))

 #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()) {
 		return (void *)(kasan_early_shadow_page);
 	} else {
 		unsigned long maddr = (unsigned long)addr;
 		unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
 		unsigned long offset = 0;

 		if (maddr >= FIXADDR_START)
 			return (void *)(kasan_early_shadow_page);

 		maddr &= XRANGE_SHADOW_MASK;
 		switch (xrange) {
 		case XKPRANGE_CC_SEG:
 			offset = XKPRANGE_CC_SHADOW_OFFSET;
 			break;
 		case XKPRANGE_UC_SEG:
 			offset = XKPRANGE_UC_SHADOW_OFFSET;
 			break;
 		case XKVRANGE_VC_SEG:
 			offset = XKVRANGE_VC_SHADOW_OFFSET;
 			break;
 		default:
 			WARN_ON(1);
 			return NULL;
 		}

 		return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset);
 	}
 }

 const void *kasan_shadow_to_mem(const void *shadow_addr)
 {
 	unsigned long addr = (unsigned long)shadow_addr;

 	if (unlikely(addr > KASAN_SHADOW_END) ||
 		unlikely(addr < KASAN_SHADOW_START)) {
 		WARN_ON(1);
 		return NULL;
 	}

 	if (addr >= XKVRANGE_VC_SHADOW_OFFSET)
 		return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START);
 	else if (addr >= XKPRANGE_UC_SHADOW_OFFSET)
 		return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START);
 	else if (addr >= XKPRANGE_CC_SHADOW_OFFSET)
 		return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START);
 	else {
 		WARN_ON(1);
 		return NULL;
 	}
 }

 /*
  * Alloc memory for shadow memory page table.
  */
 static phys_addr_t __init kasan_alloc_zeroed_page(int node)
 {
 	void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
 					__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
 	if (!p)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
 			__func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));

 	return __pa(p);
 }

 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early)
 {
 	if (__pmd_none(early, READ_ONCE(*pmdp))) {
 		phys_addr_t pte_phys = early ?
 				__pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
 		if (!early)
 			memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
 		pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
 	}

 	return pte_offset_kernel(pmdp, addr);
 }

 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early)
 {
 	if (__pud_none(early, READ_ONCE(*pudp))) {
 		phys_addr_t pmd_phys = early ?
 				__pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
 		if (!early)
 			memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
 		pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
 	}

 	return pmd_offset(pudp, addr);
 }

 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early)
 {
 	if (__p4d_none(early, READ_ONCE(*p4dp))) {
 		phys_addr_t pud_phys = early ?
 			__pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
 		if (!early)
 			memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
 		p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
 	}

 	return pud_offset(p4dp, addr);
 }

 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);

 	do {
 		phys_addr_t page_phys = early ?
 					__pa_symbol(kasan_early_shadow_page)
 					      : kasan_alloc_zeroed_page(node);
 		next = addr + PAGE_SIZE;
 		set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
 	} while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep)));
 }

 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);

 	do {
 		next = pmd_addr_end(addr, end);
 		kasan_pte_populate(pmdp, addr, next, node, early);
 	} while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp)));
 }

 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
 					    unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);

 	do {
 		next = pud_addr_end(addr, end);
 		kasan_pmd_populate(pudp, addr, next, node, early);
 	} while (pudp++, addr = next, addr != end);
 }

 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
 					    unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	p4d_t *p4dp = p4d_offset(pgdp, addr);

 	do {
 		next = p4d_addr_end(addr, end);
 		kasan_pud_populate(p4dp, addr, next, node, early);
 	} while (p4dp++, addr = next, addr != end);
 }

 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
 				      int node, bool early)
 {
 	unsigned long next;
 	pgd_t *pgdp;

 	pgdp = pgd_offset_k(addr);

 	do {
 		next = pgd_addr_end(addr, end);
 		kasan_p4d_populate(pgdp, addr, next, node, early);
 	} while (pgdp++, addr = next, addr != end);

 }

 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
 static void __init kasan_map_populate(unsigned long start, unsigned long end,
 				      int node)
 {
 	kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
 }

 asmlinkage void __init kasan_early_init(void)
 {
 	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
 	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
 }

 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
 {
 	WRITE_ONCE(*pgdp, pgdval);
 }

 static void __init clear_pgds(unsigned long start, unsigned long end)
 {
 	/*
 	 * Remove references to kasan page tables from
 	 * swapper_pg_dir. pgd_clear() can't be used
 	 * here because it's nop on 2,3-level pagetable setups
 	 */
 	for (; start < end; start += PGDIR_SIZE)
 		kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
 }

 void __init kasan_init(void)
 {
 	u64 i;
 	phys_addr_t pa_start, pa_end;

 	/*
 	 * PGD was populated as invalid_pmd_table or invalid_pud_table
 	 * in pagetable_init() which depends on how many levels of page
 	 * table you are using, but we had to clean the gpd of kasan
 	 * shadow memory, as the pgd value is none-zero.
 	 * The assertion pgd_none is going to be false and the formal populate
 	 * afterwards is not going to create any new pgd at all.
 	 */
 	memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
 	csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
 	local_flush_tlb_all();

 	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

 	/* Maps everything to a single page of zeroes */
 	kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);

 	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
 					kasan_mem_to_shadow((void *)KFENCE_AREA_END));

 	kasan_early_stage = false;

 	/* Populate the linear mapping */
 	for_each_mem_range(i, &pa_start, &pa_end) {
 		void *start = (void *)phys_to_virt(pa_start);
 		void *end   = (void *)phys_to_virt(pa_end);

 		if (start >= end)
 			break;

 		kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
 			(unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
 	}

 	/* Populate modules mapping */
 	kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
 		(unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
 	/*
 	 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
 	 * should make sure that it maps the zero page read-only.
 	 */
 	for (i = 0; i < PTRS_PER_PTE; i++)
 		set_pte(&kasan_early_shadow_pte[i],
 			pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));

 	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 	csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
 	local_flush_tlb_all();

 	/* At this point kasan is fully initialized. Enable error messages */
 	init_task.kasan_depth = 0;
 	pr_info("KernelAddressSanitizer initialized.\n");
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2023 Loongson Technology Corporation Limited
	*/
	#define pr_fmt(fmt) "kasan: " fmt
	#include <linux/kasan.h>
	#include <linux/memblock.h>
	#include <linux/sched/task.h>

	#include <asm/tlbflush.h>
	#include <asm/pgalloc.h>
	#include <asm-generic/sections.h>

	static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);

	#ifdef __PAGETABLE_PUD_FOLDED
	#define __p4d_none(early, p4d) (0)
	#else
	#define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \
	(__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud)))
	#endif

	#ifdef __PAGETABLE_PMD_FOLDED
	#define __pud_none(early, pud) (0)
	#else
	#define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \
	(__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd)))
	#endif

	#define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \
	(__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte)))

	#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()) {
	return (void *)(kasan_early_shadow_page);
	} else {
	unsigned long maddr = (unsigned long)addr;
	unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
	unsigned long offset = 0;

	if (maddr >= FIXADDR_START)
	return (void *)(kasan_early_shadow_page);

	maddr &= XRANGE_SHADOW_MASK;
	switch (xrange) {
	case XKPRANGE_CC_SEG:
	offset = XKPRANGE_CC_SHADOW_OFFSET;
	break;
	case XKPRANGE_UC_SEG:
	offset = XKPRANGE_UC_SHADOW_OFFSET;
	break;
	case XKVRANGE_VC_SEG:
	offset = XKVRANGE_VC_SHADOW_OFFSET;
	break;
	default:
	WARN_ON(1);
	return NULL;
	}

	return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset);
	}
	}

	const void kasan_shadow_to_mem(const void shadow_addr)
	{
	unsigned long addr = (unsigned long)shadow_addr;

	if (unlikely(addr > KASAN_SHADOW_END) \|\|
	unlikely(addr < KASAN_SHADOW_START)) {
	WARN_ON(1);
	return NULL;
	}

	if (addr >= XKVRANGE_VC_SHADOW_OFFSET)
	return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START);
	else if (addr >= XKPRANGE_UC_SHADOW_OFFSET)
	return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START);
	else if (addr >= XKPRANGE_CC_SHADOW_OFFSET)
	return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START);
	else {
	WARN_ON(1);
	return NULL;
	}
	}

	/*
	* Alloc memory for shadow memory page table.
	*/
	static phys_addr_t __init kasan_alloc_zeroed_page(int node)
	{
	void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
	__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
	if (!p)
	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
	__func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));

	return __pa(p);
	}

	static pte_t __init kasan_pte_offset(pmd_t pmdp, unsigned long addr, int node, bool early)
	{
	if (__pmd_none(early, READ_ONCE(*pmdp))) {
	phys_addr_t pte_phys = early ?
	__pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
	if (!early)
	memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
	pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
	}

	return pte_offset_kernel(pmdp, addr);
	}

	static pmd_t __init kasan_pmd_offset(pud_t pudp, unsigned long addr, int node, bool early)
	{
	if (__pud_none(early, READ_ONCE(*pudp))) {
	phys_addr_t pmd_phys = early ?
	__pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
	if (!early)
	memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
	pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
	}

	return pmd_offset(pudp, addr);
	}

	static pud_t __init kasan_pud_offset(p4d_t p4dp, unsigned long addr, int node, bool early)
	{
	if (__p4d_none(early, READ_ONCE(*p4dp))) {
	phys_addr_t pud_phys = early ?
	__pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
	if (!early)
	memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
	p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
	}

	return pud_offset(p4dp, addr);
	}

	static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);

	do {
	phys_addr_t page_phys = early ?
	__pa_symbol(kasan_early_shadow_page)
	: kasan_alloc_zeroed_page(node);
	next = addr + PAGE_SIZE;
	set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
	} while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep)));
	}

	static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);

	do {
	next = pmd_addr_end(addr, end);
	kasan_pte_populate(pmdp, addr, next, node, early);
	} while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp)));
	}

	static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);

	do {
	next = pud_addr_end(addr, end);
	kasan_pmd_populate(pudp, addr, next, node, early);
	} while (pudp++, addr = next, addr != end);
	}

	static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	p4d_t *p4dp = p4d_offset(pgdp, addr);

	do {
	next = p4d_addr_end(addr, end);
	kasan_pud_populate(p4dp, addr, next, node, early);
	} while (p4dp++, addr = next, addr != end);
	}

	static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
	int node, bool early)
	{
	unsigned long next;
	pgd_t *pgdp;

	pgdp = pgd_offset_k(addr);

	do {
	next = pgd_addr_end(addr, end);
	kasan_p4d_populate(pgdp, addr, next, node, early);
	} while (pgdp++, addr = next, addr != end);

	}

	/* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
	static void __init kasan_map_populate(unsigned long start, unsigned long end,
	int node)
	{
	kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
	}

	asmlinkage void __init kasan_early_init(void)
	{
	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
	}

	static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
	{
	WRITE_ONCE(*pgdp, pgdval);
	}

	static void __init clear_pgds(unsigned long start, unsigned long end)
	{
	/*
	* Remove references to kasan page tables from
	* swapper_pg_dir. pgd_clear() can't be used
	* here because it's nop on 2,3-level pagetable setups
	*/
	for (; start < end; start += PGDIR_SIZE)
	kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
	}

	void __init kasan_init(void)
	{
	u64 i;
	phys_addr_t pa_start, pa_end;

	/*
	* PGD was populated as invalid_pmd_table or invalid_pud_table
	* in pagetable_init() which depends on how many levels of page
	* table you are using, but we had to clean the gpd of kasan
	* shadow memory, as the pgd value is none-zero.
	* The assertion pgd_none is going to be false and the formal populate
	* afterwards is not going to create any new pgd at all.
	*/
	memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
	csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
	local_flush_tlb_all();

	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

	/* Maps everything to a single page of zeroes */
	kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);

	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
	kasan_mem_to_shadow((void *)KFENCE_AREA_END));

	kasan_early_stage = false;

	/* Populate the linear mapping */
	for_each_mem_range(i, &pa_start, &pa_end) {
	void start = (void )phys_to_virt(pa_start);
	void end = (void )phys_to_virt(pa_end);

	if (start >= end)
	break;

	kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
	(unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
	}

	/* Populate modules mapping */
	kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
	(unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
	/*
	* KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
	* should make sure that it maps the zero page read-only.
	*/
	for (i = 0; i < PTRS_PER_PTE; i++)
	set_pte(&kasan_early_shadow_pte[i],
	pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));

	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
	csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
	local_flush_tlb_all();

	/* At this point kasan is fully initialized. Enable error messages */
	init_task.kasan_depth = 0;
	pr_info("KernelAddressSanitizer initialized.\n");
	}