kmemcheck: rip it out

Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.comSigned-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/admin-guide/kernel-parameters.txt

@@ -1864,13 +1864,6 @@
 			Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
 			the default is off.
 
-	kmemcheck=	[X86] Boot-time kmemcheck enable/disable/one-shot mode
-			Valid arguments: 0, 1, 2
-			kmemcheck=0 (disabled)
-			kmemcheck=1 (enabled)
-			kmemcheck=2 (one-shot mode)
-			Default: 2 (one-shot mode)
-
 	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
 			Default is 0 (don't ignore, but inject #GP)
 

Documentation/dev-tools/index.rst

@@ -21,7 +21,6 @@ whole; patches welcome!
    kasan
    ubsan
    kmemleak
-   kmemcheck
    gdb-kernel-debugging
    kgdb
    kselftest

MAINTAINERS

@@ -7688,16 +7688,6 @@ F:	include/linux/kdb.h
 F:	include/linux/kgdb.h
 F:	kernel/debug/
 
-KMEMCHECK
-M:	Vegard Nossum <vegardno@ifi.uio.no>
-M:	Pekka Enberg <penberg@kernel.org>
-S:	Maintained
-F:	Documentation/dev-tools/kmemcheck.rst
-F:	arch/x86/include/asm/kmemcheck.h
-F:	arch/x86/mm/kmemcheck/
-F:	include/linux/kmemcheck.h
-F:	mm/kmemcheck.c
-
 KMEMLEAK
 M:	Catalin Marinas <catalin.marinas@arm.com>
 S:	Maintained

arch/x86/Kconfig

@@ -112,7 +112,6 @@ config X86
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_KASAN			if X86_64 && SPARSEMEM_VMEMMAP
 	select HAVE_ARCH_KGDB
-	select HAVE_ARCH_KMEMCHECK
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
@@ -1430,7 +1429,7 @@ config ARCH_DMA_ADDR_T_64BIT
 
 config X86_DIRECT_GBPAGES
 	def_bool y
-	depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
+	depends on X86_64 && !DEBUG_PAGEALLOC
 	---help---
 	  Certain kernel features effectively disable kernel
 	  linear 1 GB mappings (even if the CPU otherwise

arch/x86/include/asm/kmemcheck.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ASM_X86_KMEMCHECK_H
-#define ASM_X86_KMEMCHECK_H
-
-#include <linux/types.h>
-#include <asm/ptrace.h>
-
-#ifdef CONFIG_KMEMCHECK
-bool kmemcheck_active(struct pt_regs *regs);
-
-void kmemcheck_show(struct pt_regs *regs);
-void kmemcheck_hide(struct pt_regs *regs);
-
-bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code);
-bool kmemcheck_trap(struct pt_regs *regs);
-#else
-static inline bool kmemcheck_active(struct pt_regs *regs)
-{
-	return false;
-}
-
-static inline void kmemcheck_show(struct pt_regs *regs)
-{
-}
-
-static inline void kmemcheck_hide(struct pt_regs *regs)
-{
-}
-
-static inline bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code)
-{
-	return false;
-}
-
-static inline bool kmemcheck_trap(struct pt_regs *regs)
-{
-	return false;
-}
-#endif /* CONFIG_KMEMCHECK */
-
-#endif

arch/x86/include/asm/string_32.h

@@ -179,8 +179,6 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
  *	No 3D Now!
  */
 
-#ifndef CONFIG_KMEMCHECK
-
 #if (__GNUC__ >= 4)
 #define memcpy(t, f, n) __builtin_memcpy(t, f, n)
 #else
@@ -189,13 +187,6 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
 	 ? __constant_memcpy((t), (f), (n))	\
 	 : __memcpy((t), (f), (n)))
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(t, f, n) __memcpy((t), (f), (n))
-#endif
 
 #endif
 #endif /* !CONFIG_FORTIFY_SOURCE */

arch/x86/include/asm/string_64.h

@@ -33,7 +33,6 @@ extern void *memcpy(void *to, const void *from, size_t len);
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #ifndef CONFIG_FORTIFY_SOURCE
-#ifndef CONFIG_KMEMCHECK
 #if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
 #define memcpy(dst, src, len)					\
 ({								\
@@ -46,13 +45,6 @@ extern void *__memcpy(void *to, const void *from, size_t len);
 	__ret;							\
 })
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
-#endif
 #endif /* !CONFIG_FORTIFY_SOURCE */
 
 #define __HAVE_ARCH_MEMSET

arch/x86/kernel/cpu/intel.c

@@ -187,21 +187,6 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 	if (c->x86 == 6 && c->x86_model < 15)
 		clear_cpu_cap(c, X86_FEATURE_PAT);
 
-#ifdef CONFIG_KMEMCHECK
-	/*
-	 * P4s have a "fast strings" feature which causes single-
-	 * stepping REP instructions to only generate a #DB on
-	 * cache-line boundaries.
-	 *
-	 * Ingo Molnar reported a Pentium D (model 6) and a Xeon
-	 * (model 2) with the same problem.
-	 */
-	if (c->x86 == 15)
-		if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
-				  MSR_IA32_MISC_ENABLE_FAST_STRING_BIT) > 0)
-			pr_info("kmemcheck: Disabling fast string operations\n");
-#endif
-
 	/*
 	 * If fast string is not enabled in IA32_MISC_ENABLE for any reason,
 	 * clear the fast string and enhanced fast string CPU capabilities.

arch/x86/mm/Makefile

@@ -29,8 +29,6 @@ obj-$(CONFIG_X86_PTDUMP)	+= debug_pagetables.o
 
 obj-$(CONFIG_HIGHMEM)		+= highmem_32.o
 
-obj-$(CONFIG_KMEMCHECK)		+= kmemcheck/
-
 KASAN_SANITIZE_kasan_init_$(BITS).o := n
 obj-$(CONFIG_KASAN)		+= kasan_init_$(BITS).o
 

arch/x86/mm/init.c

@@ -163,12 +163,11 @@ static int page_size_mask;
 static void __init probe_page_size_mask(void)
 {
 	/*
-	 * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
-	 * use small pages.
+	 * For pagealloc debugging, identity mapping will use small pages.
 	 * This will simplify cpa(), which otherwise needs to support splitting
 	 * large pages into small in interrupt context, etc.
 	 */
-	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK))
+	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
 		page_size_mask |= 1 << PG_LEVEL_2M;
 	else
 		direct_gbpages = 0;

arch/x86/mm/kmemcheck/Makefile

-obj-y := error.o kmemcheck.o opcode.o pte.o selftest.o shadow.o

arch/x86/mm/kmemcheck/error.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/interrupt.h>
-#include <linux/kdebug.h>
-#include <linux/kmemcheck.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/stacktrace.h>
-#include <linux/string.h>
-
-#include "error.h"
-#include "shadow.h"
-
-enum kmemcheck_error_type {
-	KMEMCHECK_ERROR_INVALID_ACCESS,
-	KMEMCHECK_ERROR_BUG,
-};
-
-#define SHADOW_COPY_SIZE (1 << CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT)
-
-struct kmemcheck_error {
-	enum kmemcheck_error_type type;
-
-	union {
-		/* KMEMCHECK_ERROR_INVALID_ACCESS */
-		struct {
-			/* Kind of access that caused the error */
-			enum kmemcheck_shadow state;
-			/* Address and size of the erroneous read */
-			unsigned long	address;
-			unsigned int	size;
-		};
-	};
-
-	struct pt_regs		regs;
-	struct stack_trace	trace;
-	unsigned long		trace_entries[32];
-
-	/* We compress it to a char. */
-	unsigned char		shadow_copy[SHADOW_COPY_SIZE];
-	unsigned char		memory_copy[SHADOW_COPY_SIZE];
-};
-
-/*
- * Create a ring queue of errors to output. We can't call printk() directly
- * from the kmemcheck traps, since this may call the console drivers and
- * result in a recursive fault.
- */
-static struct kmemcheck_error error_fifo[CONFIG_KMEMCHECK_QUEUE_SIZE];
-static unsigned int error_count;
-static unsigned int error_rd;
-static unsigned int error_wr;
-static unsigned int error_missed_count;
-
-static struct kmemcheck_error *error_next_wr(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == ARRAY_SIZE(error_fifo)) {
-		++error_missed_count;
-		return NULL;
-	}
-
-	e = &error_fifo[error_wr];
-	if (++error_wr == ARRAY_SIZE(error_fifo))
-		error_wr = 0;
-	++error_count;
-	return e;
-}
-
-static struct kmemcheck_error *error_next_rd(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == 0)
-		return NULL;
-
-	e = &error_fifo[error_rd];
-	if (++error_rd == ARRAY_SIZE(error_fifo))
-		error_rd = 0;
-	--error_count;
-	return e;
-}
-
-void kmemcheck_error_recall(void)
-{
-	static const char *desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= "unallocated",
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= "uninitialized",
-		[KMEMCHECK_SHADOW_INITIALIZED]		= "initialized",
-		[KMEMCHECK_SHADOW_FREED]		= "freed",
-	};
-
-	static const char short_desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= 'a',
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= 'u',
-		[KMEMCHECK_SHADOW_INITIALIZED]		= 'i',
-		[KMEMCHECK_SHADOW_FREED]		= 'f',
-	};
-
-	struct kmemcheck_error *e;
-	unsigned int i;
-
-	e = error_next_rd();
-	if (!e)
-		return;
-
-	switch (e->type) {
-	case KMEMCHECK_ERROR_INVALID_ACCESS:
-		printk(KERN_WARNING "WARNING: kmemcheck: Caught %d-bit read from %s memory (%p)\n",
-			8 * e->size, e->state < ARRAY_SIZE(desc) ?
-				desc[e->state] : "(invalid shadow state)",
-			(void *) e->address);
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i)
-			printk(KERN_CONT "%02x", e->memory_copy[i]);
-		printk(KERN_CONT "\n");
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i) {
-			if (e->shadow_copy[i] < ARRAY_SIZE(short_desc))
-				printk(KERN_CONT " %c", short_desc[e->shadow_copy[i]]);
-			else
-				printk(KERN_CONT " ?");
-		}
-		printk(KERN_CONT "\n");
-		printk(KERN_WARNING "%*c\n", 2 + 2
-			* (int) (e->address & (SHADOW_COPY_SIZE - 1)), '^');
-		break;
-	case KMEMCHECK_ERROR_BUG:
-		printk(KERN_EMERG "ERROR: kmemcheck: Fatal error\n");
-		break;
-	}
-
-	__show_regs(&e->regs, 1);
-	print_stack_trace(&e->trace, 0);
-}
-
-static void do_wakeup(unsigned long data)
-{
-	while (error_count > 0)
-		kmemcheck_error_recall();
-
-	if (error_missed_count > 0) {
-		printk(KERN_WARNING "kmemcheck: Lost %d error reports because "
-			"the queue was too small\n", error_missed_count);
-		error_missed_count = 0;
-	}
-}
-
-static DECLARE_TASKLET(kmemcheck_tasklet, &do_wakeup, 0);
-
-/*
- * Save the context of an error report.
- */
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs)
-{
-	static unsigned long prev_ip;
-
-	struct kmemcheck_error *e;
-	void *shadow_copy;
-	void *memory_copy;
-
-	/* Don't report several adjacent errors from the same EIP. */
-	if (regs->ip == prev_ip)
-		return;
-	prev_ip = regs->ip;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_INVALID_ACCESS;
-
-	e->state = state;
-	e->address = address;
-	e->size = size;
-
-	/* Save regs */
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	/* Save stack trace */
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 0;
-	save_stack_trace_regs(regs, &e->trace);
-
-	/* Round address down to nearest 16 bytes */
-	shadow_copy = kmemcheck_shadow_lookup(address
-		& ~(SHADOW_COPY_SIZE - 1));
-	BUG_ON(!shadow_copy);
-
-	memcpy(e->shadow_copy, shadow_copy, SHADOW_COPY_SIZE);
-
-	kmemcheck_show_addr(address);
-	memory_copy = (void *) (address & ~(SHADOW_COPY_SIZE - 1));
-	memcpy(e->memory_copy, memory_copy, SHADOW_COPY_SIZE);
-	kmemcheck_hide_addr(address);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}
-
-/*
- * Save the context of a kmemcheck bug.
- */
-void kmemcheck_error_save_bug(struct pt_regs *regs)
-{
-	struct kmemcheck_error *e;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_BUG;
-
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 1;
-	save_stack_trace(&e->trace);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}

arch/x86/mm/kmemcheck/error.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__ERROR_H
-#define ARCH__X86__MM__KMEMCHECK__ERROR_H
-
-#include <linux/ptrace.h>
-
-#include "shadow.h"
-
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs);
-
-void kmemcheck_error_save_bug(struct pt_regs *regs);
-
-void kmemcheck_error_recall(void);
-
-#endif

arch/x86/mm/kmemcheck/opcode.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/types.h>
-
-#include "opcode.h"
-
-static bool opcode_is_prefix(uint8_t b)
-{
-	return
-		/* Group 1 */
-		b == 0xf0 || b == 0xf2 || b == 0xf3
-		/* Group 2 */
-		|| b == 0x2e || b == 0x36 || b == 0x3e || b == 0x26
-		|| b == 0x64 || b == 0x65
-		/* Group 3 */
-		|| b == 0x66
-		/* Group 4 */
-		|| b == 0x67;
-}
-
-#ifdef CONFIG_X86_64
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return (b & 0xf0) == 0x40;
-}
-#else
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return false;
-}
-#endif
-
-#define REX_W (1 << 3)
-
-/*
- * This is a VERY crude opcode decoder. We only need to find the size of the
- * load/store that caused our #PF and this should work for all the opcodes
- * that we care about. Moreover, the ones who invented this instruction set
- * should be shot.
- */
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size)
-{
-	/* Default operand size */
-	int operand_size_override = 4;
-
-	/* prefixes */
-	for (; opcode_is_prefix(*op); ++op) {
-		if (*op == 0x66)
-			operand_size_override = 2;
-	}
-
-	/* REX prefix */
-	if (opcode_is_rex_prefix(*op)) {
-		uint8_t rex = *op;
-
-		++op;
-		if (rex & REX_W) {
-			switch (*op) {
-			case 0x63:
-				*size = 4;
-				return;
-			case 0x0f:
-				++op;
-
-				switch (*op) {
-				case 0xb6:
-				case 0xbe:
-					*size = 1;
-					return;
-				case 0xb7:
-				case 0xbf:
-					*size = 2;
-					return;
-				}
-
-				break;
-			}
-
-			*size = 8;
-			return;
-		}
-	}
-
-	/* escape opcode */
-	if (*op == 0x0f) {
-		++op;
-
-		/*
-		 * This is move with zero-extend and sign-extend, respectively;
-		 * we don't have to think about 0xb6/0xbe, because this is
-		 * already handled in the conditional below.
-		 */
-		if (*op == 0xb7 || *op == 0xbf)
-			operand_size_override = 2;
-	}
-
-	*size = (*op & 1) ? operand_size_override : 1;
-}
-
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op)
-{
-	/* skip prefixes */
-	while (opcode_is_prefix(*op))
-		++op;
-	if (opcode_is_rex_prefix(*op))
-		++op;
-	return op;
-}

arch/x86/mm/kmemcheck/opcode.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__OPCODE_H
-#define ARCH__X86__MM__KMEMCHECK__OPCODE_H
-
-#include <linux/types.h>
-
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size);
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op);
-
-#endif

arch/x86/mm/kmemcheck/pte.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-#include "pte.h"
-
-pte_t *kmemcheck_pte_lookup(unsigned long address)
-{
-	pte_t *pte;
-	unsigned int level;
-
-	pte = lookup_address(address, &level);
-	if (!pte)
-		return NULL;
-	if (level != PG_LEVEL_4K)
-		return NULL;
-	if (!pte_hidden(*pte))
-		return NULL;
-
-	return pte;
-}
-

arch/x86/mm/kmemcheck/pte.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__PTE_H
-#define ARCH__X86__MM__KMEMCHECK__PTE_H
-
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-pte_t *kmemcheck_pte_lookup(unsigned long address);
-
-#endif

arch/x86/mm/kmemcheck/selftest.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/bug.h>
-#include <linux/kernel.h>
-
-#include "opcode.h"
-#include "selftest.h"
-
-struct selftest_opcode {
-	unsigned int expected_size;
-	const uint8_t *insn;
-	const char *desc;
-};
-
-static const struct selftest_opcode selftest_opcodes[] = {
-	/* REP MOVS */
-	{1, "\xf3\xa4", 		"rep movsb <mem8>, <mem8>"},
-	{4, "\xf3\xa5",			"rep movsl <mem32>, <mem32>"},
-
-	/* MOVZX / MOVZXD */
-	{1, "\x66\x0f\xb6\x51\xf8",	"movzwq <mem8>, <reg16>"},
-	{1, "\x0f\xb6\x51\xf8",		"movzwq <mem8>, <reg32>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x66\x0f\xbe\x51\xf8",	"movswq <mem8>, <reg16>"},
-	{1, "\x0f\xbe\x51\xf8",		"movswq <mem8>, <reg32>"},
-
-#ifdef CONFIG_X86_64
-	/* MOVZX / MOVZXD */
-	{1, "\x49\x0f\xb6\x51\xf8",	"movzbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xb7\x51\xf8",	"movzbq <mem16>, <reg64>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x49\x0f\xbe\x51\xf8",	"movsbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xbf\x51\xf8",	"movsbq <mem16>, <reg64>"},
-	{4, "\x49\x63\x51\xf8",		"movslq <mem32>, <reg64>"},
-#endif
-};
-
-static bool selftest_opcode_one(const struct selftest_opcode *op)
-{
-	unsigned size;
-
-	kmemcheck_opcode_decode(op->insn, &size);
-
-	if (size == op->expected_size)
-		return true;
-
-	printk(KERN_WARNING "kmemcheck: opcode %s: expected size %d, got %d\n",
-		op->desc, op->expected_size, size);
-	return false;
-}
-
-static bool selftest_opcodes_all(void)
-{
-	bool pass = true;
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(selftest_opcodes); ++i)
-		pass = pass && selftest_opcode_one(&selftest_opcodes[i]);
-
-	return pass;
-}
-
-bool kmemcheck_selftest(void)
-{
-	bool pass = true;
-
-	pass = pass && selftest_opcodes_all();
-
-	return pass;
-}

arch/x86/mm/kmemcheck/selftest.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH_X86_MM_KMEMCHECK_SELFTEST_H
-#define ARCH_X86_MM_KMEMCHECK_SELFTEST_H
-
-bool kmemcheck_selftest(void);
-
-#endif

arch/x86/mm/kmemcheck/shadow.c

-#include <linux/kmemcheck.h>
-#include <linux/export.h>
-#include <linux/mm.h>
-
-#include <asm/page.h>
-#include <asm/pgtable.h>
-
-#include "pte.h"
-#include "shadow.h"
-
-/*
- * Return the shadow address for the given address. Returns NULL if the
- * address is not tracked.
- *
- * We need to be extremely careful not to follow any invalid pointers,
- * because this function can be called for *any* possible address.
- */
-void *kmemcheck_shadow_lookup(unsigned long address)
-{
-	pte_t *pte;
-	struct page *page;
-
-	if (!virt_addr_valid(address))
-		return NULL;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return NULL;
-
-	page = virt_to_page(address);
-	if (!page->shadow)
-		return NULL;
-	return page->shadow + (address & (PAGE_SIZE - 1));
-}
-
-static void mark_shadow(void *address, unsigned int n,
-	enum kmemcheck_shadow status)
-{
-	unsigned long addr = (unsigned long) address;
-	unsigned long last_addr = addr + n - 1;
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long last_page = last_addr & PAGE_MASK;
-	unsigned int first_n;
-	void *shadow;
-
-	/* If the memory range crosses a page boundary, stop there. */
-	if (page == last_page)
-		first_n = n;
-	else
-		first_n = page + PAGE_SIZE - addr;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (shadow)
-		memset(shadow, status, first_n);
-
-	addr += first_n;
-	n -= first_n;
-
-	/* Do full-page memset()s. */
-	while (n >= PAGE_SIZE) {
-		shadow = kmemcheck_shadow_lookup(addr);
-		if (shadow)
-			memset(shadow, status, PAGE_SIZE);
-
-		addr += PAGE_SIZE;
-		n -= PAGE_SIZE;
-	}
-
-	/* Do the remaining page, if any. */
-	if (n > 0) {
-		shadow = kmemcheck_shadow_lookup(addr);
-		if (shadow)
-			memset(shadow, status, n);
-	}
-}
-
-void kmemcheck_mark_unallocated(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED);
-}
-
-void kmemcheck_mark_uninitialized(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED);
-}
-
-/*
- * Fill the shadow memory of the given address such that the memory at that
- * address is marked as being initialized.
- */
-void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED);
-}
-EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized);
-
-void kmemcheck_mark_freed(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_FREED);
-}
-
-void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE);
-}
-
-void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
-}
-
-void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE);
-}
-
-enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
-{
-#ifdef CONFIG_KMEMCHECK_PARTIAL_OK
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-
-	/*
-	 * Make sure _some_ bytes are initialized. Gcc frequently generates
-	 * code to access neighboring bytes.
-	 */
-	for (i = 0; i < size; ++i) {
-		if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)
-			return x[i];
-	}
-
-	return x[0];
-#else
-	return kmemcheck_shadow_test_all(shadow, size);
-#endif
-}
-
-enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size)
-{
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-
-	/* All bytes must be initialized. */
-	for (i = 0; i < size; ++i) {
-		if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)
-			return x[i];
-	}
-
-	return x[0];
-}
-
-void kmemcheck_shadow_set(void *shadow, unsigned int size)
-{
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-	for (i = 0; i < size; ++i)
-		x[i] = KMEMCHECK_SHADOW_INITIALIZED;
-}

arch/x86/mm/kmemcheck/shadow.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__SHADOW_H
-#define ARCH__X86__MM__KMEMCHECK__SHADOW_H
-
-enum kmemcheck_shadow {
-	KMEMCHECK_SHADOW_UNALLOCATED,
-	KMEMCHECK_SHADOW_UNINITIALIZED,
-	KMEMCHECK_SHADOW_INITIALIZED,
-	KMEMCHECK_SHADOW_FREED,
-};
-
-void *kmemcheck_shadow_lookup(unsigned long address);
-
-enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size);
-enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow,
-						unsigned int size);
-void kmemcheck_shadow_set(void *shadow, unsigned int size);
-
-#endif

include/linux/interrupt.h

@@ -594,21 +594,6 @@ static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 		__tasklet_hi_schedule(t);
 }
 
-extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
-
-/*
- * This version avoids touching any other tasklets. Needed for kmemcheck
- * in order not to take any page faults while enqueueing this tasklet;
- * consider VERY carefully whether you really need this or
- * tasklet_hi_schedule()...
- */
-static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
-{
-	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
-		__tasklet_hi_schedule_first(t);
-}
-
-
 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 {
 	atomic_inc(&t->count);

include/linux/kmemcheck.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef LINUX_KMEMCHECK_H
-#define LINUX_KMEMCHECK_H
-
-#include <linux/mm_types.h>
-#include <linux/types.h>
-
-#ifdef CONFIG_KMEMCHECK
-extern int kmemcheck_enabled;
-
-/* The slab-related functions. */
-void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node);
-void kmemcheck_free_shadow(struct page *page, int order);
-void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-			  size_t size);
-void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size);
-
-void kmemcheck_pagealloc_alloc(struct page *p, unsigned int order,
-			       gfp_t gfpflags);
-
-void kmemcheck_show_pages(struct page *p, unsigned int n);
-void kmemcheck_hide_pages(struct page *p, unsigned int n);
-
-bool kmemcheck_page_is_tracked(struct page *p);
-
-void kmemcheck_mark_unallocated(void *address, unsigned int n);
-void kmemcheck_mark_uninitialized(void *address, unsigned int n);
-void kmemcheck_mark_initialized(void *address, unsigned int n);
-void kmemcheck_mark_freed(void *address, unsigned int n);
-
-void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n);
-void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n);
-void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n);
-
-int kmemcheck_show_addr(unsigned long address);
-int kmemcheck_hide_addr(unsigned long address);
-
-bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size);
-
-/*
- * Bitfield annotations
- *
- * How to use: If you have a struct using bitfields, for example
- *
- *     struct a {
- *             int x:8, y:8;
- *     };
- *
- * then this should be rewritten as
- *
- *     struct a {
- *             kmemcheck_bitfield_begin(flags);
- *             int x:8, y:8;
- *             kmemcheck_bitfield_end(flags);
- *     };
- *
- * Now the "flags_begin" and "flags_end" members may be used to refer to the
- * beginning and end, respectively, of the bitfield (and things like
- * &x.flags_begin is allowed). As soon as the struct is allocated, the bit-
- * fields should be annotated:
- *
- *     struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL);
- *     kmemcheck_annotate_bitfield(a, flags);
- */
-#define kmemcheck_bitfield_begin(name)	\
-	int name##_begin[0];
-
-#define kmemcheck_bitfield_end(name)	\
-	int name##_end[0];
-
-#define kmemcheck_annotate_bitfield(ptr, name)				\
-	do {								\
-		int _n;							\
-									\
-		if (!ptr)						\
-			break;						\
-									\
-		_n = (long) &((ptr)->name##_end)			\
-			- (long) &((ptr)->name##_begin);		\
-		BUILD_BUG_ON(_n < 0);					\
-									\
-		kmemcheck_mark_initialized(&((ptr)->name##_begin), _n);	\
-	} while (0)
-
-#define kmemcheck_annotate_variable(var)				\
-	do {								\
-		kmemcheck_mark_initialized(&(var), sizeof(var));	\
-	} while (0)							\
-
-#else
-#define kmemcheck_enabled 0
-
-static inline void
-kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
-{
-}
-
-static inline void
-kmemcheck_free_shadow(struct page *page, int order)
-{
-}
-
-static inline void
-kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-		     size_t size)
-{
-}
-
-static inline void kmemcheck_slab_free(struct kmem_cache *s, void *object,
-				       size_t size)
-{
-}
-
-static inline void kmemcheck_pagealloc_alloc(struct page *p,
-	unsigned int order, gfp_t gfpflags)
-{
-}
-
-static inline bool kmemcheck_page_is_tracked(struct page *p)
-{
-	return false;
-}
-
-static inline void kmemcheck_mark_unallocated(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_uninitialized(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_freed(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_unallocated_pages(struct page *p,
-						    unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_uninitialized_pages(struct page *p,
-						      unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_initialized_pages(struct page *p,
-						    unsigned int n)
-{
-}
-
-static inline bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
-{
-	return true;
-}
-
-#define kmemcheck_bitfield_begin(name)
-#define kmemcheck_bitfield_end(name)
-#define kmemcheck_annotate_bitfield(ptr, name)	\
-	do {					\
-	} while (0)
-
-#define kmemcheck_annotate_variable(var)	\
-	do {					\
-	} while (0)
-
-#endif /* CONFIG_KMEMCHECK */
-
-#endif /* LINUX_KMEMCHECK_H */

kernel/softirq.c

@@ -486,16 +486,6 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
 }
 EXPORT_SYMBOL(__tasklet_hi_schedule);
 
-void __tasklet_hi_schedule_first(struct tasklet_struct *t)
-{
-	lockdep_assert_irqs_disabled();
-
-	t->next = __this_cpu_read(tasklet_hi_vec.head);
-	__this_cpu_write(tasklet_hi_vec.head, t);
-	__raise_softirq_irqoff(HI_SOFTIRQ);
-}
-EXPORT_SYMBOL(__tasklet_hi_schedule_first);
-
 static __latent_entropy void tasklet_action(struct softirq_action *a)
 {
 	struct tasklet_struct *list;

kernel/sysctl.c

@@ -30,7 +30,6 @@
 #include <linux/proc_fs.h>
 #include <linux/security.h>
 #include <linux/ctype.h>
-#include <linux/kmemcheck.h>
 #include <linux/kmemleak.h>
 #include <linux/fs.h>
 #include <linux/init.h>
@@ -1173,15 +1172,6 @@ static struct ctl_table kern_table[] = {
 		.extra1		= &zero,
 		.extra2		= &one_thousand,
 	},
-#endif
-#ifdef CONFIG_KMEMCHECK
-	{
-		.procname	= "kmemcheck",
-		.data		= &kmemcheck_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 #endif
 	{
 		.procname	= "panic_on_warn",

lib/Kconfig.debug

@@ -504,7 +504,7 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT
 
 config DEBUG_SLAB
 	bool "Debug slab memory allocations"
-	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
+	depends on DEBUG_KERNEL && SLAB
 	help
 	  Say Y here to have the kernel do limited verification on memory
 	  allocation as well as poisoning memory on free to catch use of freed
@@ -516,7 +516,7 @@ config DEBUG_SLAB_LEAK
 
 config SLUB_DEBUG_ON
 	bool "SLUB debugging on by default"
-	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
+	depends on SLUB && SLUB_DEBUG
 	default n
 	help
 	  Boot with debugging on by default. SLUB boots by default with
@@ -730,8 +730,6 @@ config DEBUG_STACKOVERFLOW
 
 	  If in doubt, say "N".
 
-source "lib/Kconfig.kmemcheck"
-
 source "lib/Kconfig.kasan"
 
 endmenu # "Memory Debugging"

lib/Kconfig.kmemcheck

-config HAVE_ARCH_KMEMCHECK
-	bool
-
-if HAVE_ARCH_KMEMCHECK
-
-menuconfig KMEMCHECK
-	bool "kmemcheck: trap use of uninitialized memory"
-	depends on DEBUG_KERNEL
-	depends on !X86_USE_3DNOW
-	depends on SLUB || SLAB
-	depends on !CC_OPTIMIZE_FOR_SIZE
-	depends on !FUNCTION_TRACER
-	select FRAME_POINTER
-	select STACKTRACE
-	default n
-	help
-	  This option enables tracing of dynamically allocated kernel memory
-	  to see if memory is used before it has been given an initial value.
-	  Be aware that this requires half of your memory for bookkeeping and
-	  will insert extra code at *every* read and write to tracked memory
-	  thus slow down the kernel code (but user code is unaffected).
-
-	  The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
-	  or enable kmemcheck at boot-time. If the kernel is started with
-	  kmemcheck=0, the large memory and CPU overhead is not incurred.
-
-choice
-	prompt "kmemcheck: default mode at boot"
-	depends on KMEMCHECK
-	default KMEMCHECK_ONESHOT_BY_DEFAULT
-	help
-	  This option controls the default behaviour of kmemcheck when the
-	  kernel boots and no kmemcheck= parameter is given.
-
-config KMEMCHECK_DISABLED_BY_DEFAULT
-	bool "disabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ENABLED_BY_DEFAULT
-	bool "enabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ONESHOT_BY_DEFAULT
-	bool "one-shot"
-	depends on KMEMCHECK
-	help
-	  In one-shot mode, only the first error detected is reported before
-	  kmemcheck is disabled.
-
-endchoice
-
-config KMEMCHECK_QUEUE_SIZE
-	int "kmemcheck: error queue size"
-	depends on KMEMCHECK
-	default 64
-	help
-	  Select the maximum number of errors to store in the queue. Since
-	  errors can occur virtually anywhere and in any context, we need a
-	  temporary storage area which is guarantueed not to generate any
-	  other faults. The queue will be emptied as soon as a tasklet may
-	  be scheduled. If the queue is full, new error reports will be
-	  lost.
-
-config KMEMCHECK_SHADOW_COPY_SHIFT
-	int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
-	depends on KMEMCHECK
-	range 2 8
-	default 5
-	help
-	  Select the number of shadow bytes to save along with each entry of
-	  the queue. These bytes indicate what parts of an allocation are
-	  initialized, uninitialized, etc. and will be displayed when an
-	  error is detected to help the debugging of a particular problem.
-
-config KMEMCHECK_PARTIAL_OK
-	bool "kmemcheck: allow partially uninitialized memory"
-	depends on KMEMCHECK
-	default y
-	help
-	  This option works around certain GCC optimizations that produce
-	  32-bit reads from 16-bit variables where the upper 16 bits are
-	  thrown away afterwards. This may of course also hide some real
-	  bugs.
-
-config KMEMCHECK_BITOPS_OK
-	bool "kmemcheck: allow bit-field manipulation"
-	depends on KMEMCHECK
-	default n
-	help
-	  This option silences warnings that would be generated for bit-field
-	  accesses where not all the bits are initialized at the same time.
-	  This may also hide some real bugs.
-
-endif

mm/Kconfig.debug

@@ -11,7 +11,6 @@ config DEBUG_PAGEALLOC
 	bool "Debug page memory allocations"
 	depends on DEBUG_KERNEL
 	depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
-	depends on !KMEMCHECK
 	select PAGE_EXTENSION
 	select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	---help---

mm/Makefile

@@ -17,7 +17,6 @@ KCOV_INSTRUMENT_slub.o := n
 KCOV_INSTRUMENT_page_alloc.o := n
 KCOV_INSTRUMENT_debug-pagealloc.o := n
 KCOV_INSTRUMENT_kmemleak.o := n
-KCOV_INSTRUMENT_kmemcheck.o := n
 KCOV_INSTRUMENT_memcontrol.o := n
 KCOV_INSTRUMENT_mmzone.o := n
 KCOV_INSTRUMENT_vmstat.o := n
@@ -70,7 +69,6 @@ obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += page_poison.o
 obj-$(CONFIG_SLAB) += slab.o
 obj-$(CONFIG_SLUB) += slub.o
-obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
 obj-$(CONFIG_KASAN)	+= kasan/
 obj-$(CONFIG_FAILSLAB) += failslab.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o

mm/kmemcheck.c

 // SPDX-License-Identifier: GPL-2.0
-#include <linux/gfp.h>
-#include <linux/mm_types.h>
-#include <linux/mm.h>
-#include <linux/slab.h>
-#include "slab.h"
-#include <linux/kmemcheck.h>
-
-void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
-{
-	struct page *shadow;
-	int pages;
-	int i;
-
-	pages = 1 << order;
-
-	/*
-	 * With kmemcheck enabled, we need to allocate a memory area for the
-	 * shadow bits as well.
-	 */
-	shadow = alloc_pages_node(node, flags, order);
-	if (!shadow) {
-		if (printk_ratelimit())
-			pr_err("kmemcheck: failed to allocate shadow bitmap\n");
-		return;
-	}
-
-	for(i = 0; i < pages; ++i)
-		page[i].shadow = page_address(&shadow[i]);
-
-	/*
-	 * Mark it as non-present for the MMU so that our accesses to
-	 * this memory will trigger a page fault and let us analyze
-	 * the memory accesses.
-	 */
-	kmemcheck_hide_pages(page, pages);
-}
-
-void kmemcheck_free_shadow(struct page *page, int order)
-{
-	struct page *shadow;
-	int pages;
-	int i;
-
-	if (!kmemcheck_page_is_tracked(page))
-		return;
-
-	pages = 1 << order;
-
-	kmemcheck_show_pages(page, pages);
-
-	shadow = virt_to_page(page[0].shadow);
-
-	for(i = 0; i < pages; ++i)
-		page[i].shadow = NULL;
-
-	__free_pages(shadow, order);
-}
-
-void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-			  size_t size)
-{
-	if (unlikely(!object)) /* Skip object if allocation failed */
-		return;
-
-	/*
-	 * Has already been memset(), which initializes the shadow for us
-	 * as well.
-	 */
-	if (gfpflags & __GFP_ZERO)
-		return;
-
-	/* No need to initialize the shadow of a non-tracked slab. */
-	if (s->flags & SLAB_NOTRACK)
-		return;
-
-	if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
-		/*
-		 * Allow notracked objects to be allocated from
-		 * tracked caches. Note however that these objects
-		 * will still get page faults on access, they just
-		 * won't ever be flagged as uninitialized. If page
-		 * faults are not acceptable, the slab cache itself
-		 * should be marked NOTRACK.
-		 */
-		kmemcheck_mark_initialized(object, size);
-	} else if (!s->ctor) {
-		/*
-		 * New objects should be marked uninitialized before
-		 * they're returned to the called.
-		 */
-		kmemcheck_mark_uninitialized(object, size);
-	}
-}
-
-void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
-{
-	/* TODO: RCU freeing is unsupported for now; hide false positives. */
-	if (!s->ctor && !(s->flags & SLAB_TYPESAFE_BY_RCU))
-		kmemcheck_mark_freed(object, size);
-}
-
-void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
-			       gfp_t gfpflags)
-{
-	int pages;
-
-	if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
-		return;
-
-	pages = 1 << order;
-
-	/*
-	 * NOTE: We choose to track GFP_ZERO pages too; in fact, they
-	 * can become uninitialized by copying uninitialized memory
-	 * into them.
-	 */
-
-	/* XXX: Can use zone->node for node? */
-	kmemcheck_alloc_shadow(page, order, gfpflags, -1);
-
-	if (gfpflags & __GFP_ZERO)
-		kmemcheck_mark_initialized_pages(page, pages);
-	else
-		kmemcheck_mark_uninitialized_pages(page, pages);
-}

mm/slub.c

@@ -1371,7 +1371,7 @@ static inline void *slab_free_hook(struct kmem_cache *s, void *x)
 	 * So in order to make the debug calls that expect irqs to be
 	 * disabled we need to disable interrupts temporarily.
 	 */
-#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
+#ifdef CONFIG_LOCKDEP
 	{
 		unsigned long flags;
 
@@ -1399,8 +1399,7 @@ static inline void slab_free_freelist_hook(struct kmem_cache *s,
  * Compiler cannot detect this function can be removed if slab_free_hook()
  * evaluates to nothing.  Thus, catch all relevant config debug options here.
  */
-#if defined(CONFIG_KMEMCHECK) ||		\
-	defined(CONFIG_LOCKDEP)	||		\
+#if defined(CONFIG_LOCKDEP)	||		\
 	defined(CONFIG_DEBUG_KMEMLEAK) ||	\
 	defined(CONFIG_DEBUG_OBJECTS_FREE) ||	\
 	defined(CONFIG_KASAN)

scripts/kernel-doc

@@ -2182,8 +2182,6 @@ sub dump_struct($$) {
 	# strip comments:
 	$members =~ s/\/\*.*?\*\///gos;
 	$nested =~ s/\/\*.*?\*\///gos;
-	# strip kmemcheck_bitfield_{begin,end}.*;
-	$members =~ s/kmemcheck_bitfield_.*?;//gos;
 	# strip attributes
 	$members =~ s/__attribute__\s*\(\([a-z,_\*\s\(\)]*\)\)//i;
 	$members =~ s/__aligned\s*\([^;]*\)//gos;

tools/include/linux/kmemcheck.h

 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LIBLOCKDEP_LINUX_KMEMCHECK_H_
-#define _LIBLOCKDEP_LINUX_KMEMCHECK_H_
-
-static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-}
-
-#endif