mm/kasan/tags.c

Source file repositories/reference/linux-study-clean/mm/kasan/tags.c

File Facts

System
Linux kernel
Corpus path
mm/kasan/tags.c
Extension
.c
Size
3723 bytes
Lines
149
Domain
Core OS
Bucket
Memory Management
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * This file contains common tag-based KASAN code.
 *
 * Copyright (c) 2018 Google, Inc.
 * Copyright (c) 2020 Google, Inc.
 */

#include <linux/atomic.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/sched/clock.h>
#include <linux/stackdepot.h>
#include <linux/static_key.h>
#include <linux/string.h>
#include <linux/types.h>

#include "kasan.h"
#include "../slab.h"

#define KASAN_STACK_RING_SIZE_DEFAULT (32 << 10)

enum kasan_arg_stacktrace {
	KASAN_ARG_STACKTRACE_DEFAULT,
	KASAN_ARG_STACKTRACE_OFF,
	KASAN_ARG_STACKTRACE_ON,
};

static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata;

/* Whether to collect alloc/free stack traces. */
DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace);

/* Non-zero, as initial pointer values are 0. */
#define STACK_RING_BUSY_PTR ((void *)1)

struct kasan_stack_ring stack_ring = {
	.lock = __RW_LOCK_UNLOCKED(stack_ring.lock)
};

/* kasan.stacktrace=off/on */
static int __init early_kasan_flag_stacktrace(char *arg)
{
	if (!arg)
		return -EINVAL;

	if (!strcmp(arg, "off"))
		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF;
	else if (!strcmp(arg, "on"))
		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON;
	else
		return -EINVAL;

	return 0;
}
early_param("kasan.stacktrace", early_kasan_flag_stacktrace);

/* kasan.stack_ring_size=<number of entries> */
static int __init early_kasan_flag_stack_ring_size(char *arg)
{
	if (!arg)
		return -EINVAL;

	return kstrtoul(arg, 0, &stack_ring.size);
}
early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size);

void __init kasan_init_tags(void)
{
	switch (kasan_arg_stacktrace) {
	case KASAN_ARG_STACKTRACE_DEFAULT:
		/* Default is specified by kasan_flag_stacktrace definition. */
		break;
	case KASAN_ARG_STACKTRACE_OFF:
		static_branch_disable(&kasan_flag_stacktrace);
		break;
	case KASAN_ARG_STACKTRACE_ON:
		static_branch_enable(&kasan_flag_stacktrace);
		break;
	}

	if (kasan_stack_collection_enabled()) {
		if (!stack_ring.size)
			stack_ring.size = KASAN_STACK_RING_SIZE_DEFAULT;
		stack_ring.entries = memblock_alloc(
			sizeof(stack_ring.entries[0]) * stack_ring.size,

Annotation

Implementation Notes