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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux Kernel Dump Test Module for testing kernel crashes conditions:
* induces system failures at predefined crashpoints and under predefined
* operational conditions in order to evaluate the reliability of kernel
* sanity checking and crash dumps obtained using different dumping
* solutions.
*
* Copyright (C) IBM Corporation, 2006
*
* Author: Ankita Garg <ankita@in.ibm.com>
*
* It is adapted from the Linux Kernel Dump Test Tool by
* Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
*
* Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
*
* See Documentation/fault-injection/provoke-crashes.rst for instructions
*/
#include "lkdtm.h"
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/kprobes.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#define DEFAULT_COUNT 10
static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
size_t count, loff_t *off);
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
size_t count, loff_t *off);
#ifdef CONFIG_KPROBES
static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
static ssize_t lkdtm_debugfs_entry(struct file *f,
const char __user *user_buf,
size_t count, loff_t *off);
# define CRASHPOINT_KPROBE(_symbol) \
.kprobe = { \
.symbol_name = (_symbol), \
.pre_handler = lkdtm_kprobe_handler, \
},
# define CRASHPOINT_WRITE(_symbol) \
(_symbol) ? lkdtm_debugfs_entry : direct_entry
#else
# define CRASHPOINT_KPROBE(_symbol)
# define CRASHPOINT_WRITE(_symbol) direct_entry
#endif
/* Crash points */
struct crashpoint {
const char *name;
const struct file_operations fops;
struct kprobe kprobe;
};
#define CRASHPOINT(_name, _symbol) \
{ \
.name = _name, \
.fops = { \
.read = lkdtm_debugfs_read, \
.llseek = generic_file_llseek, \
.open = lkdtm_debugfs_open, \
.write = CRASHPOINT_WRITE(_symbol) \
}, \
CRASHPOINT_KPROBE(_symbol) \
}
/* Define the possible places where we can trigger a crash point. */
static struct crashpoint crashpoints[] = {
CRASHPOINT("DIRECT", NULL),
#ifdef CONFIG_KPROBES
CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
CRASHPOINT("FS_DEVRW", "ll_rw_block"),
CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
CRASHPOINT("TIMERADD", "hrtimer_start"),
CRASHPOINT("SCSI_DISPATCH_CMD", "scsi_dispatch_cmd"),
CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"),
#endif
};
/* Crash types. */
struct crashtype {
const char *name;
void (*func)(void);
};
#define CRASHTYPE(_name) \
{ \
.name = __stringify(_name), \
.func = lkdtm_ ## _name, \
}
/* Define the possible types of crashes that can be triggered. */
static const struct crashtype crashtypes[] = {
CRASHTYPE(PANIC),
CRASHTYPE(BUG),
CRASHTYPE(WARNING),
CRASHTYPE(WARNING_MESSAGE),
CRASHTYPE(EXCEPTION),
CRASHTYPE(LOOP),
CRASHTYPE(EXHAUST_STACK),
CRASHTYPE(CORRUPT_STACK),
CRASHTYPE(CORRUPT_STACK_STRONG),
CRASHTYPE(CORRUPT_USER_DS),
CRASHTYPE(STACK_GUARD_PAGE_LEADING),
CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
CRASHTYPE(UNSET_SMEP),
CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
CRASHTYPE(OVERWRITE_ALLOCATION),
CRASHTYPE(WRITE_AFTER_FREE),
CRASHTYPE(READ_AFTER_FREE),
CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
CRASHTYPE(READ_BUDDY_AFTER_FREE),
CRASHTYPE(SLAB_FREE_DOUBLE),
CRASHTYPE(SLAB_FREE_CROSS),
CRASHTYPE(SLAB_FREE_PAGE),
CRASHTYPE(SOFTLOCKUP),
CRASHTYPE(HARDLOCKUP),
CRASHTYPE(SPINLOCKUP),
CRASHTYPE(HUNG_TASK),
CRASHTYPE(EXEC_DATA),
CRASHTYPE(EXEC_STACK),
CRASHTYPE(EXEC_KMALLOC),
CRASHTYPE(EXEC_VMALLOC),
CRASHTYPE(EXEC_RODATA),
CRASHTYPE(EXEC_USERSPACE),
CRASHTYPE(EXEC_NULL),
CRASHTYPE(ACCESS_USERSPACE),
CRASHTYPE(ACCESS_NULL),
CRASHTYPE(WRITE_RO),
CRASHTYPE(WRITE_RO_AFTER_INIT),
CRASHTYPE(WRITE_KERN),
CRASHTYPE(REFCOUNT_INC_OVERFLOW),
CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
CRASHTYPE(REFCOUNT_DEC_ZERO),
CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
CRASHTYPE(REFCOUNT_INC_ZERO),
CRASHTYPE(REFCOUNT_ADD_ZERO),
CRASHTYPE(REFCOUNT_INC_SATURATED),
CRASHTYPE(REFCOUNT_DEC_SATURATED),
CRASHTYPE(REFCOUNT_ADD_SATURATED),
CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
CRASHTYPE(REFCOUNT_TIMING),
CRASHTYPE(ATOMIC_TIMING),
CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
CRASHTYPE(USERCOPY_STACK_FRAME_TO),
CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
CRASHTYPE(USERCOPY_STACK_BEYOND),
CRASHTYPE(USERCOPY_KERNEL),
CRASHTYPE(USERCOPY_KERNEL_DS),
CRASHTYPE(STACKLEAK_ERASING),
CRASHTYPE(CFI_FORWARD_PROTO),
#ifdef CONFIG_X86_32
CRASHTYPE(DOUBLE_FAULT),
#endif
CRASHTYPE(LIST_ADD_NEXT_CORRUPTION),
CRASHTYPE(LIST_ADD_PREV_CORRUPTION),
CRASHTYPE(LIST_ADD_TWICE),
CRASHTYPE(LIST_DEL_NEXT_CORRUPTION),
CRASHTYPE(LIST_DEL_PREV_CORRUPTION),
CRASHTYPE(LIST_DEL_TWICE),
CRASHTYPE(HLIST_ADD_HEAD_CORRUPTION),
CRASHTYPE(HLIST_ADD_HEAD_TWICE),
CRASHTYPE(HLIST_ADD_BEFORE_CORRUPTION),
CRASHTYPE(HLIST_ADD_BEFORE_TWICE),
CRASHTYPE(HLIST_ADD_BEHIND_CORRUPTION),
CRASHTYPE(HLIST_ADD_BEHIND_TWICE),
CRASHTYPE(HLIST_DEL_PREV_CORRUPTION),
CRASHTYPE(HLIST_DEL_NEXT_CORRUPTION),
CRASHTYPE(HLIST_DEL_TWICE),
CRASHTYPE(HLIST_NULLS_ADD_HEAD_CORRUPTION),
CRASHTYPE(HLIST_NULLS_ADD_HEAD_TWICE),
CRASHTYPE(HLIST_NULLS_DEL_PREV_CORRUPTION),
CRASHTYPE(HLIST_NULLS_DEL_NEXT_CORRUPTION),
CRASHTYPE(HLIST_NULLS_DEL_TWICE),
CRASHTYPE(HLIST_BL_ADD_HEAD_UNLOCKED),
CRASHTYPE(HLIST_BL_ADD_HEAD_NODE_LOCKED),
CRASHTYPE(HLIST_BL_ADD_HEAD_CORRUPTION),
CRASHTYPE(HLIST_BL_ADD_HEAD_TWICE),
CRASHTYPE(HLIST_BL_DEL_NODE_LOCKED),
CRASHTYPE(HLIST_BL_DEL_NEXT_LOCKED),
CRASHTYPE(HLIST_BL_DEL_PREV_CORRUPTION),
CRASHTYPE(HLIST_BL_DEL_NEXT_CORRUPTION),
CRASHTYPE(HLIST_BL_DEL_TWICE),
};
/* Global kprobe entry and crashtype. */
static struct kprobe *lkdtm_kprobe;
static struct crashpoint *lkdtm_crashpoint;
static const struct crashtype *lkdtm_crashtype;
/* Module parameters */
static int recur_count = -1;
module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
static char* cpoint_name;
module_param(cpoint_name, charp, 0444);
MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
static char* cpoint_type;
module_param(cpoint_type, charp, 0444);
MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
"hitting the crash point");
static int cpoint_count = DEFAULT_COUNT;
module_param(cpoint_count, int, 0644);
MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
"crash point is to be hit to trigger action");
/* Return the crashtype number or NULL if the name is invalid */
static const struct crashtype *find_crashtype(const char *name)
{
int i;
for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
if (!strcmp(name, crashtypes[i].name))
return &crashtypes[i];
}
return NULL;
}
/*
* This is forced noinline just so it distinctly shows up in the stackdump
* which makes validation of expected lkdtm crashes easier.
*/
static noinline void lkdtm_do_action(const struct crashtype *crashtype)
{
if (WARN_ON(!crashtype || !crashtype->func))
return;
crashtype->func();
}
static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
const struct crashtype *crashtype)
{
int ret;
/* If this doesn't have a symbol, just call immediately. */
if (!crashpoint->kprobe.symbol_name) {
lkdtm_do_action(crashtype);
return 0;
}
if (lkdtm_kprobe != NULL)
unregister_kprobe(lkdtm_kprobe);
lkdtm_crashpoint = crashpoint;
lkdtm_crashtype = crashtype;
lkdtm_kprobe = &crashpoint->kprobe;
ret = register_kprobe(lkdtm_kprobe);
if (ret < 0) {
pr_info("Couldn't register kprobe %s\n",
crashpoint->kprobe.symbol_name);
lkdtm_kprobe = NULL;
lkdtm_crashpoint = NULL;
lkdtm_crashtype = NULL;
}
return ret;
}
#ifdef CONFIG_KPROBES
/* Global crash counter and spinlock. */
static int crash_count = DEFAULT_COUNT;
static DEFINE_SPINLOCK(crash_count_lock);
/* Called by kprobe entry points. */
static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
{
unsigned long flags;
bool do_it = false;
if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
return 0;
spin_lock_irqsave(&crash_count_lock, flags);
crash_count--;
pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
if (crash_count == 0) {
do_it = true;
crash_count = cpoint_count;
}
spin_unlock_irqrestore(&crash_count_lock, flags);
if (do_it)
lkdtm_do_action(lkdtm_crashtype);
return 0;
}
static ssize_t lkdtm_debugfs_entry(struct file *f,
const char __user *user_buf,
size_t count, loff_t *off)
{
struct crashpoint *crashpoint = file_inode(f)->i_private;
const struct crashtype *crashtype = NULL;
char *buf;
int err;
if (count >= PAGE_SIZE)
return -EINVAL;
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, user_buf, count)) {
free_page((unsigned long) buf);
return -EFAULT;
}
/* NULL-terminate and remove enter */
buf[count] = '\0';
strim(buf);
crashtype = find_crashtype(buf);
free_page((unsigned long)buf);
if (!crashtype)
return -EINVAL;
err = lkdtm_register_cpoint(crashpoint, crashtype);
if (err < 0)
return err;
*off += count;
return count;
}
#endif
/* Generic read callback that just prints out the available crash types */
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
size_t count, loff_t *off)
{
char *buf;
int i, n, out;
buf = (char *)__get_free_page(GFP_KERNEL);
if (buf == NULL)
return -ENOMEM;
n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
crashtypes[i].name);
}
buf[n] = '\0';
out = simple_read_from_buffer(user_buf, count, off,
buf, n);
free_page((unsigned long) buf);
return out;
}
static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
{
return 0;
}
/* Special entry to just crash directly. Available without KPROBEs */
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
size_t count, loff_t *off)
{
const struct crashtype *crashtype;
char *buf;
if (count >= PAGE_SIZE)
return -EINVAL;
if (count < 1)
return -EINVAL;
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, user_buf, count)) {
free_page((unsigned long) buf);
return -EFAULT;
}
/* NULL-terminate and remove enter */
buf[count] = '\0';
strim(buf);
crashtype = find_crashtype(buf);
free_page((unsigned long) buf);
if (!crashtype)
return -EINVAL;
pr_info("Performing direct entry %s\n", crashtype->name);
lkdtm_do_action(crashtype);
*off += count;
return count;
}
static struct dentry *lkdtm_debugfs_root;
static int __init lkdtm_module_init(void)
{
struct crashpoint *crashpoint = NULL;
const struct crashtype *crashtype = NULL;
int ret;
int i;
/* Neither or both of these need to be set */
if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
pr_err("Need both cpoint_type and cpoint_name or neither\n");
return -EINVAL;
}
if (cpoint_type) {
crashtype = find_crashtype(cpoint_type);
if (!crashtype) {
pr_err("Unknown crashtype '%s'\n", cpoint_type);
return -EINVAL;
}
}
if (cpoint_name) {
for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
if (!strcmp(cpoint_name, crashpoints[i].name))
crashpoint = &crashpoints[i];
}
/* Refuse unknown crashpoints. */
if (!crashpoint) {
pr_err("Invalid crashpoint %s\n", cpoint_name);
return -EINVAL;
}
}
#ifdef CONFIG_KPROBES
/* Set crash count. */
crash_count = cpoint_count;
#endif
/* Handle test-specific initialization. */
lkdtm_bugs_init(&recur_count);
lkdtm_perms_init();
lkdtm_usercopy_init();
lkdtm_heap_init();
/* Register debugfs interface */
lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
/* Install debugfs trigger files. */
for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
struct crashpoint *cur = &crashpoints[i];
debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
&cur->fops);
}
/* Install crashpoint if one was selected. */
if (crashpoint) {
ret = lkdtm_register_cpoint(crashpoint, crashtype);
if (ret < 0) {
pr_info("Invalid crashpoint %s\n", crashpoint->name);
goto out_err;
}
pr_info("Crash point %s of type %s registered\n",
crashpoint->name, cpoint_type);
} else {
pr_info("No crash points registered, enable through debugfs\n");
}
return 0;
out_err:
debugfs_remove_recursive(lkdtm_debugfs_root);
return ret;
}
static void __exit lkdtm_module_exit(void)
{
debugfs_remove_recursive(lkdtm_debugfs_root);
/* Handle test-specific clean-up. */
lkdtm_heap_exit();
lkdtm_usercopy_exit();
if (lkdtm_kprobe != NULL)
unregister_kprobe(lkdtm_kprobe);
pr_info("Crash point unregistered\n");
}
module_init(lkdtm_module_init);
module_exit(lkdtm_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kernel crash testing module");