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