1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Linux Kernel Dump Test Module for testing kernel crashes conditions:
4 * induces system failures at predefined crashpoints and under predefined
5 * operational conditions in order to evaluate the reliability of kernel
6 * sanity checking and crash dumps obtained using different dumping
9 * Copyright (C) IBM Corporation, 2006
11 * Author: Ankita Garg <ankita@in.ibm.com>
13 * It is adapted from the Linux Kernel Dump Test Tool by
14 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
16 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
18 * See Documentation/fault-injection/provoke-crashes.rst for instructions
22 #include <linux/module.h>
23 #include <linux/buffer_head.h>
24 #include <linux/kprobes.h>
25 #include <linux/list.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/debugfs.h>
29 #include <linux/init.h>
31 #define DEFAULT_COUNT 10
33 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
34 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
35 size_t count, loff_t *off);
36 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
37 size_t count, loff_t *off);
40 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
41 static ssize_t lkdtm_debugfs_entry(struct file *f,
42 const char __user *user_buf,
43 size_t count, loff_t *off);
44 # define CRASHPOINT_KPROBE(_symbol) \
46 .symbol_name = (_symbol), \
47 .pre_handler = lkdtm_kprobe_handler, \
49 # define CRASHPOINT_WRITE(_symbol) \
50 (_symbol) ? lkdtm_debugfs_entry : direct_entry
52 # define CRASHPOINT_KPROBE(_symbol)
53 # define CRASHPOINT_WRITE(_symbol) direct_entry
59 const struct file_operations fops;
63 #define CRASHPOINT(_name, _symbol) \
67 .read = lkdtm_debugfs_read, \
68 .llseek = generic_file_llseek, \
69 .open = lkdtm_debugfs_open, \
70 .write = CRASHPOINT_WRITE(_symbol) \
72 CRASHPOINT_KPROBE(_symbol) \
75 /* Define the possible places where we can trigger a crash point. */
76 static struct crashpoint crashpoints[] = {
77 CRASHPOINT("DIRECT", NULL),
79 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
80 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
81 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
82 CRASHPOINT("FS_DEVRW", "ll_rw_block"),
83 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
84 CRASHPOINT("TIMERADD", "hrtimer_start"),
85 CRASHPOINT("SCSI_DISPATCH_CMD", "scsi_dispatch_cmd"),
86 CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"),
97 #define CRASHTYPE(_name) \
99 .name = __stringify(_name), \
100 .func = lkdtm_ ## _name, \
103 /* Define the possible types of crashes that can be triggered. */
104 static const struct crashtype crashtypes[] = {
108 CRASHTYPE(WARNING_MESSAGE),
109 CRASHTYPE(EXCEPTION),
111 CRASHTYPE(EXHAUST_STACK),
112 CRASHTYPE(CORRUPT_STACK),
113 CRASHTYPE(CORRUPT_STACK_STRONG),
114 CRASHTYPE(REPORT_STACK),
115 CRASHTYPE(CORRUPT_LIST_ADD),
116 CRASHTYPE(CORRUPT_LIST_DEL),
117 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
118 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
119 CRASHTYPE(UNSET_SMEP),
120 CRASHTYPE(CORRUPT_PAC),
121 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
122 CRASHTYPE(FORTIFY_OBJECT),
123 CRASHTYPE(FORTIFY_SUBOBJECT),
124 CRASHTYPE(SLAB_LINEAR_OVERFLOW),
125 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
126 CRASHTYPE(WRITE_AFTER_FREE),
127 CRASHTYPE(READ_AFTER_FREE),
128 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
129 CRASHTYPE(READ_BUDDY_AFTER_FREE),
130 CRASHTYPE(SLAB_INIT_ON_ALLOC),
131 CRASHTYPE(BUDDY_INIT_ON_ALLOC),
132 CRASHTYPE(SLAB_FREE_DOUBLE),
133 CRASHTYPE(SLAB_FREE_CROSS),
134 CRASHTYPE(SLAB_FREE_PAGE),
135 CRASHTYPE(SOFTLOCKUP),
136 CRASHTYPE(HARDLOCKUP),
137 CRASHTYPE(SPINLOCKUP),
138 CRASHTYPE(HUNG_TASK),
139 CRASHTYPE(OVERFLOW_SIGNED),
140 CRASHTYPE(OVERFLOW_UNSIGNED),
141 CRASHTYPE(ARRAY_BOUNDS),
142 CRASHTYPE(EXEC_DATA),
143 CRASHTYPE(EXEC_STACK),
144 CRASHTYPE(EXEC_KMALLOC),
145 CRASHTYPE(EXEC_VMALLOC),
146 CRASHTYPE(EXEC_RODATA),
147 CRASHTYPE(EXEC_USERSPACE),
148 CRASHTYPE(EXEC_NULL),
149 CRASHTYPE(ACCESS_USERSPACE),
150 CRASHTYPE(ACCESS_NULL),
152 CRASHTYPE(WRITE_RO_AFTER_INIT),
153 CRASHTYPE(WRITE_KERN),
154 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
155 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
156 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
157 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
158 CRASHTYPE(REFCOUNT_DEC_ZERO),
159 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
160 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
161 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
162 CRASHTYPE(REFCOUNT_INC_ZERO),
163 CRASHTYPE(REFCOUNT_ADD_ZERO),
164 CRASHTYPE(REFCOUNT_INC_SATURATED),
165 CRASHTYPE(REFCOUNT_DEC_SATURATED),
166 CRASHTYPE(REFCOUNT_ADD_SATURATED),
167 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
168 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
169 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
170 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
171 CRASHTYPE(REFCOUNT_TIMING),
172 CRASHTYPE(ATOMIC_TIMING),
173 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
174 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
175 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
176 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
177 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
178 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
179 CRASHTYPE(USERCOPY_STACK_BEYOND),
180 CRASHTYPE(USERCOPY_KERNEL),
181 CRASHTYPE(STACKLEAK_ERASING),
182 CRASHTYPE(CFI_FORWARD_PROTO),
183 CRASHTYPE(FORTIFIED_STRSCPY),
184 CRASHTYPE(DOUBLE_FAULT),
185 #ifdef CONFIG_PPC_BOOK3S_64
186 CRASHTYPE(PPC_SLB_MULTIHIT),
191 /* Global kprobe entry and crashtype. */
192 static struct kprobe *lkdtm_kprobe;
193 static struct crashpoint *lkdtm_crashpoint;
194 static const struct crashtype *lkdtm_crashtype;
196 /* Module parameters */
197 static int recur_count = -1;
198 module_param(recur_count, int, 0644);
199 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
201 static char* cpoint_name;
202 module_param(cpoint_name, charp, 0444);
203 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
205 static char* cpoint_type;
206 module_param(cpoint_type, charp, 0444);
207 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
208 "hitting the crash point");
210 static int cpoint_count = DEFAULT_COUNT;
211 module_param(cpoint_count, int, 0644);
212 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
213 "crash point is to be hit to trigger action");
216 /* Return the crashtype number or NULL if the name is invalid */
217 static const struct crashtype *find_crashtype(const char *name)
221 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
222 if (!strcmp(name, crashtypes[i].name))
223 return &crashtypes[i];
230 * This is forced noinline just so it distinctly shows up in the stackdump
231 * which makes validation of expected lkdtm crashes easier.
233 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
235 if (WARN_ON(!crashtype || !crashtype->func))
240 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
241 const struct crashtype *crashtype)
245 /* If this doesn't have a symbol, just call immediately. */
246 if (!crashpoint->kprobe.symbol_name) {
247 lkdtm_do_action(crashtype);
251 if (lkdtm_kprobe != NULL)
252 unregister_kprobe(lkdtm_kprobe);
254 lkdtm_crashpoint = crashpoint;
255 lkdtm_crashtype = crashtype;
256 lkdtm_kprobe = &crashpoint->kprobe;
257 ret = register_kprobe(lkdtm_kprobe);
259 pr_info("Couldn't register kprobe %s\n",
260 crashpoint->kprobe.symbol_name);
262 lkdtm_crashpoint = NULL;
263 lkdtm_crashtype = NULL;
269 #ifdef CONFIG_KPROBES
270 /* Global crash counter and spinlock. */
271 static int crash_count = DEFAULT_COUNT;
272 static DEFINE_SPINLOCK(crash_count_lock);
274 /* Called by kprobe entry points. */
275 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
280 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
283 spin_lock_irqsave(&crash_count_lock, flags);
285 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
286 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
288 if (crash_count == 0) {
290 crash_count = cpoint_count;
292 spin_unlock_irqrestore(&crash_count_lock, flags);
295 lkdtm_do_action(lkdtm_crashtype);
300 static ssize_t lkdtm_debugfs_entry(struct file *f,
301 const char __user *user_buf,
302 size_t count, loff_t *off)
304 struct crashpoint *crashpoint = file_inode(f)->i_private;
305 const struct crashtype *crashtype = NULL;
309 if (count >= PAGE_SIZE)
312 buf = (char *)__get_free_page(GFP_KERNEL);
315 if (copy_from_user(buf, user_buf, count)) {
316 free_page((unsigned long) buf);
319 /* NULL-terminate and remove enter */
323 crashtype = find_crashtype(buf);
324 free_page((unsigned long)buf);
329 err = lkdtm_register_cpoint(crashpoint, crashtype);
339 /* Generic read callback that just prints out the available crash types */
340 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
341 size_t count, loff_t *off)
346 buf = (char *)__get_free_page(GFP_KERNEL);
350 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
351 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
352 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
357 out = simple_read_from_buffer(user_buf, count, off,
359 free_page((unsigned long) buf);
364 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
369 /* Special entry to just crash directly. Available without KPROBEs */
370 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
371 size_t count, loff_t *off)
373 const struct crashtype *crashtype;
376 if (count >= PAGE_SIZE)
381 buf = (char *)__get_free_page(GFP_KERNEL);
384 if (copy_from_user(buf, user_buf, count)) {
385 free_page((unsigned long) buf);
388 /* NULL-terminate and remove enter */
392 crashtype = find_crashtype(buf);
393 free_page((unsigned long) buf);
397 pr_info("Performing direct entry %s\n", crashtype->name);
398 lkdtm_do_action(crashtype);
406 * To avoid needing to export parse_args(), just don't use this code
407 * when LKDTM is built as a module.
409 struct check_cmdline_args {
414 static int lkdtm_parse_one(char *param, char *val,
415 const char *unused, void *arg)
417 struct check_cmdline_args *args = arg;
419 /* short circuit if we already found a value. */
420 if (args->value != -ESRCH)
422 if (strncmp(param, args->param, strlen(args->param)) == 0) {
426 ret = kstrtobool(val, &bool_result);
428 args->value = bool_result;
433 int lkdtm_check_bool_cmdline(const char *param)
436 struct check_cmdline_args args = {
441 command_line = kstrdup(saved_command_line, GFP_KERNEL);
445 parse_args("Setting sysctl args", command_line,
446 NULL, 0, -1, -1, &args, lkdtm_parse_one);
454 static struct dentry *lkdtm_debugfs_root;
456 static int __init lkdtm_module_init(void)
458 struct crashpoint *crashpoint = NULL;
459 const struct crashtype *crashtype = NULL;
463 /* Neither or both of these need to be set */
464 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
465 pr_err("Need both cpoint_type and cpoint_name or neither\n");
470 crashtype = find_crashtype(cpoint_type);
472 pr_err("Unknown crashtype '%s'\n", cpoint_type);
478 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
479 if (!strcmp(cpoint_name, crashpoints[i].name))
480 crashpoint = &crashpoints[i];
483 /* Refuse unknown crashpoints. */
485 pr_err("Invalid crashpoint %s\n", cpoint_name);
490 #ifdef CONFIG_KPROBES
491 /* Set crash count. */
492 crash_count = cpoint_count;
495 /* Handle test-specific initialization. */
496 lkdtm_bugs_init(&recur_count);
498 lkdtm_usercopy_init();
501 /* Register debugfs interface */
502 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
504 /* Install debugfs trigger files. */
505 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
506 struct crashpoint *cur = &crashpoints[i];
508 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
512 /* Install crashpoint if one was selected. */
514 ret = lkdtm_register_cpoint(crashpoint, crashtype);
516 pr_info("Invalid crashpoint %s\n", crashpoint->name);
519 pr_info("Crash point %s of type %s registered\n",
520 crashpoint->name, cpoint_type);
522 pr_info("No crash points registered, enable through debugfs\n");
528 debugfs_remove_recursive(lkdtm_debugfs_root);
532 static void __exit lkdtm_module_exit(void)
534 debugfs_remove_recursive(lkdtm_debugfs_root);
536 /* Handle test-specific clean-up. */
538 lkdtm_usercopy_exit();
540 if (lkdtm_kprobe != NULL)
541 unregister_kprobe(lkdtm_kprobe);
543 pr_info("Crash point unregistered\n");
546 module_init(lkdtm_module_init);
547 module_exit(lkdtm_module_exit);
549 MODULE_LICENSE("GPL");
550 MODULE_DESCRIPTION("Kernel crash testing module");