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>
30 #define DEFAULT_COUNT 10
32 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
33 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
34 size_t count, loff_t *off);
35 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
36 size_t count, loff_t *off);
39 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
40 static ssize_t lkdtm_debugfs_entry(struct file *f,
41 const char __user *user_buf,
42 size_t count, loff_t *off);
43 # define CRASHPOINT_KPROBE(_symbol) \
45 .symbol_name = (_symbol), \
46 .pre_handler = lkdtm_kprobe_handler, \
48 # define CRASHPOINT_WRITE(_symbol) \
49 (_symbol) ? lkdtm_debugfs_entry : direct_entry
51 # define CRASHPOINT_KPROBE(_symbol)
52 # define CRASHPOINT_WRITE(_symbol) direct_entry
58 const struct file_operations fops;
62 #define CRASHPOINT(_name, _symbol) \
66 .read = lkdtm_debugfs_read, \
67 .llseek = generic_file_llseek, \
68 .open = lkdtm_debugfs_open, \
69 .write = CRASHPOINT_WRITE(_symbol) \
71 CRASHPOINT_KPROBE(_symbol) \
74 /* Define the possible places where we can trigger a crash point. */
75 static struct crashpoint crashpoints[] = {
76 CRASHPOINT("DIRECT", NULL),
78 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
79 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
80 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
81 CRASHPOINT("FS_DEVRW", "ll_rw_block"),
82 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
83 CRASHPOINT("TIMERADD", "hrtimer_start"),
84 CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"),
95 #define CRASHTYPE(_name) \
97 .name = __stringify(_name), \
98 .func = lkdtm_ ## _name, \
101 /* Define the possible types of crashes that can be triggered. */
102 static const struct crashtype crashtypes[] = {
106 CRASHTYPE(WARNING_MESSAGE),
107 CRASHTYPE(EXCEPTION),
109 CRASHTYPE(EXHAUST_STACK),
110 CRASHTYPE(CORRUPT_STACK),
111 CRASHTYPE(CORRUPT_STACK_STRONG),
112 CRASHTYPE(REPORT_STACK),
113 CRASHTYPE(CORRUPT_LIST_ADD),
114 CRASHTYPE(CORRUPT_LIST_DEL),
115 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
116 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
117 CRASHTYPE(UNSET_SMEP),
118 CRASHTYPE(CORRUPT_PAC),
119 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
120 CRASHTYPE(SLAB_LINEAR_OVERFLOW),
121 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
122 CRASHTYPE(WRITE_AFTER_FREE),
123 CRASHTYPE(READ_AFTER_FREE),
124 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
125 CRASHTYPE(READ_BUDDY_AFTER_FREE),
126 CRASHTYPE(SLAB_INIT_ON_ALLOC),
127 CRASHTYPE(BUDDY_INIT_ON_ALLOC),
128 CRASHTYPE(SLAB_FREE_DOUBLE),
129 CRASHTYPE(SLAB_FREE_CROSS),
130 CRASHTYPE(SLAB_FREE_PAGE),
131 CRASHTYPE(SOFTLOCKUP),
132 CRASHTYPE(HARDLOCKUP),
133 CRASHTYPE(SPINLOCKUP),
134 CRASHTYPE(HUNG_TASK),
135 CRASHTYPE(OVERFLOW_SIGNED),
136 CRASHTYPE(OVERFLOW_UNSIGNED),
137 CRASHTYPE(ARRAY_BOUNDS),
138 CRASHTYPE(EXEC_DATA),
139 CRASHTYPE(EXEC_STACK),
140 CRASHTYPE(EXEC_KMALLOC),
141 CRASHTYPE(EXEC_VMALLOC),
142 CRASHTYPE(EXEC_RODATA),
143 CRASHTYPE(EXEC_USERSPACE),
144 CRASHTYPE(EXEC_NULL),
145 CRASHTYPE(ACCESS_USERSPACE),
146 CRASHTYPE(ACCESS_NULL),
148 CRASHTYPE(WRITE_RO_AFTER_INIT),
149 CRASHTYPE(WRITE_KERN),
150 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
151 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
152 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
153 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
154 CRASHTYPE(REFCOUNT_DEC_ZERO),
155 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
156 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
157 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
158 CRASHTYPE(REFCOUNT_INC_ZERO),
159 CRASHTYPE(REFCOUNT_ADD_ZERO),
160 CRASHTYPE(REFCOUNT_INC_SATURATED),
161 CRASHTYPE(REFCOUNT_DEC_SATURATED),
162 CRASHTYPE(REFCOUNT_ADD_SATURATED),
163 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
164 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
165 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
166 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
167 CRASHTYPE(REFCOUNT_TIMING),
168 CRASHTYPE(ATOMIC_TIMING),
169 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
170 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
171 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
172 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
173 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
174 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
175 CRASHTYPE(USERCOPY_STACK_BEYOND),
176 CRASHTYPE(USERCOPY_KERNEL),
177 CRASHTYPE(STACKLEAK_ERASING),
178 CRASHTYPE(CFI_FORWARD_PROTO),
179 CRASHTYPE(FORTIFIED_OBJECT),
180 CRASHTYPE(FORTIFIED_SUBOBJECT),
181 CRASHTYPE(FORTIFIED_STRSCPY),
182 CRASHTYPE(DOUBLE_FAULT),
183 #ifdef CONFIG_PPC_BOOK3S_64
184 CRASHTYPE(PPC_SLB_MULTIHIT),
189 /* Global kprobe entry and crashtype. */
190 static struct kprobe *lkdtm_kprobe;
191 static struct crashpoint *lkdtm_crashpoint;
192 static const struct crashtype *lkdtm_crashtype;
194 /* Module parameters */
195 static int recur_count = -1;
196 module_param(recur_count, int, 0644);
197 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
199 static char* cpoint_name;
200 module_param(cpoint_name, charp, 0444);
201 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
203 static char* cpoint_type;
204 module_param(cpoint_type, charp, 0444);
205 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
206 "hitting the crash point");
208 static int cpoint_count = DEFAULT_COUNT;
209 module_param(cpoint_count, int, 0644);
210 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
211 "crash point is to be hit to trigger action");
214 /* Return the crashtype number or NULL if the name is invalid */
215 static const struct crashtype *find_crashtype(const char *name)
219 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
220 if (!strcmp(name, crashtypes[i].name))
221 return &crashtypes[i];
228 * This is forced noinline just so it distinctly shows up in the stackdump
229 * which makes validation of expected lkdtm crashes easier.
231 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
233 if (WARN_ON(!crashtype || !crashtype->func))
238 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
239 const struct crashtype *crashtype)
243 /* If this doesn't have a symbol, just call immediately. */
244 if (!crashpoint->kprobe.symbol_name) {
245 lkdtm_do_action(crashtype);
249 if (lkdtm_kprobe != NULL)
250 unregister_kprobe(lkdtm_kprobe);
252 lkdtm_crashpoint = crashpoint;
253 lkdtm_crashtype = crashtype;
254 lkdtm_kprobe = &crashpoint->kprobe;
255 ret = register_kprobe(lkdtm_kprobe);
257 pr_info("Couldn't register kprobe %s\n",
258 crashpoint->kprobe.symbol_name);
260 lkdtm_crashpoint = NULL;
261 lkdtm_crashtype = NULL;
267 #ifdef CONFIG_KPROBES
268 /* Global crash counter and spinlock. */
269 static int crash_count = DEFAULT_COUNT;
270 static DEFINE_SPINLOCK(crash_count_lock);
272 /* Called by kprobe entry points. */
273 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
278 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
281 spin_lock_irqsave(&crash_count_lock, flags);
283 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
284 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
286 if (crash_count == 0) {
288 crash_count = cpoint_count;
290 spin_unlock_irqrestore(&crash_count_lock, flags);
293 lkdtm_do_action(lkdtm_crashtype);
298 static ssize_t lkdtm_debugfs_entry(struct file *f,
299 const char __user *user_buf,
300 size_t count, loff_t *off)
302 struct crashpoint *crashpoint = file_inode(f)->i_private;
303 const struct crashtype *crashtype = NULL;
307 if (count >= PAGE_SIZE)
310 buf = (char *)__get_free_page(GFP_KERNEL);
313 if (copy_from_user(buf, user_buf, count)) {
314 free_page((unsigned long) buf);
317 /* NULL-terminate and remove enter */
321 crashtype = find_crashtype(buf);
322 free_page((unsigned long)buf);
327 err = lkdtm_register_cpoint(crashpoint, crashtype);
337 /* Generic read callback that just prints out the available crash types */
338 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
339 size_t count, loff_t *off)
344 buf = (char *)__get_free_page(GFP_KERNEL);
348 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
349 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
350 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
355 out = simple_read_from_buffer(user_buf, count, off,
357 free_page((unsigned long) buf);
362 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
367 /* Special entry to just crash directly. Available without KPROBEs */
368 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
369 size_t count, loff_t *off)
371 const struct crashtype *crashtype;
374 if (count >= PAGE_SIZE)
379 buf = (char *)__get_free_page(GFP_KERNEL);
382 if (copy_from_user(buf, user_buf, count)) {
383 free_page((unsigned long) buf);
386 /* NULL-terminate and remove enter */
390 crashtype = find_crashtype(buf);
391 free_page((unsigned long) buf);
395 pr_info("Performing direct entry %s\n", crashtype->name);
396 lkdtm_do_action(crashtype);
404 * To avoid needing to export parse_args(), just don't use this code
405 * when LKDTM is built as a module.
407 struct check_cmdline_args {
412 static int lkdtm_parse_one(char *param, char *val,
413 const char *unused, void *arg)
415 struct check_cmdline_args *args = arg;
417 /* short circuit if we already found a value. */
418 if (args->value != -ESRCH)
420 if (strncmp(param, args->param, strlen(args->param)) == 0) {
424 ret = kstrtobool(val, &bool_result);
426 args->value = bool_result;
431 int lkdtm_check_bool_cmdline(const char *param)
434 struct check_cmdline_args args = {
439 command_line = kstrdup(saved_command_line, GFP_KERNEL);
443 parse_args("Setting sysctl args", command_line,
444 NULL, 0, -1, -1, &args, lkdtm_parse_one);
452 static struct dentry *lkdtm_debugfs_root;
454 static int __init lkdtm_module_init(void)
456 struct crashpoint *crashpoint = NULL;
457 const struct crashtype *crashtype = NULL;
461 /* Neither or both of these need to be set */
462 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
463 pr_err("Need both cpoint_type and cpoint_name or neither\n");
468 crashtype = find_crashtype(cpoint_type);
470 pr_err("Unknown crashtype '%s'\n", cpoint_type);
476 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
477 if (!strcmp(cpoint_name, crashpoints[i].name))
478 crashpoint = &crashpoints[i];
481 /* Refuse unknown crashpoints. */
483 pr_err("Invalid crashpoint %s\n", cpoint_name);
488 #ifdef CONFIG_KPROBES
489 /* Set crash count. */
490 crash_count = cpoint_count;
493 /* Handle test-specific initialization. */
494 lkdtm_bugs_init(&recur_count);
496 lkdtm_usercopy_init();
499 /* Register debugfs interface */
500 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
502 /* Install debugfs trigger files. */
503 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
504 struct crashpoint *cur = &crashpoints[i];
506 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
510 /* Install crashpoint if one was selected. */
512 ret = lkdtm_register_cpoint(crashpoint, crashtype);
514 pr_info("Invalid crashpoint %s\n", crashpoint->name);
517 pr_info("Crash point %s of type %s registered\n",
518 crashpoint->name, cpoint_type);
520 pr_info("No crash points registered, enable through debugfs\n");
526 debugfs_remove_recursive(lkdtm_debugfs_root);
530 static void __exit lkdtm_module_exit(void)
532 debugfs_remove_recursive(lkdtm_debugfs_root);
534 /* Handle test-specific clean-up. */
536 lkdtm_usercopy_exit();
538 if (lkdtm_kprobe != NULL)
539 unregister_kprobe(lkdtm_kprobe);
541 pr_info("Crash point unregistered\n");
544 module_init(lkdtm_module_init);
545 module_exit(lkdtm_module_exit);
547 MODULE_LICENSE("GPL");
548 MODULE_DESCRIPTION("Kernel crash testing module");