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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
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
7 * solutions.
8 *
9 * Copyright (C) IBM Corporation, 2006
10 *
11 * Author: Ankita Garg <ankita@in.ibm.com>
12 *
13 * It is adapted from the Linux Kernel Dump Test Tool by
14 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
15 *
16 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
17 *
18 * See Documentation/fault-injection/provoke-crashes.rst for instructions
19 */
20#include "lkdtm.h"
21#include <linux/fs.h>
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
30#define DEFAULT_COUNT 10
31
32static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
33static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
34 size_t count, loff_t *off);
35static ssize_t direct_entry(struct file *f, const char __user *user_buf,
36 size_t count, loff_t *off);
37
38#ifdef CONFIG_KPROBES
39static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
40static 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) \
44 .kprobe = { \
45 .symbol_name = (_symbol), \
46 .pre_handler = lkdtm_kprobe_handler, \
47 },
48# define CRASHPOINT_WRITE(_symbol) \
49 (_symbol) ? lkdtm_debugfs_entry : direct_entry
50#else
51# define CRASHPOINT_KPROBE(_symbol)
52# define CRASHPOINT_WRITE(_symbol) direct_entry
53#endif
54
55/* Crash points */
56struct crashpoint {
57 const char *name;
58 const struct file_operations fops;
59 struct kprobe kprobe;
60};
61
62#define CRASHPOINT(_name, _symbol) \
63 { \
64 .name = _name, \
65 .fops = { \
66 .read = lkdtm_debugfs_read, \
67 .llseek = generic_file_llseek, \
68 .open = lkdtm_debugfs_open, \
69 .write = CRASHPOINT_WRITE(_symbol) \
70 }, \
71 CRASHPOINT_KPROBE(_symbol) \
72 }
73
74/* Define the possible places where we can trigger a crash point. */
75static struct crashpoint crashpoints[] = {
76 CRASHPOINT("DIRECT", NULL),
77#ifdef CONFIG_KPROBES
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_DISPATCH_CMD", "scsi_dispatch_cmd"),
85 CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"),
86#endif
87};
88
89
90/* Crash types. */
91struct crashtype {
92 const char *name;
93 void (*func)(void);
94};
95
96#define CRASHTYPE(_name) \
97 { \
98 .name = __stringify(_name), \
99 .func = lkdtm_ ## _name, \
100 }
101
102/* Define the possible types of crashes that can be triggered. */
103static const struct crashtype crashtypes[] = {
104 CRASHTYPE(PANIC),
105 CRASHTYPE(BUG),
106 CRASHTYPE(WARNING),
107 CRASHTYPE(WARNING_MESSAGE),
108 CRASHTYPE(EXCEPTION),
109 CRASHTYPE(LOOP),
110 CRASHTYPE(EXHAUST_STACK),
111 CRASHTYPE(CORRUPT_STACK),
112 CRASHTYPE(CORRUPT_STACK_STRONG),
113 CRASHTYPE(CORRUPT_LIST_ADD),
114 CRASHTYPE(CORRUPT_LIST_DEL),
115 CRASHTYPE(CORRUPT_USER_DS),
116 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
117 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
118 CRASHTYPE(UNSET_SMEP),
119 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
120 CRASHTYPE(OVERWRITE_ALLOCATION),
121 CRASHTYPE(WRITE_AFTER_FREE),
122 CRASHTYPE(READ_AFTER_FREE),
123 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
124 CRASHTYPE(READ_BUDDY_AFTER_FREE),
125 CRASHTYPE(SLAB_FREE_DOUBLE),
126 CRASHTYPE(SLAB_FREE_CROSS),
127 CRASHTYPE(SLAB_FREE_PAGE),
128 CRASHTYPE(SOFTLOCKUP),
129 CRASHTYPE(HARDLOCKUP),
130 CRASHTYPE(SPINLOCKUP),
131 CRASHTYPE(HUNG_TASK),
132 CRASHTYPE(EXEC_DATA),
133 CRASHTYPE(EXEC_STACK),
134 CRASHTYPE(EXEC_KMALLOC),
135 CRASHTYPE(EXEC_VMALLOC),
136 CRASHTYPE(EXEC_RODATA),
137 CRASHTYPE(EXEC_USERSPACE),
138 CRASHTYPE(EXEC_NULL),
139 CRASHTYPE(ACCESS_USERSPACE),
140 CRASHTYPE(ACCESS_NULL),
141 CRASHTYPE(WRITE_RO),
142 CRASHTYPE(WRITE_RO_AFTER_INIT),
143 CRASHTYPE(WRITE_KERN),
144 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
145 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
146 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
147 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
148 CRASHTYPE(REFCOUNT_DEC_ZERO),
149 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
150 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
151 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
152 CRASHTYPE(REFCOUNT_INC_ZERO),
153 CRASHTYPE(REFCOUNT_ADD_ZERO),
154 CRASHTYPE(REFCOUNT_INC_SATURATED),
155 CRASHTYPE(REFCOUNT_DEC_SATURATED),
156 CRASHTYPE(REFCOUNT_ADD_SATURATED),
157 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
158 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
159 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
160 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
161 CRASHTYPE(REFCOUNT_TIMING),
162 CRASHTYPE(ATOMIC_TIMING),
163 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
164 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
165 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
166 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
167 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
168 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
169 CRASHTYPE(USERCOPY_STACK_BEYOND),
170 CRASHTYPE(USERCOPY_KERNEL),
171 CRASHTYPE(USERCOPY_KERNEL_DS),
172 CRASHTYPE(STACKLEAK_ERASING),
173 CRASHTYPE(CFI_FORWARD_PROTO),
174};
175
176
177/* Global kprobe entry and crashtype. */
178static struct kprobe *lkdtm_kprobe;
179static struct crashpoint *lkdtm_crashpoint;
180static const struct crashtype *lkdtm_crashtype;
181
182/* Module parameters */
183static int recur_count = -1;
184module_param(recur_count, int, 0644);
185MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
186
187static char* cpoint_name;
188module_param(cpoint_name, charp, 0444);
189MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
190
191static char* cpoint_type;
192module_param(cpoint_type, charp, 0444);
193MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
194 "hitting the crash point");
195
196static int cpoint_count = DEFAULT_COUNT;
197module_param(cpoint_count, int, 0644);
198MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
199 "crash point is to be hit to trigger action");
200
201
202/* Return the crashtype number or NULL if the name is invalid */
203static const struct crashtype *find_crashtype(const char *name)
204{
205 int i;
206
207 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
208 if (!strcmp(name, crashtypes[i].name))
209 return &crashtypes[i];
210 }
211
212 return NULL;
213}
214
215/*
216 * This is forced noinline just so it distinctly shows up in the stackdump
217 * which makes validation of expected lkdtm crashes easier.
218 */
219static noinline void lkdtm_do_action(const struct crashtype *crashtype)
220{
221 if (WARN_ON(!crashtype || !crashtype->func))
222 return;
223 crashtype->func();
224}
225
226static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
227 const struct crashtype *crashtype)
228{
229 int ret;
230
231 /* If this doesn't have a symbol, just call immediately. */
232 if (!crashpoint->kprobe.symbol_name) {
233 lkdtm_do_action(crashtype);
234 return 0;
235 }
236
237 if (lkdtm_kprobe != NULL)
238 unregister_kprobe(lkdtm_kprobe);
239
240 lkdtm_crashpoint = crashpoint;
241 lkdtm_crashtype = crashtype;
242 lkdtm_kprobe = &crashpoint->kprobe;
243 ret = register_kprobe(lkdtm_kprobe);
244 if (ret < 0) {
245 pr_info("Couldn't register kprobe %s\n",
246 crashpoint->kprobe.symbol_name);
247 lkdtm_kprobe = NULL;
248 lkdtm_crashpoint = NULL;
249 lkdtm_crashtype = NULL;
250 }
251
252 return ret;
253}
254
255#ifdef CONFIG_KPROBES
256/* Global crash counter and spinlock. */
257static int crash_count = DEFAULT_COUNT;
258static DEFINE_SPINLOCK(crash_count_lock);
259
260/* Called by kprobe entry points. */
261static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
262{
263 unsigned long flags;
264 bool do_it = false;
265
266 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
267 return 0;
268
269 spin_lock_irqsave(&crash_count_lock, flags);
270 crash_count--;
271 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
272 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
273
274 if (crash_count == 0) {
275 do_it = true;
276 crash_count = cpoint_count;
277 }
278 spin_unlock_irqrestore(&crash_count_lock, flags);
279
280 if (do_it)
281 lkdtm_do_action(lkdtm_crashtype);
282
283 return 0;
284}
285
286static ssize_t lkdtm_debugfs_entry(struct file *f,
287 const char __user *user_buf,
288 size_t count, loff_t *off)
289{
290 struct crashpoint *crashpoint = file_inode(f)->i_private;
291 const struct crashtype *crashtype = NULL;
292 char *buf;
293 int err;
294
295 if (count >= PAGE_SIZE)
296 return -EINVAL;
297
298 buf = (char *)__get_free_page(GFP_KERNEL);
299 if (!buf)
300 return -ENOMEM;
301 if (copy_from_user(buf, user_buf, count)) {
302 free_page((unsigned long) buf);
303 return -EFAULT;
304 }
305 /* NULL-terminate and remove enter */
306 buf[count] = '\0';
307 strim(buf);
308
309 crashtype = find_crashtype(buf);
310 free_page((unsigned long)buf);
311
312 if (!crashtype)
313 return -EINVAL;
314
315 err = lkdtm_register_cpoint(crashpoint, crashtype);
316 if (err < 0)
317 return err;
318
319 *off += count;
320
321 return count;
322}
323#endif
324
325/* Generic read callback that just prints out the available crash types */
326static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
327 size_t count, loff_t *off)
328{
329 char *buf;
330 int i, n, out;
331
332 buf = (char *)__get_free_page(GFP_KERNEL);
333 if (buf == NULL)
334 return -ENOMEM;
335
336 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
337 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
338 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
339 crashtypes[i].name);
340 }
341 buf[n] = '\0';
342
343 out = simple_read_from_buffer(user_buf, count, off,
344 buf, n);
345 free_page((unsigned long) buf);
346
347 return out;
348}
349
350static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
351{
352 return 0;
353}
354
355/* Special entry to just crash directly. Available without KPROBEs */
356static ssize_t direct_entry(struct file *f, const char __user *user_buf,
357 size_t count, loff_t *off)
358{
359 const struct crashtype *crashtype;
360 char *buf;
361
362 if (count >= PAGE_SIZE)
363 return -EINVAL;
364 if (count < 1)
365 return -EINVAL;
366
367 buf = (char *)__get_free_page(GFP_KERNEL);
368 if (!buf)
369 return -ENOMEM;
370 if (copy_from_user(buf, user_buf, count)) {
371 free_page((unsigned long) buf);
372 return -EFAULT;
373 }
374 /* NULL-terminate and remove enter */
375 buf[count] = '\0';
376 strim(buf);
377
378 crashtype = find_crashtype(buf);
379 free_page((unsigned long) buf);
380 if (!crashtype)
381 return -EINVAL;
382
383 pr_info("Performing direct entry %s\n", crashtype->name);
384 lkdtm_do_action(crashtype);
385 *off += count;
386
387 return count;
388}
389
390static struct dentry *lkdtm_debugfs_root;
391
392static int __init lkdtm_module_init(void)
393{
394 struct crashpoint *crashpoint = NULL;
395 const struct crashtype *crashtype = NULL;
396 int ret;
397 int i;
398
399 /* Neither or both of these need to be set */
400 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
401 pr_err("Need both cpoint_type and cpoint_name or neither\n");
402 return -EINVAL;
403 }
404
405 if (cpoint_type) {
406 crashtype = find_crashtype(cpoint_type);
407 if (!crashtype) {
408 pr_err("Unknown crashtype '%s'\n", cpoint_type);
409 return -EINVAL;
410 }
411 }
412
413 if (cpoint_name) {
414 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
415 if (!strcmp(cpoint_name, crashpoints[i].name))
416 crashpoint = &crashpoints[i];
417 }
418
419 /* Refuse unknown crashpoints. */
420 if (!crashpoint) {
421 pr_err("Invalid crashpoint %s\n", cpoint_name);
422 return -EINVAL;
423 }
424 }
425
426#ifdef CONFIG_KPROBES
427 /* Set crash count. */
428 crash_count = cpoint_count;
429#endif
430
431 /* Handle test-specific initialization. */
432 lkdtm_bugs_init(&recur_count);
433 lkdtm_perms_init();
434 lkdtm_usercopy_init();
435 lkdtm_heap_init();
436
437 /* Register debugfs interface */
438 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
439
440 /* Install debugfs trigger files. */
441 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
442 struct crashpoint *cur = &crashpoints[i];
443
444 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
445 &cur->fops);
446 }
447
448 /* Install crashpoint if one was selected. */
449 if (crashpoint) {
450 ret = lkdtm_register_cpoint(crashpoint, crashtype);
451 if (ret < 0) {
452 pr_info("Invalid crashpoint %s\n", crashpoint->name);
453 goto out_err;
454 }
455 pr_info("Crash point %s of type %s registered\n",
456 crashpoint->name, cpoint_type);
457 } else {
458 pr_info("No crash points registered, enable through debugfs\n");
459 }
460
461 return 0;
462
463out_err:
464 debugfs_remove_recursive(lkdtm_debugfs_root);
465 return ret;
466}
467
468static void __exit lkdtm_module_exit(void)
469{
470 debugfs_remove_recursive(lkdtm_debugfs_root);
471
472 /* Handle test-specific clean-up. */
473 lkdtm_heap_exit();
474 lkdtm_usercopy_exit();
475
476 if (lkdtm_kprobe != NULL)
477 unregister_kprobe(lkdtm_kprobe);
478
479 pr_info("Crash point unregistered\n");
480}
481
482module_init(lkdtm_module_init);
483module_exit(lkdtm_module_exit);
484
485MODULE_LICENSE("GPL");
486MODULE_DESCRIPTION("Kernel crash testing module");