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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(CORRUPT_PAC),
120 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
121 CRASHTYPE(OVERWRITE_ALLOCATION),
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_FREE_DOUBLE),
127 CRASHTYPE(SLAB_FREE_CROSS),
128 CRASHTYPE(SLAB_FREE_PAGE),
129 CRASHTYPE(SOFTLOCKUP),
130 CRASHTYPE(HARDLOCKUP),
131 CRASHTYPE(SPINLOCKUP),
132 CRASHTYPE(HUNG_TASK),
133 CRASHTYPE(OVERFLOW_SIGNED),
134 CRASHTYPE(OVERFLOW_UNSIGNED),
135 CRASHTYPE(ARRAY_BOUNDS),
136 CRASHTYPE(EXEC_DATA),
137 CRASHTYPE(EXEC_STACK),
138 CRASHTYPE(EXEC_KMALLOC),
139 CRASHTYPE(EXEC_VMALLOC),
140 CRASHTYPE(EXEC_RODATA),
141 CRASHTYPE(EXEC_USERSPACE),
142 CRASHTYPE(EXEC_NULL),
143 CRASHTYPE(ACCESS_USERSPACE),
144 CRASHTYPE(ACCESS_NULL),
145 CRASHTYPE(WRITE_RO),
146 CRASHTYPE(WRITE_RO_AFTER_INIT),
147 CRASHTYPE(WRITE_KERN),
148 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
149 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
150 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
151 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
152 CRASHTYPE(REFCOUNT_DEC_ZERO),
153 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
154 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
155 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
156 CRASHTYPE(REFCOUNT_INC_ZERO),
157 CRASHTYPE(REFCOUNT_ADD_ZERO),
158 CRASHTYPE(REFCOUNT_INC_SATURATED),
159 CRASHTYPE(REFCOUNT_DEC_SATURATED),
160 CRASHTYPE(REFCOUNT_ADD_SATURATED),
161 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
162 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
163 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
164 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
165 CRASHTYPE(REFCOUNT_TIMING),
166 CRASHTYPE(ATOMIC_TIMING),
167 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
168 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
169 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
170 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
171 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
172 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
173 CRASHTYPE(USERCOPY_STACK_BEYOND),
174 CRASHTYPE(USERCOPY_KERNEL),
175 CRASHTYPE(USERCOPY_KERNEL_DS),
176 CRASHTYPE(STACKLEAK_ERASING),
177 CRASHTYPE(CFI_FORWARD_PROTO),
178#ifdef CONFIG_X86_32
179 CRASHTYPE(DOUBLE_FAULT),
180#endif
181};
182
183
184/* Global kprobe entry and crashtype. */
185static struct kprobe *lkdtm_kprobe;
186static struct crashpoint *lkdtm_crashpoint;
187static const struct crashtype *lkdtm_crashtype;
188
189/* Module parameters */
190static int recur_count = -1;
191module_param(recur_count, int, 0644);
192MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
193
194static char* cpoint_name;
195module_param(cpoint_name, charp, 0444);
196MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
197
198static char* cpoint_type;
199module_param(cpoint_type, charp, 0444);
200MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
201 "hitting the crash point");
202
203static int cpoint_count = DEFAULT_COUNT;
204module_param(cpoint_count, int, 0644);
205MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
206 "crash point is to be hit to trigger action");
207
208
209/* Return the crashtype number or NULL if the name is invalid */
210static const struct crashtype *find_crashtype(const char *name)
211{
212 int i;
213
214 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
215 if (!strcmp(name, crashtypes[i].name))
216 return &crashtypes[i];
217 }
218
219 return NULL;
220}
221
222/*
223 * This is forced noinline just so it distinctly shows up in the stackdump
224 * which makes validation of expected lkdtm crashes easier.
225 */
226static noinline void lkdtm_do_action(const struct crashtype *crashtype)
227{
228 if (WARN_ON(!crashtype || !crashtype->func))
229 return;
230 crashtype->func();
231}
232
233static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
234 const struct crashtype *crashtype)
235{
236 int ret;
237
238 /* If this doesn't have a symbol, just call immediately. */
239 if (!crashpoint->kprobe.symbol_name) {
240 lkdtm_do_action(crashtype);
241 return 0;
242 }
243
244 if (lkdtm_kprobe != NULL)
245 unregister_kprobe(lkdtm_kprobe);
246
247 lkdtm_crashpoint = crashpoint;
248 lkdtm_crashtype = crashtype;
249 lkdtm_kprobe = &crashpoint->kprobe;
250 ret = register_kprobe(lkdtm_kprobe);
251 if (ret < 0) {
252 pr_info("Couldn't register kprobe %s\n",
253 crashpoint->kprobe.symbol_name);
254 lkdtm_kprobe = NULL;
255 lkdtm_crashpoint = NULL;
256 lkdtm_crashtype = NULL;
257 }
258
259 return ret;
260}
261
262#ifdef CONFIG_KPROBES
263/* Global crash counter and spinlock. */
264static int crash_count = DEFAULT_COUNT;
265static DEFINE_SPINLOCK(crash_count_lock);
266
267/* Called by kprobe entry points. */
268static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
269{
270 unsigned long flags;
271 bool do_it = false;
272
273 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
274 return 0;
275
276 spin_lock_irqsave(&crash_count_lock, flags);
277 crash_count--;
278 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
279 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
280
281 if (crash_count == 0) {
282 do_it = true;
283 crash_count = cpoint_count;
284 }
285 spin_unlock_irqrestore(&crash_count_lock, flags);
286
287 if (do_it)
288 lkdtm_do_action(lkdtm_crashtype);
289
290 return 0;
291}
292
293static ssize_t lkdtm_debugfs_entry(struct file *f,
294 const char __user *user_buf,
295 size_t count, loff_t *off)
296{
297 struct crashpoint *crashpoint = file_inode(f)->i_private;
298 const struct crashtype *crashtype = NULL;
299 char *buf;
300 int err;
301
302 if (count >= PAGE_SIZE)
303 return -EINVAL;
304
305 buf = (char *)__get_free_page(GFP_KERNEL);
306 if (!buf)
307 return -ENOMEM;
308 if (copy_from_user(buf, user_buf, count)) {
309 free_page((unsigned long) buf);
310 return -EFAULT;
311 }
312 /* NULL-terminate and remove enter */
313 buf[count] = '\0';
314 strim(buf);
315
316 crashtype = find_crashtype(buf);
317 free_page((unsigned long)buf);
318
319 if (!crashtype)
320 return -EINVAL;
321
322 err = lkdtm_register_cpoint(crashpoint, crashtype);
323 if (err < 0)
324 return err;
325
326 *off += count;
327
328 return count;
329}
330#endif
331
332/* Generic read callback that just prints out the available crash types */
333static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
334 size_t count, loff_t *off)
335{
336 char *buf;
337 int i, n, out;
338
339 buf = (char *)__get_free_page(GFP_KERNEL);
340 if (buf == NULL)
341 return -ENOMEM;
342
343 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
344 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
345 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
346 crashtypes[i].name);
347 }
348 buf[n] = '\0';
349
350 out = simple_read_from_buffer(user_buf, count, off,
351 buf, n);
352 free_page((unsigned long) buf);
353
354 return out;
355}
356
357static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
358{
359 return 0;
360}
361
362/* Special entry to just crash directly. Available without KPROBEs */
363static ssize_t direct_entry(struct file *f, const char __user *user_buf,
364 size_t count, loff_t *off)
365{
366 const struct crashtype *crashtype;
367 char *buf;
368
369 if (count >= PAGE_SIZE)
370 return -EINVAL;
371 if (count < 1)
372 return -EINVAL;
373
374 buf = (char *)__get_free_page(GFP_KERNEL);
375 if (!buf)
376 return -ENOMEM;
377 if (copy_from_user(buf, user_buf, count)) {
378 free_page((unsigned long) buf);
379 return -EFAULT;
380 }
381 /* NULL-terminate and remove enter */
382 buf[count] = '\0';
383 strim(buf);
384
385 crashtype = find_crashtype(buf);
386 free_page((unsigned long) buf);
387 if (!crashtype)
388 return -EINVAL;
389
390 pr_info("Performing direct entry %s\n", crashtype->name);
391 lkdtm_do_action(crashtype);
392 *off += count;
393
394 return count;
395}
396
397static struct dentry *lkdtm_debugfs_root;
398
399static int __init lkdtm_module_init(void)
400{
401 struct crashpoint *crashpoint = NULL;
402 const struct crashtype *crashtype = NULL;
403 int ret;
404 int i;
405
406 /* Neither or both of these need to be set */
407 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
408 pr_err("Need both cpoint_type and cpoint_name or neither\n");
409 return -EINVAL;
410 }
411
412 if (cpoint_type) {
413 crashtype = find_crashtype(cpoint_type);
414 if (!crashtype) {
415 pr_err("Unknown crashtype '%s'\n", cpoint_type);
416 return -EINVAL;
417 }
418 }
419
420 if (cpoint_name) {
421 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
422 if (!strcmp(cpoint_name, crashpoints[i].name))
423 crashpoint = &crashpoints[i];
424 }
425
426 /* Refuse unknown crashpoints. */
427 if (!crashpoint) {
428 pr_err("Invalid crashpoint %s\n", cpoint_name);
429 return -EINVAL;
430 }
431 }
432
433#ifdef CONFIG_KPROBES
434 /* Set crash count. */
435 crash_count = cpoint_count;
436#endif
437
438 /* Handle test-specific initialization. */
439 lkdtm_bugs_init(&recur_count);
440 lkdtm_perms_init();
441 lkdtm_usercopy_init();
442 lkdtm_heap_init();
443
444 /* Register debugfs interface */
445 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
446
447 /* Install debugfs trigger files. */
448 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
449 struct crashpoint *cur = &crashpoints[i];
450
451 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
452 &cur->fops);
453 }
454
455 /* Install crashpoint if one was selected. */
456 if (crashpoint) {
457 ret = lkdtm_register_cpoint(crashpoint, crashtype);
458 if (ret < 0) {
459 pr_info("Invalid crashpoint %s\n", crashpoint->name);
460 goto out_err;
461 }
462 pr_info("Crash point %s of type %s registered\n",
463 crashpoint->name, cpoint_type);
464 } else {
465 pr_info("No crash points registered, enable through debugfs\n");
466 }
467
468 return 0;
469
470out_err:
471 debugfs_remove_recursive(lkdtm_debugfs_root);
472 return ret;
473}
474
475static void __exit lkdtm_module_exit(void)
476{
477 debugfs_remove_recursive(lkdtm_debugfs_root);
478
479 /* Handle test-specific clean-up. */
480 lkdtm_heap_exit();
481 lkdtm_usercopy_exit();
482
483 if (lkdtm_kprobe != NULL)
484 unregister_kprobe(lkdtm_kprobe);
485
486 pr_info("Crash point unregistered\n");
487}
488
489module_init(lkdtm_module_init);
490module_exit(lkdtm_module_exit);
491
492MODULE_LICENSE("GPL");
493MODULE_DESCRIPTION("Kernel crash testing module");