1 /*
2 * Linux Kernel Dump Test Module for testing kernel crashes conditions:
3 * induces system failures at predefined crashpoints and under predefined
4 * operational conditions in order to evaluate the reliability of kernel
5 * sanity checking and crash dumps obtained using different dumping
6 * solutions.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 *
22 * Copyright (C) IBM Corporation, 2006
23 *
24 * Author: Ankita Garg <ankita@in.ibm.com>
25 *
26 * It is adapted from the Linux Kernel Dump Test Tool by
27 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
28 *
29 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
30 *
31 * See Documentation/fault-injection/provoke-crashes.txt for instructions
32 */
33 #include "lkdtm.h"
34 #include <linux/fs.h>
35 #include <linux/module.h>
36 #include <linux/buffer_head.h>
37 #include <linux/kprobes.h>
38 #include <linux/list.h>
39 #include <linux/init.h>
40 #include <linux/interrupt.h>
41 #include <linux/hrtimer.h>
42 #include <linux/slab.h>
43 #include <scsi/scsi_cmnd.h>
44 #include <linux/debugfs.h>
45
46 #ifdef CONFIG_IDE
47 #include <linux/ide.h>
48 #endif
49
50 #define DEFAULT_COUNT 10
51
52 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
53 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
54 size_t count, loff_t *off);
55 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
56 size_t count, loff_t *off);
57
58 #ifdef CONFIG_KPROBES
59 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
60 static ssize_t lkdtm_debugfs_entry(struct file *f,
61 const char __user *user_buf,
62 size_t count, loff_t *off);
63 # define CRASHPOINT_KPROBE(_symbol) \
64 .kprobe = { \
65 .symbol_name = (_symbol), \
66 .pre_handler = lkdtm_kprobe_handler, \
67 },
68 # define CRASHPOINT_WRITE(_symbol) \
69 (_symbol) ? lkdtm_debugfs_entry : direct_entry
70 #else
71 # define CRASHPOINT_KPROBE(_symbol)
72 # define CRASHPOINT_WRITE(_symbol) direct_entry
73 #endif
74
75 /* Crash points */
76 struct crashpoint {
77 const char *name;
78 const struct file_operations fops;
79 struct kprobe kprobe;
80 };
81
82 #define CRASHPOINT(_name, _symbol) \
83 { \
84 .name = _name, \
85 .fops = { \
86 .read = lkdtm_debugfs_read, \
87 .llseek = generic_file_llseek, \
88 .open = lkdtm_debugfs_open, \
89 .write = CRASHPOINT_WRITE(_symbol) \
90 }, \
91 CRASHPOINT_KPROBE(_symbol) \
92 }
93
94 /* Define the possible places where we can trigger a crash point. */
95 static struct crashpoint crashpoints[] = {
96 CRASHPOINT("DIRECT", NULL),
97 #ifdef CONFIG_KPROBES
98 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
99 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
100 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
101 CRASHPOINT("FS_DEVRW", "ll_rw_block"),
102 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
103 CRASHPOINT("TIMERADD", "hrtimer_start"),
104 CRASHPOINT("SCSI_DISPATCH_CMD", "scsi_dispatch_cmd"),
105 # ifdef CONFIG_IDE
106 CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"),
107 # endif
108 #endif
109 };
110
111
112 /* Crash types. */
113 struct crashtype {
114 const char *name;
115 void (*func)(void);
116 };
117
118 #define CRASHTYPE(_name) \
119 { \
120 .name = __stringify(_name), \
121 .func = lkdtm_ ## _name, \
122 }
123
124 /* Define the possible types of crashes that can be triggered. */
125 static const struct crashtype crashtypes[] = {
126 CRASHTYPE(PANIC),
127 CRASHTYPE(BUG),
128 CRASHTYPE(WARNING),
129 CRASHTYPE(EXCEPTION),
130 CRASHTYPE(LOOP),
131 CRASHTYPE(OVERFLOW),
132 CRASHTYPE(CORRUPT_LIST_ADD),
133 CRASHTYPE(CORRUPT_LIST_DEL),
134 CRASHTYPE(CORRUPT_USER_DS),
135 CRASHTYPE(CORRUPT_STACK),
136 CRASHTYPE(CORRUPT_STACK_STRONG),
137 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
138 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
139 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
140 CRASHTYPE(OVERWRITE_ALLOCATION),
141 CRASHTYPE(WRITE_AFTER_FREE),
142 CRASHTYPE(READ_AFTER_FREE),
143 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
144 CRASHTYPE(READ_BUDDY_AFTER_FREE),
145 CRASHTYPE(SOFTLOCKUP),
146 CRASHTYPE(HARDLOCKUP),
147 CRASHTYPE(SPINLOCKUP),
148 CRASHTYPE(HUNG_TASK),
149 CRASHTYPE(EXEC_DATA),
150 CRASHTYPE(EXEC_STACK),
151 CRASHTYPE(EXEC_KMALLOC),
152 CRASHTYPE(EXEC_VMALLOC),
153 CRASHTYPE(EXEC_RODATA),
154 CRASHTYPE(EXEC_USERSPACE),
155 CRASHTYPE(EXEC_NULL),
156 CRASHTYPE(ACCESS_USERSPACE),
157 CRASHTYPE(ACCESS_NULL),
158 CRASHTYPE(WRITE_RO),
159 CRASHTYPE(WRITE_RO_AFTER_INIT),
160 CRASHTYPE(WRITE_KERN),
161 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
162 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
163 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
164 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
165 CRASHTYPE(REFCOUNT_DEC_ZERO),
166 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
167 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
168 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
169 CRASHTYPE(REFCOUNT_INC_ZERO),
170 CRASHTYPE(REFCOUNT_ADD_ZERO),
171 CRASHTYPE(REFCOUNT_INC_SATURATED),
172 CRASHTYPE(REFCOUNT_DEC_SATURATED),
173 CRASHTYPE(REFCOUNT_ADD_SATURATED),
174 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
175 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
176 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
177 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
178 CRASHTYPE(REFCOUNT_TIMING),
179 CRASHTYPE(ATOMIC_TIMING),
180 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
181 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
182 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
183 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
184 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
185 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
186 CRASHTYPE(USERCOPY_STACK_BEYOND),
187 CRASHTYPE(USERCOPY_KERNEL),
188 };
189
190
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;
195
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");
200
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");
204
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");
209
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");
214
215
216 /* Return the crashtype number or NULL if the name is invalid */
find_crashtype(const char * name)217 static const struct crashtype *find_crashtype(const char *name)
218 {
219 int i;
220
221 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
222 if (!strcmp(name, crashtypes[i].name))
223 return &crashtypes[i];
224 }
225
226 return NULL;
227 }
228
229 /*
230 * This is forced noinline just so it distinctly shows up in the stackdump
231 * which makes validation of expected lkdtm crashes easier.
232 */
lkdtm_do_action(const struct crashtype * crashtype)233 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
234 {
235 if (WARN_ON(!crashtype || !crashtype->func))
236 return;
237 crashtype->func();
238 }
239
lkdtm_register_cpoint(struct crashpoint * crashpoint,const struct crashtype * crashtype)240 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
241 const struct crashtype *crashtype)
242 {
243 int ret;
244
245 /* If this doesn't have a symbol, just call immediately. */
246 if (!crashpoint->kprobe.symbol_name) {
247 lkdtm_do_action(crashtype);
248 return 0;
249 }
250
251 if (lkdtm_kprobe != NULL)
252 unregister_kprobe(lkdtm_kprobe);
253
254 lkdtm_crashpoint = crashpoint;
255 lkdtm_crashtype = crashtype;
256 lkdtm_kprobe = &crashpoint->kprobe;
257 ret = register_kprobe(lkdtm_kprobe);
258 if (ret < 0) {
259 pr_info("Couldn't register kprobe %s\n",
260 crashpoint->kprobe.symbol_name);
261 lkdtm_kprobe = NULL;
262 lkdtm_crashpoint = NULL;
263 lkdtm_crashtype = NULL;
264 }
265
266 return ret;
267 }
268
269 #ifdef CONFIG_KPROBES
270 /* Global crash counter and spinlock. */
271 static int crash_count = DEFAULT_COUNT;
272 static DEFINE_SPINLOCK(crash_count_lock);
273
274 /* Called by kprobe entry points. */
lkdtm_kprobe_handler(struct kprobe * kp,struct pt_regs * regs)275 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
276 {
277 unsigned long flags;
278 bool do_it = false;
279
280 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
281 return 0;
282
283 spin_lock_irqsave(&crash_count_lock, flags);
284 crash_count--;
285 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
286 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
287
288 if (crash_count == 0) {
289 do_it = true;
290 crash_count = cpoint_count;
291 }
292 spin_unlock_irqrestore(&crash_count_lock, flags);
293
294 if (do_it)
295 lkdtm_do_action(lkdtm_crashtype);
296
297 return 0;
298 }
299
lkdtm_debugfs_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)300 static ssize_t lkdtm_debugfs_entry(struct file *f,
301 const char __user *user_buf,
302 size_t count, loff_t *off)
303 {
304 struct crashpoint *crashpoint = file_inode(f)->i_private;
305 const struct crashtype *crashtype = NULL;
306 char *buf;
307 int err;
308
309 if (count >= PAGE_SIZE)
310 return -EINVAL;
311
312 buf = (char *)__get_free_page(GFP_KERNEL);
313 if (!buf)
314 return -ENOMEM;
315 if (copy_from_user(buf, user_buf, count)) {
316 free_page((unsigned long) buf);
317 return -EFAULT;
318 }
319 /* NULL-terminate and remove enter */
320 buf[count] = '\0';
321 strim(buf);
322
323 crashtype = find_crashtype(buf);
324 free_page((unsigned long)buf);
325
326 if (!crashtype)
327 return -EINVAL;
328
329 err = lkdtm_register_cpoint(crashpoint, crashtype);
330 if (err < 0)
331 return err;
332
333 *off += count;
334
335 return count;
336 }
337 #endif
338
339 /* Generic read callback that just prints out the available crash types */
lkdtm_debugfs_read(struct file * f,char __user * user_buf,size_t count,loff_t * off)340 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
341 size_t count, loff_t *off)
342 {
343 char *buf;
344 int i, n, out;
345
346 buf = (char *)__get_free_page(GFP_KERNEL);
347 if (buf == NULL)
348 return -ENOMEM;
349
350 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
351 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
352 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
353 crashtypes[i].name);
354 }
355 buf[n] = '\0';
356
357 out = simple_read_from_buffer(user_buf, count, off,
358 buf, n);
359 free_page((unsigned long) buf);
360
361 return out;
362 }
363
lkdtm_debugfs_open(struct inode * inode,struct file * file)364 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
365 {
366 return 0;
367 }
368
369 /* Special entry to just crash directly. Available without KPROBEs */
direct_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)370 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
371 size_t count, loff_t *off)
372 {
373 const struct crashtype *crashtype;
374 char *buf;
375
376 if (count >= PAGE_SIZE)
377 return -EINVAL;
378 if (count < 1)
379 return -EINVAL;
380
381 buf = (char *)__get_free_page(GFP_KERNEL);
382 if (!buf)
383 return -ENOMEM;
384 if (copy_from_user(buf, user_buf, count)) {
385 free_page((unsigned long) buf);
386 return -EFAULT;
387 }
388 /* NULL-terminate and remove enter */
389 buf[count] = '\0';
390 strim(buf);
391
392 crashtype = find_crashtype(buf);
393 free_page((unsigned long) buf);
394 if (!crashtype)
395 return -EINVAL;
396
397 pr_info("Performing direct entry %s\n", crashtype->name);
398 lkdtm_do_action(crashtype);
399 *off += count;
400
401 return count;
402 }
403
404 static struct dentry *lkdtm_debugfs_root;
405
lkdtm_module_init(void)406 static int __init lkdtm_module_init(void)
407 {
408 struct crashpoint *crashpoint = NULL;
409 const struct crashtype *crashtype = NULL;
410 int ret = -EINVAL;
411 int i;
412
413 /* Neither or both of these need to be set */
414 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
415 pr_err("Need both cpoint_type and cpoint_name or neither\n");
416 return -EINVAL;
417 }
418
419 if (cpoint_type) {
420 crashtype = find_crashtype(cpoint_type);
421 if (!crashtype) {
422 pr_err("Unknown crashtype '%s'\n", cpoint_type);
423 return -EINVAL;
424 }
425 }
426
427 if (cpoint_name) {
428 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
429 if (!strcmp(cpoint_name, crashpoints[i].name))
430 crashpoint = &crashpoints[i];
431 }
432
433 /* Refuse unknown crashpoints. */
434 if (!crashpoint) {
435 pr_err("Invalid crashpoint %s\n", cpoint_name);
436 return -EINVAL;
437 }
438 }
439
440 #ifdef CONFIG_KPROBES
441 /* Set crash count. */
442 crash_count = cpoint_count;
443 #endif
444
445 /* Handle test-specific initialization. */
446 lkdtm_bugs_init(&recur_count);
447 lkdtm_perms_init();
448 lkdtm_usercopy_init();
449
450 /* Register debugfs interface */
451 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
452 if (!lkdtm_debugfs_root) {
453 pr_err("creating root dir failed\n");
454 return -ENODEV;
455 }
456
457 /* Install debugfs trigger files. */
458 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
459 struct crashpoint *cur = &crashpoints[i];
460 struct dentry *de;
461
462 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
463 cur, &cur->fops);
464 if (de == NULL) {
465 pr_err("could not create crashpoint %s\n", cur->name);
466 goto out_err;
467 }
468 }
469
470 /* Install crashpoint if one was selected. */
471 if (crashpoint) {
472 ret = lkdtm_register_cpoint(crashpoint, crashtype);
473 if (ret < 0) {
474 pr_info("Invalid crashpoint %s\n", crashpoint->name);
475 goto out_err;
476 }
477 pr_info("Crash point %s of type %s registered\n",
478 crashpoint->name, cpoint_type);
479 } else {
480 pr_info("No crash points registered, enable through debugfs\n");
481 }
482
483 return 0;
484
485 out_err:
486 debugfs_remove_recursive(lkdtm_debugfs_root);
487 return ret;
488 }
489
lkdtm_module_exit(void)490 static void __exit lkdtm_module_exit(void)
491 {
492 debugfs_remove_recursive(lkdtm_debugfs_root);
493
494 /* Handle test-specific clean-up. */
495 lkdtm_usercopy_exit();
496
497 if (lkdtm_kprobe != NULL)
498 unregister_kprobe(lkdtm_kprobe);
499
500 pr_info("Crash point unregistered\n");
501 }
502
503 module_init(lkdtm_module_init);
504 module_exit(lkdtm_module_exit);
505
506 MODULE_LICENSE("GPL");
507 MODULE_DESCRIPTION("Kernel crash testing module");
508