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 void lkdtm_handler(void);
60 static ssize_t lkdtm_debugfs_entry(struct file *f,
61 const char __user *user_buf,
62 size_t count, loff_t *off);
63
64
65 /* jprobe entry point handlers. */
jp_do_irq(unsigned int irq)66 static unsigned int jp_do_irq(unsigned int irq)
67 {
68 lkdtm_handler();
69 jprobe_return();
70 return 0;
71 }
72
jp_handle_irq_event(unsigned int irq,struct irqaction * action)73 static irqreturn_t jp_handle_irq_event(unsigned int irq,
74 struct irqaction *action)
75 {
76 lkdtm_handler();
77 jprobe_return();
78 return 0;
79 }
80
jp_tasklet_action(struct softirq_action * a)81 static void jp_tasklet_action(struct softirq_action *a)
82 {
83 lkdtm_handler();
84 jprobe_return();
85 }
86
jp_ll_rw_block(int rw,int nr,struct buffer_head * bhs[])87 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
88 {
89 lkdtm_handler();
90 jprobe_return();
91 }
92
93 struct scan_control;
94
jp_shrink_inactive_list(unsigned long max_scan,struct zone * zone,struct scan_control * sc)95 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
96 struct zone *zone,
97 struct scan_control *sc)
98 {
99 lkdtm_handler();
100 jprobe_return();
101 return 0;
102 }
103
jp_hrtimer_start(struct hrtimer * timer,ktime_t tim,const enum hrtimer_mode mode)104 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
105 const enum hrtimer_mode mode)
106 {
107 lkdtm_handler();
108 jprobe_return();
109 return 0;
110 }
111
jp_scsi_dispatch_cmd(struct scsi_cmnd * cmd)112 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
113 {
114 lkdtm_handler();
115 jprobe_return();
116 return 0;
117 }
118
119 # ifdef CONFIG_IDE
jp_generic_ide_ioctl(ide_drive_t * drive,struct file * file,struct block_device * bdev,unsigned int cmd,unsigned long arg)120 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
121 struct block_device *bdev, unsigned int cmd,
122 unsigned long arg)
123 {
124 lkdtm_handler();
125 jprobe_return();
126 return 0;
127 }
128 # endif
129 #endif
130
131 /* Crash points */
132 struct crashpoint {
133 const char *name;
134 const struct file_operations fops;
135 struct jprobe jprobe;
136 };
137
138 #define CRASHPOINT(_name, _write, _symbol, _entry) \
139 { \
140 .name = _name, \
141 .fops = { \
142 .read = lkdtm_debugfs_read, \
143 .llseek = generic_file_llseek, \
144 .open = lkdtm_debugfs_open, \
145 .write = _write, \
146 }, \
147 .jprobe = { \
148 .kp.symbol_name = _symbol, \
149 .entry = (kprobe_opcode_t *)_entry, \
150 }, \
151 }
152
153 /* Define the possible places where we can trigger a crash point. */
154 struct crashpoint crashpoints[] = {
155 CRASHPOINT("DIRECT", direct_entry,
156 NULL, NULL),
157 #ifdef CONFIG_KPROBES
158 CRASHPOINT("INT_HARDWARE_ENTRY", lkdtm_debugfs_entry,
159 "do_IRQ", jp_do_irq),
160 CRASHPOINT("INT_HW_IRQ_EN", lkdtm_debugfs_entry,
161 "handle_IRQ_event", jp_handle_irq_event),
162 CRASHPOINT("INT_TASKLET_ENTRY", lkdtm_debugfs_entry,
163 "tasklet_action", jp_tasklet_action),
164 CRASHPOINT("FS_DEVRW", lkdtm_debugfs_entry,
165 "ll_rw_block", jp_ll_rw_block),
166 CRASHPOINT("MEM_SWAPOUT", lkdtm_debugfs_entry,
167 "shrink_inactive_list", jp_shrink_inactive_list),
168 CRASHPOINT("TIMERADD", lkdtm_debugfs_entry,
169 "hrtimer_start", jp_hrtimer_start),
170 CRASHPOINT("SCSI_DISPATCH_CMD", lkdtm_debugfs_entry,
171 "scsi_dispatch_cmd", jp_scsi_dispatch_cmd),
172 # ifdef CONFIG_IDE
173 CRASHPOINT("IDE_CORE_CP", lkdtm_debugfs_entry,
174 "generic_ide_ioctl", jp_generic_ide_ioctl),
175 # endif
176 #endif
177 };
178
179
180 /* Crash types. */
181 struct crashtype {
182 const char *name;
183 void (*func)(void);
184 };
185
186 #define CRASHTYPE(_name) \
187 { \
188 .name = __stringify(_name), \
189 .func = lkdtm_ ## _name, \
190 }
191
192 /* Define the possible types of crashes that can be triggered. */
193 struct crashtype crashtypes[] = {
194 CRASHTYPE(PANIC),
195 CRASHTYPE(BUG),
196 CRASHTYPE(WARNING),
197 CRASHTYPE(EXCEPTION),
198 CRASHTYPE(LOOP),
199 CRASHTYPE(OVERFLOW),
200 CRASHTYPE(CORRUPT_LIST_ADD),
201 CRASHTYPE(CORRUPT_LIST_DEL),
202 CRASHTYPE(CORRUPT_USER_DS),
203 CRASHTYPE(CORRUPT_STACK),
204 CRASHTYPE(CORRUPT_STACK_STRONG),
205 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
206 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
207 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
208 CRASHTYPE(OVERWRITE_ALLOCATION),
209 CRASHTYPE(WRITE_AFTER_FREE),
210 CRASHTYPE(READ_AFTER_FREE),
211 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
212 CRASHTYPE(READ_BUDDY_AFTER_FREE),
213 CRASHTYPE(SOFTLOCKUP),
214 CRASHTYPE(HARDLOCKUP),
215 CRASHTYPE(SPINLOCKUP),
216 CRASHTYPE(HUNG_TASK),
217 CRASHTYPE(EXEC_DATA),
218 CRASHTYPE(EXEC_STACK),
219 CRASHTYPE(EXEC_KMALLOC),
220 CRASHTYPE(EXEC_VMALLOC),
221 CRASHTYPE(EXEC_RODATA),
222 CRASHTYPE(EXEC_USERSPACE),
223 CRASHTYPE(EXEC_NULL),
224 CRASHTYPE(ACCESS_USERSPACE),
225 CRASHTYPE(ACCESS_NULL),
226 CRASHTYPE(WRITE_RO),
227 CRASHTYPE(WRITE_RO_AFTER_INIT),
228 CRASHTYPE(WRITE_KERN),
229 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
230 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
231 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
232 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
233 CRASHTYPE(REFCOUNT_DEC_ZERO),
234 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
235 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
236 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
237 CRASHTYPE(REFCOUNT_INC_ZERO),
238 CRASHTYPE(REFCOUNT_ADD_ZERO),
239 CRASHTYPE(REFCOUNT_INC_SATURATED),
240 CRASHTYPE(REFCOUNT_DEC_SATURATED),
241 CRASHTYPE(REFCOUNT_ADD_SATURATED),
242 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
243 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
244 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
245 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
246 CRASHTYPE(REFCOUNT_TIMING),
247 CRASHTYPE(ATOMIC_TIMING),
248 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
249 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
250 CRASHTYPE(USERCOPY_HEAP_FLAG_TO),
251 CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
252 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
253 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
254 CRASHTYPE(USERCOPY_STACK_BEYOND),
255 CRASHTYPE(USERCOPY_KERNEL),
256 };
257
258
259 /* Global jprobe entry and crashtype. */
260 static struct jprobe *lkdtm_jprobe;
261 struct crashpoint *lkdtm_crashpoint;
262 struct crashtype *lkdtm_crashtype;
263
264 /* Module parameters */
265 static int recur_count = -1;
266 module_param(recur_count, int, 0644);
267 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
268
269 static char* cpoint_name;
270 module_param(cpoint_name, charp, 0444);
271 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
272
273 static char* cpoint_type;
274 module_param(cpoint_type, charp, 0444);
275 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
276 "hitting the crash point");
277
278 static int cpoint_count = DEFAULT_COUNT;
279 module_param(cpoint_count, int, 0644);
280 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
281 "crash point is to be hit to trigger action");
282
283
284 /* Return the crashtype number or NULL if the name is invalid */
find_crashtype(const char * name)285 static struct crashtype *find_crashtype(const char *name)
286 {
287 int i;
288
289 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
290 if (!strcmp(name, crashtypes[i].name))
291 return &crashtypes[i];
292 }
293
294 return NULL;
295 }
296
297 /*
298 * This is forced noinline just so it distinctly shows up in the stackdump
299 * which makes validation of expected lkdtm crashes easier.
300 */
lkdtm_do_action(struct crashtype * crashtype)301 static noinline void lkdtm_do_action(struct crashtype *crashtype)
302 {
303 BUG_ON(!crashtype || !crashtype->func);
304 crashtype->func();
305 }
306
lkdtm_register_cpoint(struct crashpoint * crashpoint,struct crashtype * crashtype)307 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
308 struct crashtype *crashtype)
309 {
310 int ret;
311
312 /* If this doesn't have a symbol, just call immediately. */
313 if (!crashpoint->jprobe.kp.symbol_name) {
314 lkdtm_do_action(crashtype);
315 return 0;
316 }
317
318 if (lkdtm_jprobe != NULL)
319 unregister_jprobe(lkdtm_jprobe);
320
321 lkdtm_crashpoint = crashpoint;
322 lkdtm_crashtype = crashtype;
323 lkdtm_jprobe = &crashpoint->jprobe;
324 ret = register_jprobe(lkdtm_jprobe);
325 if (ret < 0) {
326 pr_info("Couldn't register jprobe %s\n",
327 crashpoint->jprobe.kp.symbol_name);
328 lkdtm_jprobe = NULL;
329 lkdtm_crashpoint = NULL;
330 lkdtm_crashtype = NULL;
331 }
332
333 return ret;
334 }
335
336 #ifdef CONFIG_KPROBES
337 /* Global crash counter and spinlock. */
338 static int crash_count = DEFAULT_COUNT;
339 static DEFINE_SPINLOCK(crash_count_lock);
340
341 /* Called by jprobe entry points. */
lkdtm_handler(void)342 static void lkdtm_handler(void)
343 {
344 unsigned long flags;
345 bool do_it = false;
346
347 BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
348
349 spin_lock_irqsave(&crash_count_lock, flags);
350 crash_count--;
351 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
352 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
353
354 if (crash_count == 0) {
355 do_it = true;
356 crash_count = cpoint_count;
357 }
358 spin_unlock_irqrestore(&crash_count_lock, flags);
359
360 if (do_it)
361 lkdtm_do_action(lkdtm_crashtype);
362 }
363
lkdtm_debugfs_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)364 static ssize_t lkdtm_debugfs_entry(struct file *f,
365 const char __user *user_buf,
366 size_t count, loff_t *off)
367 {
368 struct crashpoint *crashpoint = file_inode(f)->i_private;
369 struct crashtype *crashtype = NULL;
370 char *buf;
371 int err;
372
373 if (count >= PAGE_SIZE)
374 return -EINVAL;
375
376 buf = (char *)__get_free_page(GFP_KERNEL);
377 if (!buf)
378 return -ENOMEM;
379 if (copy_from_user(buf, user_buf, count)) {
380 free_page((unsigned long) buf);
381 return -EFAULT;
382 }
383 /* NULL-terminate and remove enter */
384 buf[count] = '\0';
385 strim(buf);
386
387 crashtype = find_crashtype(buf);
388 free_page((unsigned long)buf);
389
390 if (!crashtype)
391 return -EINVAL;
392
393 err = lkdtm_register_cpoint(crashpoint, crashtype);
394 if (err < 0)
395 return err;
396
397 *off += count;
398
399 return count;
400 }
401 #endif
402
403 /* 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)404 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
405 size_t count, loff_t *off)
406 {
407 char *buf;
408 int i, n, out;
409
410 buf = (char *)__get_free_page(GFP_KERNEL);
411 if (buf == NULL)
412 return -ENOMEM;
413
414 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
415 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
416 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
417 crashtypes[i].name);
418 }
419 buf[n] = '\0';
420
421 out = simple_read_from_buffer(user_buf, count, off,
422 buf, n);
423 free_page((unsigned long) buf);
424
425 return out;
426 }
427
lkdtm_debugfs_open(struct inode * inode,struct file * file)428 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
429 {
430 return 0;
431 }
432
433 /* 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)434 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
435 size_t count, loff_t *off)
436 {
437 struct crashtype *crashtype;
438 char *buf;
439
440 if (count >= PAGE_SIZE)
441 return -EINVAL;
442 if (count < 1)
443 return -EINVAL;
444
445 buf = (char *)__get_free_page(GFP_KERNEL);
446 if (!buf)
447 return -ENOMEM;
448 if (copy_from_user(buf, user_buf, count)) {
449 free_page((unsigned long) buf);
450 return -EFAULT;
451 }
452 /* NULL-terminate and remove enter */
453 buf[count] = '\0';
454 strim(buf);
455
456 crashtype = find_crashtype(buf);
457 free_page((unsigned long) buf);
458 if (!crashtype)
459 return -EINVAL;
460
461 pr_info("Performing direct entry %s\n", crashtype->name);
462 lkdtm_do_action(crashtype);
463 *off += count;
464
465 return count;
466 }
467
468 static struct dentry *lkdtm_debugfs_root;
469
lkdtm_module_init(void)470 static int __init lkdtm_module_init(void)
471 {
472 struct crashpoint *crashpoint = NULL;
473 struct crashtype *crashtype = NULL;
474 int ret = -EINVAL;
475 int i;
476
477 /* Neither or both of these need to be set */
478 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
479 pr_err("Need both cpoint_type and cpoint_name or neither\n");
480 return -EINVAL;
481 }
482
483 if (cpoint_type) {
484 crashtype = find_crashtype(cpoint_type);
485 if (!crashtype) {
486 pr_err("Unknown crashtype '%s'\n", cpoint_type);
487 return -EINVAL;
488 }
489 }
490
491 if (cpoint_name) {
492 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
493 if (!strcmp(cpoint_name, crashpoints[i].name))
494 crashpoint = &crashpoints[i];
495 }
496
497 /* Refuse unknown crashpoints. */
498 if (!crashpoint) {
499 pr_err("Invalid crashpoint %s\n", cpoint_name);
500 return -EINVAL;
501 }
502 }
503
504 #ifdef CONFIG_KPROBES
505 /* Set crash count. */
506 crash_count = cpoint_count;
507 #endif
508
509 /* Handle test-specific initialization. */
510 lkdtm_bugs_init(&recur_count);
511 lkdtm_perms_init();
512 lkdtm_usercopy_init();
513
514 /* Register debugfs interface */
515 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
516 if (!lkdtm_debugfs_root) {
517 pr_err("creating root dir failed\n");
518 return -ENODEV;
519 }
520
521 /* Install debugfs trigger files. */
522 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
523 struct crashpoint *cur = &crashpoints[i];
524 struct dentry *de;
525
526 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
527 cur, &cur->fops);
528 if (de == NULL) {
529 pr_err("could not create crashpoint %s\n", cur->name);
530 goto out_err;
531 }
532 }
533
534 /* Install crashpoint if one was selected. */
535 if (crashpoint) {
536 ret = lkdtm_register_cpoint(crashpoint, crashtype);
537 if (ret < 0) {
538 pr_info("Invalid crashpoint %s\n", crashpoint->name);
539 goto out_err;
540 }
541 pr_info("Crash point %s of type %s registered\n",
542 crashpoint->name, cpoint_type);
543 } else {
544 pr_info("No crash points registered, enable through debugfs\n");
545 }
546
547 return 0;
548
549 out_err:
550 debugfs_remove_recursive(lkdtm_debugfs_root);
551 return ret;
552 }
553
lkdtm_module_exit(void)554 static void __exit lkdtm_module_exit(void)
555 {
556 debugfs_remove_recursive(lkdtm_debugfs_root);
557
558 /* Handle test-specific clean-up. */
559 lkdtm_usercopy_exit();
560
561 if (lkdtm_jprobe != NULL)
562 unregister_jprobe(lkdtm_jprobe);
563
564 pr_info("Crash point unregistered\n");
565 }
566
567 module_init(lkdtm_module_init);
568 module_exit(lkdtm_module_exit);
569
570 MODULE_LICENSE("GPL");
571 MODULE_DESCRIPTION("Kernel crash testing module");
572