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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