lkdtm.c revision 0347af4ee3922220f6bfe74b87b526aa709a0365 
1/*
2 * Kprobe module for testing crash dumps
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2006
19 *
20 * Author: Ankita Garg <ankita@in.ibm.com>
21 *
22 * This module induces system failures at predefined crashpoints to
23 * evaluate the reliability of crash dumps obtained using different dumping
24 * solutions.
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
34#include <linux/kernel.h>
35#include <linux/fs.h>
36#include <linux/module.h>
37#include <linux/buffer_head.h>
38#include <linux/kprobes.h>
39#include <linux/list.h>
40#include <linux/init.h>
41#include <linux/interrupt.h>
42#include <linux/hrtimer.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#define REC_NUM_DEFAULT 10
52
53enum cname {
54	INVALID,
55	INT_HARDWARE_ENTRY,
56	INT_HW_IRQ_EN,
57	INT_TASKLET_ENTRY,
58	FS_DEVRW,
59	MEM_SWAPOUT,
60	TIMERADD,
61	SCSI_DISPATCH_CMD,
62	IDE_CORE_CP,
63	DIRECT,
64};
65
66enum ctype {
67	NONE,
68	PANIC,
69	BUG,
70	EXCEPTION,
71	LOOP,
72	OVERFLOW,
73	CORRUPT_STACK,
74	UNALIGNED_LOAD_STORE_WRITE,
75	OVERWRITE_ALLOCATION,
76	WRITE_AFTER_FREE,
77};
78
79static char* cp_name[] = {
80	"INT_HARDWARE_ENTRY",
81	"INT_HW_IRQ_EN",
82	"INT_TASKLET_ENTRY",
83	"FS_DEVRW",
84	"MEM_SWAPOUT",
85	"TIMERADD",
86	"SCSI_DISPATCH_CMD",
87	"IDE_CORE_CP",
88	"DIRECT",
89};
90
91static char* cp_type[] = {
92	"PANIC",
93	"BUG",
94	"EXCEPTION",
95	"LOOP",
96	"OVERFLOW",
97	"CORRUPT_STACK",
98	"UNALIGNED_LOAD_STORE_WRITE",
99	"OVERWRITE_ALLOCATION",
100	"WRITE_AFTER_FREE",
101};
102
103static struct jprobe lkdtm;
104
105static int lkdtm_parse_commandline(void);
106static void lkdtm_handler(void);
107
108static char* cpoint_name;
109static char* cpoint_type;
110static int cpoint_count = DEFAULT_COUNT;
111static int recur_count = REC_NUM_DEFAULT;
112
113static enum cname cpoint = INVALID;
114static enum ctype cptype = NONE;
115static int count = DEFAULT_COUNT;
116
117module_param(recur_count, int, 0644);
118MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
119				 "default is 10");
120module_param(cpoint_name, charp, 0644);
121MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
122module_param(cpoint_type, charp, 0644);
123MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
124				"hitting the crash point");
125module_param(cpoint_count, int, 0644);
126MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
127				"crash point is to be hit to trigger action");
128
129static unsigned int jp_do_irq(unsigned int irq)
130{
131	lkdtm_handler();
132	jprobe_return();
133	return 0;
134}
135
136static irqreturn_t jp_handle_irq_event(unsigned int irq,
137				       struct irqaction *action)
138{
139	lkdtm_handler();
140	jprobe_return();
141	return 0;
142}
143
144static void jp_tasklet_action(struct softirq_action *a)
145{
146	lkdtm_handler();
147	jprobe_return();
148}
149
150static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
151{
152	lkdtm_handler();
153	jprobe_return();
154}
155
156struct scan_control;
157
158static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
159					     struct zone *zone,
160					     struct scan_control *sc)
161{
162	lkdtm_handler();
163	jprobe_return();
164	return 0;
165}
166
167static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
168			    const enum hrtimer_mode mode)
169{
170	lkdtm_handler();
171	jprobe_return();
172	return 0;
173}
174
175static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
176{
177	lkdtm_handler();
178	jprobe_return();
179	return 0;
180}
181
182#ifdef CONFIG_IDE
183int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
184			struct block_device *bdev, unsigned int cmd,
185			unsigned long arg)
186{
187	lkdtm_handler();
188	jprobe_return();
189	return 0;
190}
191#endif
192
193/* Return the crashpoint number or NONE if the name is invalid */
194static enum ctype parse_cp_type(const char *what, size_t count)
195{
196	int i;
197
198	for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
199		if (!strcmp(what, cp_type[i]))
200			return i + 1;
201	}
202
203	return NONE;
204}
205
206static const char *cp_type_to_str(enum ctype type)
207{
208	if (type == NONE || type < 0 || type > ARRAY_SIZE(cp_type))
209		return "None";
210
211	return cp_type[type - 1];
212}
213
214static const char *cp_name_to_str(enum cname name)
215{
216	if (name == INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
217		return "INVALID";
218
219	return cp_name[name - 1];
220}
221
222
223static int lkdtm_parse_commandline(void)
224{
225	int i;
226
227	if (cpoint_count < 1 || recur_count < 1)
228		return -EINVAL;
229
230	count = cpoint_count;
231
232	/* No special parameters */
233	if (!cpoint_type && !cpoint_name)
234		return 0;
235
236	/* Neither or both of these need to be set */
237	if (!cpoint_type || !cpoint_name)
238		return -EINVAL;
239
240	cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
241	if (cptype == NONE)
242		return -EINVAL;
243
244	for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
245		if (!strcmp(cpoint_name, cp_name[i])) {
246			cpoint = i + 1;
247			return 0;
248		}
249	}
250
251	/* Could not find a valid crash point */
252	return -EINVAL;
253}
254
255static int recursive_loop(int a)
256{
257	char buf[1024];
258
259	memset(buf,0xFF,1024);
260	recur_count--;
261	if (!recur_count)
262		return 0;
263	else
264        	return recursive_loop(a);
265}
266
267static void lkdtm_do_action(enum ctype which)
268{
269	switch (which) {
270	case PANIC:
271		panic("dumptest");
272		break;
273	case BUG:
274		BUG();
275		break;
276	case EXCEPTION:
277		*((int *) 0) = 0;
278		break;
279	case LOOP:
280		for (;;)
281			;
282		break;
283	case OVERFLOW:
284		(void) recursive_loop(0);
285		break;
286	case CORRUPT_STACK: {
287		volatile u32 data[8];
288		volatile u32 *p = data;
289
290		p[12] = 0x12345678;
291		break;
292	}
293	case UNALIGNED_LOAD_STORE_WRITE: {
294		static u8 data[5] __attribute__((aligned(4))) = {1, 2,
295				3, 4, 5};
296		u32 *p;
297		u32 val = 0x12345678;
298
299		p = (u32 *)(data + 1);
300		if (*p == 0)
301			val = 0x87654321;
302		*p = val;
303		 break;
304	}
305	case OVERWRITE_ALLOCATION: {
306		size_t len = 1020;
307		u32 *data = kmalloc(len, GFP_KERNEL);
308
309		data[1024 / sizeof(u32)] = 0x12345678;
310		kfree(data);
311		break;
312	}
313	case WRITE_AFTER_FREE: {
314		size_t len = 1024;
315		u32 *data = kmalloc(len, GFP_KERNEL);
316
317		kfree(data);
318		schedule();
319		memset(data, 0x78, len);
320		break;
321	}
322	case NONE:
323	default:
324		break;
325	}
326
327}
328
329static void lkdtm_handler(void)
330{
331	count--;
332	printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
333			cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
334
335	if (count == 0) {
336		lkdtm_do_action(cptype);
337		count = cpoint_count;
338	}
339}
340
341static int lkdtm_register_cpoint(enum cname which)
342{
343	int ret;
344
345	cpoint = INVALID;
346	if (lkdtm.entry != NULL)
347		unregister_jprobe(&lkdtm);
348
349	switch (which) {
350	case DIRECT:
351		lkdtm_do_action(cptype);
352		return 0;
353	case INT_HARDWARE_ENTRY:
354		lkdtm.kp.symbol_name = "do_IRQ";
355		lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
356		break;
357	case INT_HW_IRQ_EN:
358		lkdtm.kp.symbol_name = "handle_IRQ_event";
359		lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
360		break;
361	case INT_TASKLET_ENTRY:
362		lkdtm.kp.symbol_name = "tasklet_action";
363		lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
364		break;
365	case FS_DEVRW:
366		lkdtm.kp.symbol_name = "ll_rw_block";
367		lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
368		break;
369	case MEM_SWAPOUT:
370		lkdtm.kp.symbol_name = "shrink_inactive_list";
371		lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
372		break;
373	case TIMERADD:
374		lkdtm.kp.symbol_name = "hrtimer_start";
375		lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
376		break;
377	case SCSI_DISPATCH_CMD:
378		lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
379		lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
380		break;
381	case IDE_CORE_CP:
382#ifdef CONFIG_IDE
383		lkdtm.kp.symbol_name = "generic_ide_ioctl";
384		lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
385#else
386		printk(KERN_INFO "lkdtm: Crash point not available\n");
387		return -EINVAL;
388#endif
389		break;
390	default:
391		printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
392		return -EINVAL;
393	}
394
395	cpoint = which;
396	if ((ret = register_jprobe(&lkdtm)) < 0) {
397		printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
398		cpoint = INVALID;
399	}
400
401	return ret;
402}
403
404static ssize_t do_register_entry(enum cname which, struct file *f,
405		const char __user *user_buf, size_t count, loff_t *off)
406{
407	char *buf;
408	int err;
409
410	if (count >= PAGE_SIZE)
411		return -EINVAL;
412
413	buf = (char *)__get_free_page(GFP_KERNEL);
414	if (!buf)
415		return -ENOMEM;
416	if (copy_from_user(buf, user_buf, count)) {
417		free_page((unsigned long) buf);
418		return -EFAULT;
419	}
420	/* NULL-terminate and remove enter */
421	buf[count] = '\0';
422	strim(buf);
423
424	cptype = parse_cp_type(buf, count);
425	free_page((unsigned long) buf);
426
427	if (cptype == NONE)
428		return -EINVAL;
429
430	err = lkdtm_register_cpoint(which);
431	if (err < 0)
432		return err;
433
434	*off += count;
435
436	return count;
437}
438
439/* Generic read callback that just prints out the available crash types */
440static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
441		size_t count, loff_t *off)
442{
443	char *buf;
444	int i, n, out;
445
446	buf = (char *)__get_free_page(GFP_KERNEL);
447
448	n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
449	for (i = 0; i < ARRAY_SIZE(cp_type); i++)
450		n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
451	buf[n] = '\0';
452
453	out = simple_read_from_buffer(user_buf, count, off,
454				      buf, n);
455	free_page((unsigned long) buf);
456
457	return out;
458}
459
460static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
461{
462	return 0;
463}
464
465
466static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
467		size_t count, loff_t *off)
468{
469	return do_register_entry(INT_HARDWARE_ENTRY, f, buf, count, off);
470}
471
472static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
473		size_t count, loff_t *off)
474{
475	return do_register_entry(INT_HW_IRQ_EN, f, buf, count, off);
476}
477
478static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
479		size_t count, loff_t *off)
480{
481	return do_register_entry(INT_TASKLET_ENTRY, f, buf, count, off);
482}
483
484static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
485		size_t count, loff_t *off)
486{
487	return do_register_entry(FS_DEVRW, f, buf, count, off);
488}
489
490static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
491		size_t count, loff_t *off)
492{
493	return do_register_entry(MEM_SWAPOUT, f, buf, count, off);
494}
495
496static ssize_t timeradd_entry(struct file *f, const char __user *buf,
497		size_t count, loff_t *off)
498{
499	return do_register_entry(TIMERADD, f, buf, count, off);
500}
501
502static ssize_t scsi_dispatch_cmd_entry(struct file *f,
503		const char __user *buf, size_t count, loff_t *off)
504{
505	return do_register_entry(SCSI_DISPATCH_CMD, f, buf, count, off);
506}
507
508static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
509		size_t count, loff_t *off)
510{
511	return do_register_entry(IDE_CORE_CP, f, buf, count, off);
512}
513
514/* Special entry to just crash directly. Available without KPROBEs */
515static ssize_t direct_entry(struct file *f, const char __user *user_buf,
516		size_t count, loff_t *off)
517{
518	enum ctype type;
519	char *buf;
520
521	if (count >= PAGE_SIZE)
522		return -EINVAL;
523	if (count < 1)
524		return -EINVAL;
525
526	buf = (char *)__get_free_page(GFP_KERNEL);
527	if (!buf)
528		return -ENOMEM;
529	if (copy_from_user(buf, user_buf, count)) {
530		free_page((unsigned long) buf);
531		return -EFAULT;
532	}
533	/* NULL-terminate and remove enter */
534	buf[count] = '\0';
535	strim(buf);
536
537	type = parse_cp_type(buf, count);
538	free_page((unsigned long) buf);
539	if (type == NONE)
540		return -EINVAL;
541
542	printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
543			cp_type_to_str(type));
544	lkdtm_do_action(type);
545	*off += count;
546
547	return count;
548}
549
550struct crash_entry {
551	const char *name;
552	const struct file_operations fops;
553};
554
555static const struct crash_entry crash_entries[] = {
556	{"DIRECT", {.read = lkdtm_debugfs_read,
557			.open = lkdtm_debugfs_open,
558			.write = direct_entry} },
559	{"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
560			.open = lkdtm_debugfs_open,
561			.write = int_hardware_entry} },
562	{"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
563			.open = lkdtm_debugfs_open,
564			.write = int_hw_irq_en} },
565	{"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
566			.open = lkdtm_debugfs_open,
567			.write = int_tasklet_entry} },
568	{"FS_DEVRW", {.read = lkdtm_debugfs_read,
569			.open = lkdtm_debugfs_open,
570			.write = fs_devrw_entry} },
571	{"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
572			.open = lkdtm_debugfs_open,
573			.write = mem_swapout_entry} },
574	{"TIMERADD", {.read = lkdtm_debugfs_read,
575			.open = lkdtm_debugfs_open,
576			.write = timeradd_entry} },
577	{"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
578			.open = lkdtm_debugfs_open,
579			.write = scsi_dispatch_cmd_entry} },
580	{"IDE_CORE_CP",	{.read = lkdtm_debugfs_read,
581			.open = lkdtm_debugfs_open,
582			.write = ide_core_cp_entry} },
583};
584
585static struct dentry *lkdtm_debugfs_root;
586
587static int __init lkdtm_module_init(void)
588{
589	int ret = -EINVAL;
590	int n_debugfs_entries = 1; /* Assume only the direct entry */
591	int i;
592
593	/* Register debugfs interface */
594	lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
595	if (!lkdtm_debugfs_root) {
596		printk(KERN_ERR "lkdtm: creating root dir failed\n");
597		return -ENODEV;
598	}
599
600#ifdef CONFIG_KPROBES
601	n_debugfs_entries = ARRAY_SIZE(crash_entries);
602#endif
603
604	for (i = 0; i < n_debugfs_entries; i++) {
605		const struct crash_entry *cur = &crash_entries[i];
606		struct dentry *de;
607
608		de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
609				NULL, &cur->fops);
610		if (de == NULL) {
611			printk(KERN_ERR "lkdtm: could not create %s\n",
612					cur->name);
613			goto out_err;
614		}
615	}
616
617	if (lkdtm_parse_commandline() == -EINVAL) {
618		printk(KERN_INFO "lkdtm: Invalid command\n");
619		goto out_err;
620	}
621
622	if (cpoint != INVALID && cptype != NONE) {
623		ret = lkdtm_register_cpoint(cpoint);
624		if (ret < 0) {
625			printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
626					cpoint);
627			goto out_err;
628		}
629		printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
630				cpoint_name, cpoint_type);
631	} else {
632		printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
633	}
634
635	return 0;
636
637out_err:
638	debugfs_remove_recursive(lkdtm_debugfs_root);
639	return ret;
640}
641
642static void __exit lkdtm_module_exit(void)
643{
644	debugfs_remove_recursive(lkdtm_debugfs_root);
645
646	unregister_jprobe(&lkdtm);
647	printk(KERN_INFO "lkdtm: Crash point unregistered\n");
648}
649
650module_init(lkdtm_module_init);
651module_exit(lkdtm_module_exit);
652
653MODULE_LICENSE("GPL");
654