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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 <linux/slab.h>
44#include <scsi/scsi_cmnd.h>
45#include <linux/debugfs.h>
46
47#ifdef CONFIG_IDE
48#include <linux/ide.h>
49#endif
50
51#define DEFAULT_COUNT 10
52#define REC_NUM_DEFAULT 10
53
54enum cname {
55 CN_INVALID,
56 CN_INT_HARDWARE_ENTRY,
57 CN_INT_HW_IRQ_EN,
58 CN_INT_TASKLET_ENTRY,
59 CN_FS_DEVRW,
60 CN_MEM_SWAPOUT,
61 CN_TIMERADD,
62 CN_SCSI_DISPATCH_CMD,
63 CN_IDE_CORE_CP,
64 CN_DIRECT,
65};
66
67enum ctype {
68 CT_NONE,
69 CT_PANIC,
70 CT_BUG,
71 CT_EXCEPTION,
72 CT_LOOP,
73 CT_OVERFLOW,
74 CT_CORRUPT_STACK,
75 CT_UNALIGNED_LOAD_STORE_WRITE,
76 CT_OVERWRITE_ALLOCATION,
77 CT_WRITE_AFTER_FREE,
78 CT_SOFTLOCKUP,
79 CT_HARDLOCKUP,
80 CT_HUNG_TASK,
81};
82
83static char* cp_name[] = {
84 "INT_HARDWARE_ENTRY",
85 "INT_HW_IRQ_EN",
86 "INT_TASKLET_ENTRY",
87 "FS_DEVRW",
88 "MEM_SWAPOUT",
89 "TIMERADD",
90 "SCSI_DISPATCH_CMD",
91 "IDE_CORE_CP",
92 "DIRECT",
93};
94
95static char* cp_type[] = {
96 "PANIC",
97 "BUG",
98 "EXCEPTION",
99 "LOOP",
100 "OVERFLOW",
101 "CORRUPT_STACK",
102 "UNALIGNED_LOAD_STORE_WRITE",
103 "OVERWRITE_ALLOCATION",
104 "WRITE_AFTER_FREE",
105 "SOFTLOCKUP",
106 "HARDLOCKUP",
107 "HUNG_TASK",
108};
109
110static struct jprobe lkdtm;
111
112static int lkdtm_parse_commandline(void);
113static void lkdtm_handler(void);
114
115static char* cpoint_name;
116static char* cpoint_type;
117static int cpoint_count = DEFAULT_COUNT;
118static int recur_count = REC_NUM_DEFAULT;
119
120static enum cname cpoint = CN_INVALID;
121static enum ctype cptype = CT_NONE;
122static int count = DEFAULT_COUNT;
123static DEFINE_SPINLOCK(count_lock);
124
125module_param(recur_count, int, 0644);
126MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
127 "default is 10");
128module_param(cpoint_name, charp, 0444);
129MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
130module_param(cpoint_type, charp, 0444);
131MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
132 "hitting the crash point");
133module_param(cpoint_count, int, 0644);
134MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
135 "crash point is to be hit to trigger action");
136
137static unsigned int jp_do_irq(unsigned int irq)
138{
139 lkdtm_handler();
140 jprobe_return();
141 return 0;
142}
143
144static irqreturn_t jp_handle_irq_event(unsigned int irq,
145 struct irqaction *action)
146{
147 lkdtm_handler();
148 jprobe_return();
149 return 0;
150}
151
152static void jp_tasklet_action(struct softirq_action *a)
153{
154 lkdtm_handler();
155 jprobe_return();
156}
157
158static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
159{
160 lkdtm_handler();
161 jprobe_return();
162}
163
164struct scan_control;
165
166static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
167 struct zone *zone,
168 struct scan_control *sc)
169{
170 lkdtm_handler();
171 jprobe_return();
172 return 0;
173}
174
175static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
176 const enum hrtimer_mode mode)
177{
178 lkdtm_handler();
179 jprobe_return();
180 return 0;
181}
182
183static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
184{
185 lkdtm_handler();
186 jprobe_return();
187 return 0;
188}
189
190#ifdef CONFIG_IDE
191int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
192 struct block_device *bdev, unsigned int cmd,
193 unsigned long arg)
194{
195 lkdtm_handler();
196 jprobe_return();
197 return 0;
198}
199#endif
200
201/* Return the crashpoint number or NONE if the name is invalid */
202static enum ctype parse_cp_type(const char *what, size_t count)
203{
204 int i;
205
206 for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
207 if (!strcmp(what, cp_type[i]))
208 return i + 1;
209 }
210
211 return CT_NONE;
212}
213
214static const char *cp_type_to_str(enum ctype type)
215{
216 if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
217 return "None";
218
219 return cp_type[type - 1];
220}
221
222static const char *cp_name_to_str(enum cname name)
223{
224 if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
225 return "INVALID";
226
227 return cp_name[name - 1];
228}
229
230
231static int lkdtm_parse_commandline(void)
232{
233 int i;
234 unsigned long flags;
235
236 if (cpoint_count < 1 || recur_count < 1)
237 return -EINVAL;
238
239 spin_lock_irqsave(&count_lock, flags);
240 count = cpoint_count;
241 spin_unlock_irqrestore(&count_lock, flags);
242
243 /* No special parameters */
244 if (!cpoint_type && !cpoint_name)
245 return 0;
246
247 /* Neither or both of these need to be set */
248 if (!cpoint_type || !cpoint_name)
249 return -EINVAL;
250
251 cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
252 if (cptype == CT_NONE)
253 return -EINVAL;
254
255 for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
256 if (!strcmp(cpoint_name, cp_name[i])) {
257 cpoint = i + 1;
258 return 0;
259 }
260 }
261
262 /* Could not find a valid crash point */
263 return -EINVAL;
264}
265
266static int recursive_loop(int a)
267{
268 char buf[1024];
269
270 memset(buf,0xFF,1024);
271 recur_count--;
272 if (!recur_count)
273 return 0;
274 else
275 return recursive_loop(a);
276}
277
278static void lkdtm_do_action(enum ctype which)
279{
280 switch (which) {
281 case CT_PANIC:
282 panic("dumptest");
283 break;
284 case CT_BUG:
285 BUG();
286 break;
287 case CT_EXCEPTION:
288 *((int *) 0) = 0;
289 break;
290 case CT_LOOP:
291 for (;;)
292 ;
293 break;
294 case CT_OVERFLOW:
295 (void) recursive_loop(0);
296 break;
297 case CT_CORRUPT_STACK: {
298 volatile u32 data[8];
299 volatile u32 *p = data;
300
301 p[12] = 0x12345678;
302 break;
303 }
304 case CT_UNALIGNED_LOAD_STORE_WRITE: {
305 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
306 3, 4, 5};
307 u32 *p;
308 u32 val = 0x12345678;
309
310 p = (u32 *)(data + 1);
311 if (*p == 0)
312 val = 0x87654321;
313 *p = val;
314 break;
315 }
316 case CT_OVERWRITE_ALLOCATION: {
317 size_t len = 1020;
318 u32 *data = kmalloc(len, GFP_KERNEL);
319
320 data[1024 / sizeof(u32)] = 0x12345678;
321 kfree(data);
322 break;
323 }
324 case CT_WRITE_AFTER_FREE: {
325 size_t len = 1024;
326 u32 *data = kmalloc(len, GFP_KERNEL);
327
328 kfree(data);
329 schedule();
330 memset(data, 0x78, len);
331 break;
332 }
333 case CT_SOFTLOCKUP:
334 preempt_disable();
335 for (;;)
336 cpu_relax();
337 break;
338 case CT_HARDLOCKUP:
339 local_irq_disable();
340 for (;;)
341 cpu_relax();
342 break;
343 case CT_HUNG_TASK:
344 set_current_state(TASK_UNINTERRUPTIBLE);
345 schedule();
346 break;
347 case CT_NONE:
348 default:
349 break;
350 }
351
352}
353
354static void lkdtm_handler(void)
355{
356 unsigned long flags;
357 bool do_it = false;
358
359 spin_lock_irqsave(&count_lock, flags);
360 count--;
361 printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
362 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
363
364 if (count == 0) {
365 do_it = true;
366 count = cpoint_count;
367 }
368 spin_unlock_irqrestore(&count_lock, flags);
369
370 if (do_it)
371 lkdtm_do_action(cptype);
372}
373
374static int lkdtm_register_cpoint(enum cname which)
375{
376 int ret;
377
378 cpoint = CN_INVALID;
379 if (lkdtm.entry != NULL)
380 unregister_jprobe(&lkdtm);
381
382 switch (which) {
383 case CN_DIRECT:
384 lkdtm_do_action(cptype);
385 return 0;
386 case CN_INT_HARDWARE_ENTRY:
387 lkdtm.kp.symbol_name = "do_IRQ";
388 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
389 break;
390 case CN_INT_HW_IRQ_EN:
391 lkdtm.kp.symbol_name = "handle_IRQ_event";
392 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
393 break;
394 case CN_INT_TASKLET_ENTRY:
395 lkdtm.kp.symbol_name = "tasklet_action";
396 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
397 break;
398 case CN_FS_DEVRW:
399 lkdtm.kp.symbol_name = "ll_rw_block";
400 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
401 break;
402 case CN_MEM_SWAPOUT:
403 lkdtm.kp.symbol_name = "shrink_inactive_list";
404 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
405 break;
406 case CN_TIMERADD:
407 lkdtm.kp.symbol_name = "hrtimer_start";
408 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
409 break;
410 case CN_SCSI_DISPATCH_CMD:
411 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
412 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
413 break;
414 case CN_IDE_CORE_CP:
415#ifdef CONFIG_IDE
416 lkdtm.kp.symbol_name = "generic_ide_ioctl";
417 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
418#else
419 printk(KERN_INFO "lkdtm: Crash point not available\n");
420 return -EINVAL;
421#endif
422 break;
423 default:
424 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
425 return -EINVAL;
426 }
427
428 cpoint = which;
429 if ((ret = register_jprobe(&lkdtm)) < 0) {
430 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
431 cpoint = CN_INVALID;
432 }
433
434 return ret;
435}
436
437static ssize_t do_register_entry(enum cname which, struct file *f,
438 const char __user *user_buf, size_t count, loff_t *off)
439{
440 char *buf;
441 int err;
442
443 if (count >= PAGE_SIZE)
444 return -EINVAL;
445
446 buf = (char *)__get_free_page(GFP_KERNEL);
447 if (!buf)
448 return -ENOMEM;
449 if (copy_from_user(buf, user_buf, count)) {
450 free_page((unsigned long) buf);
451 return -EFAULT;
452 }
453 /* NULL-terminate and remove enter */
454 buf[count] = '\0';
455 strim(buf);
456
457 cptype = parse_cp_type(buf, count);
458 free_page((unsigned long) buf);
459
460 if (cptype == CT_NONE)
461 return -EINVAL;
462
463 err = lkdtm_register_cpoint(which);
464 if (err < 0)
465 return err;
466
467 *off += count;
468
469 return count;
470}
471
472/* Generic read callback that just prints out the available crash types */
473static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
474 size_t count, loff_t *off)
475{
476 char *buf;
477 int i, n, out;
478
479 buf = (char *)__get_free_page(GFP_KERNEL);
480
481 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
482 for (i = 0; i < ARRAY_SIZE(cp_type); i++)
483 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
484 buf[n] = '\0';
485
486 out = simple_read_from_buffer(user_buf, count, off,
487 buf, n);
488 free_page((unsigned long) buf);
489
490 return out;
491}
492
493static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
494{
495 return 0;
496}
497
498
499static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
500 size_t count, loff_t *off)
501{
502 return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
503}
504
505static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
506 size_t count, loff_t *off)
507{
508 return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
509}
510
511static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
512 size_t count, loff_t *off)
513{
514 return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
515}
516
517static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
518 size_t count, loff_t *off)
519{
520 return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
521}
522
523static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
524 size_t count, loff_t *off)
525{
526 return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
527}
528
529static ssize_t timeradd_entry(struct file *f, const char __user *buf,
530 size_t count, loff_t *off)
531{
532 return do_register_entry(CN_TIMERADD, f, buf, count, off);
533}
534
535static ssize_t scsi_dispatch_cmd_entry(struct file *f,
536 const char __user *buf, size_t count, loff_t *off)
537{
538 return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
539}
540
541static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
542 size_t count, loff_t *off)
543{
544 return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
545}
546
547/* Special entry to just crash directly. Available without KPROBEs */
548static ssize_t direct_entry(struct file *f, const char __user *user_buf,
549 size_t count, loff_t *off)
550{
551 enum ctype type;
552 char *buf;
553
554 if (count >= PAGE_SIZE)
555 return -EINVAL;
556 if (count < 1)
557 return -EINVAL;
558
559 buf = (char *)__get_free_page(GFP_KERNEL);
560 if (!buf)
561 return -ENOMEM;
562 if (copy_from_user(buf, user_buf, count)) {
563 free_page((unsigned long) buf);
564 return -EFAULT;
565 }
566 /* NULL-terminate and remove enter */
567 buf[count] = '\0';
568 strim(buf);
569
570 type = parse_cp_type(buf, count);
571 free_page((unsigned long) buf);
572 if (type == CT_NONE)
573 return -EINVAL;
574
575 printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
576 cp_type_to_str(type));
577 lkdtm_do_action(type);
578 *off += count;
579
580 return count;
581}
582
583struct crash_entry {
584 const char *name;
585 const struct file_operations fops;
586};
587
588static const struct crash_entry crash_entries[] = {
589 {"DIRECT", {.read = lkdtm_debugfs_read,
590 .llseek = generic_file_llseek,
591 .open = lkdtm_debugfs_open,
592 .write = direct_entry} },
593 {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
594 .llseek = generic_file_llseek,
595 .open = lkdtm_debugfs_open,
596 .write = int_hardware_entry} },
597 {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
598 .llseek = generic_file_llseek,
599 .open = lkdtm_debugfs_open,
600 .write = int_hw_irq_en} },
601 {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
602 .llseek = generic_file_llseek,
603 .open = lkdtm_debugfs_open,
604 .write = int_tasklet_entry} },
605 {"FS_DEVRW", {.read = lkdtm_debugfs_read,
606 .llseek = generic_file_llseek,
607 .open = lkdtm_debugfs_open,
608 .write = fs_devrw_entry} },
609 {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
610 .llseek = generic_file_llseek,
611 .open = lkdtm_debugfs_open,
612 .write = mem_swapout_entry} },
613 {"TIMERADD", {.read = lkdtm_debugfs_read,
614 .llseek = generic_file_llseek,
615 .open = lkdtm_debugfs_open,
616 .write = timeradd_entry} },
617 {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
618 .llseek = generic_file_llseek,
619 .open = lkdtm_debugfs_open,
620 .write = scsi_dispatch_cmd_entry} },
621 {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
622 .llseek = generic_file_llseek,
623 .open = lkdtm_debugfs_open,
624 .write = ide_core_cp_entry} },
625};
626
627static struct dentry *lkdtm_debugfs_root;
628
629static int __init lkdtm_module_init(void)
630{
631 int ret = -EINVAL;
632 int n_debugfs_entries = 1; /* Assume only the direct entry */
633 int i;
634
635 /* Register debugfs interface */
636 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
637 if (!lkdtm_debugfs_root) {
638 printk(KERN_ERR "lkdtm: creating root dir failed\n");
639 return -ENODEV;
640 }
641
642#ifdef CONFIG_KPROBES
643 n_debugfs_entries = ARRAY_SIZE(crash_entries);
644#endif
645
646 for (i = 0; i < n_debugfs_entries; i++) {
647 const struct crash_entry *cur = &crash_entries[i];
648 struct dentry *de;
649
650 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
651 NULL, &cur->fops);
652 if (de == NULL) {
653 printk(KERN_ERR "lkdtm: could not create %s\n",
654 cur->name);
655 goto out_err;
656 }
657 }
658
659 if (lkdtm_parse_commandline() == -EINVAL) {
660 printk(KERN_INFO "lkdtm: Invalid command\n");
661 goto out_err;
662 }
663
664 if (cpoint != CN_INVALID && cptype != CT_NONE) {
665 ret = lkdtm_register_cpoint(cpoint);
666 if (ret < 0) {
667 printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
668 cpoint);
669 goto out_err;
670 }
671 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
672 cpoint_name, cpoint_type);
673 } else {
674 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
675 }
676
677 return 0;
678
679out_err:
680 debugfs_remove_recursive(lkdtm_debugfs_root);
681 return ret;
682}
683
684static void __exit lkdtm_module_exit(void)
685{
686 debugfs_remove_recursive(lkdtm_debugfs_root);
687
688 unregister_jprobe(&lkdtm);
689 printk(KERN_INFO "lkdtm: Crash point unregistered\n");
690}
691
692module_init(lkdtm_module_init);
693module_exit(lkdtm_module_exit);
694
695MODULE_LICENSE("GPL");