lkdtm: add debugfs access and loosen KPROBE ties
[linux-2.6.git] / drivers / misc / lkdtm.c
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
53 enum 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
66 enum 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
79 static 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
91 static 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
103 static struct jprobe lkdtm;
104
105 static int lkdtm_parse_commandline(void);
106 static void lkdtm_handler(void);
107
108 static char* cpoint_name;
109 static char* cpoint_type;
110 static int cpoint_count = DEFAULT_COUNT;
111 static int recur_count = REC_NUM_DEFAULT;
112
113 static enum cname cpoint = INVALID;
114 static enum ctype cptype = NONE;
115 static int count = DEFAULT_COUNT;
116
117 module_param(recur_count, int, 0644);
118 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
119                                  "default is 10");
120 module_param(cpoint_name, charp, 0644);
121 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
122 module_param(cpoint_type, charp, 0644);
123 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
124                                 "hitting the crash point");
125 module_param(cpoint_count, int, 0644);
126 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
127                                 "crash point is to be hit to trigger action");
128
129 static unsigned int jp_do_irq(unsigned int irq)
130 {
131         lkdtm_handler();
132         jprobe_return();
133         return 0;
134 }
135
136 static 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
144 static void jp_tasklet_action(struct softirq_action *a)
145 {
146         lkdtm_handler();
147         jprobe_return();
148 }
149
150 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
151 {
152         lkdtm_handler();
153         jprobe_return();
154 }
155
156 struct scan_control;
157
158 static 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
167 static 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
175 static 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
183 int 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 */
194 static 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
206 static 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
214 static 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
223 static 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
255 static 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
267 static 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
329 static 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
341 static 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
404 static 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 */
440 static 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
460 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
461 {
462         return 0;
463 }
464
465
466 static 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
472 static 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
478 static 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
484 static 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
490 static 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
496 static 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
502 static 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
508 static 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 */
515 static 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
550 struct crash_entry {
551         const char *name;
552         const struct file_operations fops;
553 };
554
555 static 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
585 static struct dentry *lkdtm_debugfs_root;
586
587 static 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
637 out_err:
638         debugfs_remove_recursive(lkdtm_debugfs_root);
639         return ret;
640 }
641
642 static 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
650 module_init(lkdtm_module_init);
651 module_exit(lkdtm_module_exit);
652
653 MODULE_LICENSE("GPL");