lkdtm: Do not depend on BLOCK and clean up headers
[muen/linux.git] / drivers / misc / lkdtm / core.c
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/slab.h>
41 #include <linux/debugfs.h>
42
43 #define DEFAULT_COUNT 10
44
45 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
46 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
47                 size_t count, loff_t *off);
48 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
49                             size_t count, loff_t *off);
50
51 #ifdef CONFIG_KPROBES
52 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
53 static ssize_t lkdtm_debugfs_entry(struct file *f,
54                                    const char __user *user_buf,
55                                    size_t count, loff_t *off);
56 # define CRASHPOINT_KPROBE(_symbol)                             \
57                 .kprobe = {                                     \
58                         .symbol_name = (_symbol),               \
59                         .pre_handler = lkdtm_kprobe_handler,    \
60                 },
61 # define CRASHPOINT_WRITE(_symbol)                              \
62                 (_symbol) ? lkdtm_debugfs_entry : direct_entry
63 #else
64 # define CRASHPOINT_KPROBE(_symbol)
65 # define CRASHPOINT_WRITE(_symbol)              direct_entry
66 #endif
67
68 /* Crash points */
69 struct crashpoint {
70         const char *name;
71         const struct file_operations fops;
72         struct kprobe kprobe;
73 };
74
75 #define CRASHPOINT(_name, _symbol)                              \
76         {                                                       \
77                 .name = _name,                                  \
78                 .fops = {                                       \
79                         .read   = lkdtm_debugfs_read,           \
80                         .llseek = generic_file_llseek,          \
81                         .open   = lkdtm_debugfs_open,           \
82                         .write  = CRASHPOINT_WRITE(_symbol)     \
83                 },                                              \
84                 CRASHPOINT_KPROBE(_symbol)                      \
85         }
86
87 /* Define the possible places where we can trigger a crash point. */
88 static struct crashpoint crashpoints[] = {
89         CRASHPOINT("DIRECT",             NULL),
90 #ifdef CONFIG_KPROBES
91         CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
92         CRASHPOINT("INT_HW_IRQ_EN",      "handle_irq_event"),
93         CRASHPOINT("INT_TASKLET_ENTRY",  "tasklet_action"),
94         CRASHPOINT("FS_DEVRW",           "ll_rw_block"),
95         CRASHPOINT("MEM_SWAPOUT",        "shrink_inactive_list"),
96         CRASHPOINT("TIMERADD",           "hrtimer_start"),
97         CRASHPOINT("SCSI_DISPATCH_CMD",  "scsi_dispatch_cmd"),
98         CRASHPOINT("IDE_CORE_CP",        "generic_ide_ioctl"),
99 #endif
100 };
101
102
103 /* Crash types. */
104 struct crashtype {
105         const char *name;
106         void (*func)(void);
107 };
108
109 #define CRASHTYPE(_name)                        \
110         {                                       \
111                 .name = __stringify(_name),     \
112                 .func = lkdtm_ ## _name,        \
113         }
114
115 /* Define the possible types of crashes that can be triggered. */
116 static const struct crashtype crashtypes[] = {
117         CRASHTYPE(PANIC),
118         CRASHTYPE(BUG),
119         CRASHTYPE(WARNING),
120         CRASHTYPE(EXCEPTION),
121         CRASHTYPE(LOOP),
122         CRASHTYPE(OVERFLOW),
123         CRASHTYPE(CORRUPT_LIST_ADD),
124         CRASHTYPE(CORRUPT_LIST_DEL),
125         CRASHTYPE(CORRUPT_USER_DS),
126         CRASHTYPE(CORRUPT_STACK),
127         CRASHTYPE(CORRUPT_STACK_STRONG),
128         CRASHTYPE(STACK_GUARD_PAGE_LEADING),
129         CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
130         CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
131         CRASHTYPE(OVERWRITE_ALLOCATION),
132         CRASHTYPE(WRITE_AFTER_FREE),
133         CRASHTYPE(READ_AFTER_FREE),
134         CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
135         CRASHTYPE(READ_BUDDY_AFTER_FREE),
136         CRASHTYPE(SOFTLOCKUP),
137         CRASHTYPE(HARDLOCKUP),
138         CRASHTYPE(SPINLOCKUP),
139         CRASHTYPE(HUNG_TASK),
140         CRASHTYPE(EXEC_DATA),
141         CRASHTYPE(EXEC_STACK),
142         CRASHTYPE(EXEC_KMALLOC),
143         CRASHTYPE(EXEC_VMALLOC),
144         CRASHTYPE(EXEC_RODATA),
145         CRASHTYPE(EXEC_USERSPACE),
146         CRASHTYPE(ACCESS_USERSPACE),
147         CRASHTYPE(WRITE_RO),
148         CRASHTYPE(WRITE_RO_AFTER_INIT),
149         CRASHTYPE(WRITE_KERN),
150         CRASHTYPE(REFCOUNT_INC_OVERFLOW),
151         CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
152         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
153         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
154         CRASHTYPE(REFCOUNT_DEC_ZERO),
155         CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
156         CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
157         CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
158         CRASHTYPE(REFCOUNT_INC_ZERO),
159         CRASHTYPE(REFCOUNT_ADD_ZERO),
160         CRASHTYPE(REFCOUNT_INC_SATURATED),
161         CRASHTYPE(REFCOUNT_DEC_SATURATED),
162         CRASHTYPE(REFCOUNT_ADD_SATURATED),
163         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
164         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
165         CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
166         CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
167         CRASHTYPE(REFCOUNT_TIMING),
168         CRASHTYPE(ATOMIC_TIMING),
169         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
170         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
171         CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
172         CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
173         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
174         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
175         CRASHTYPE(USERCOPY_STACK_BEYOND),
176         CRASHTYPE(USERCOPY_KERNEL),
177         CRASHTYPE(USERCOPY_KERNEL_DS),
178         CRASHTYPE(STACKLEAK_ERASING),
179 };
180
181
182 /* Global kprobe entry and crashtype. */
183 static struct kprobe *lkdtm_kprobe;
184 static struct crashpoint *lkdtm_crashpoint;
185 static const struct crashtype *lkdtm_crashtype;
186
187 /* Module parameters */
188 static int recur_count = -1;
189 module_param(recur_count, int, 0644);
190 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
191
192 static char* cpoint_name;
193 module_param(cpoint_name, charp, 0444);
194 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
195
196 static char* cpoint_type;
197 module_param(cpoint_type, charp, 0444);
198 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
199                                 "hitting the crash point");
200
201 static int cpoint_count = DEFAULT_COUNT;
202 module_param(cpoint_count, int, 0644);
203 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
204                                 "crash point is to be hit to trigger action");
205
206
207 /* Return the crashtype number or NULL if the name is invalid */
208 static const struct crashtype *find_crashtype(const char *name)
209 {
210         int i;
211
212         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
213                 if (!strcmp(name, crashtypes[i].name))
214                         return &crashtypes[i];
215         }
216
217         return NULL;
218 }
219
220 /*
221  * This is forced noinline just so it distinctly shows up in the stackdump
222  * which makes validation of expected lkdtm crashes easier.
223  */
224 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
225 {
226         if (WARN_ON(!crashtype || !crashtype->func))
227                 return;
228         crashtype->func();
229 }
230
231 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
232                                  const struct crashtype *crashtype)
233 {
234         int ret;
235
236         /* If this doesn't have a symbol, just call immediately. */
237         if (!crashpoint->kprobe.symbol_name) {
238                 lkdtm_do_action(crashtype);
239                 return 0;
240         }
241
242         if (lkdtm_kprobe != NULL)
243                 unregister_kprobe(lkdtm_kprobe);
244
245         lkdtm_crashpoint = crashpoint;
246         lkdtm_crashtype = crashtype;
247         lkdtm_kprobe = &crashpoint->kprobe;
248         ret = register_kprobe(lkdtm_kprobe);
249         if (ret < 0) {
250                 pr_info("Couldn't register kprobe %s\n",
251                         crashpoint->kprobe.symbol_name);
252                 lkdtm_kprobe = NULL;
253                 lkdtm_crashpoint = NULL;
254                 lkdtm_crashtype = NULL;
255         }
256
257         return ret;
258 }
259
260 #ifdef CONFIG_KPROBES
261 /* Global crash counter and spinlock. */
262 static int crash_count = DEFAULT_COUNT;
263 static DEFINE_SPINLOCK(crash_count_lock);
264
265 /* Called by kprobe entry points. */
266 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
267 {
268         unsigned long flags;
269         bool do_it = false;
270
271         if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
272                 return 0;
273
274         spin_lock_irqsave(&crash_count_lock, flags);
275         crash_count--;
276         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
277                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
278
279         if (crash_count == 0) {
280                 do_it = true;
281                 crash_count = cpoint_count;
282         }
283         spin_unlock_irqrestore(&crash_count_lock, flags);
284
285         if (do_it)
286                 lkdtm_do_action(lkdtm_crashtype);
287
288         return 0;
289 }
290
291 static ssize_t lkdtm_debugfs_entry(struct file *f,
292                                    const char __user *user_buf,
293                                    size_t count, loff_t *off)
294 {
295         struct crashpoint *crashpoint = file_inode(f)->i_private;
296         const struct crashtype *crashtype = NULL;
297         char *buf;
298         int err;
299
300         if (count >= PAGE_SIZE)
301                 return -EINVAL;
302
303         buf = (char *)__get_free_page(GFP_KERNEL);
304         if (!buf)
305                 return -ENOMEM;
306         if (copy_from_user(buf, user_buf, count)) {
307                 free_page((unsigned long) buf);
308                 return -EFAULT;
309         }
310         /* NULL-terminate and remove enter */
311         buf[count] = '\0';
312         strim(buf);
313
314         crashtype = find_crashtype(buf);
315         free_page((unsigned long)buf);
316
317         if (!crashtype)
318                 return -EINVAL;
319
320         err = lkdtm_register_cpoint(crashpoint, crashtype);
321         if (err < 0)
322                 return err;
323
324         *off += count;
325
326         return count;
327 }
328 #endif
329
330 /* Generic read callback that just prints out the available crash types */
331 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
332                 size_t count, loff_t *off)
333 {
334         char *buf;
335         int i, n, out;
336
337         buf = (char *)__get_free_page(GFP_KERNEL);
338         if (buf == NULL)
339                 return -ENOMEM;
340
341         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
342         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
343                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
344                               crashtypes[i].name);
345         }
346         buf[n] = '\0';
347
348         out = simple_read_from_buffer(user_buf, count, off,
349                                       buf, n);
350         free_page((unsigned long) buf);
351
352         return out;
353 }
354
355 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
356 {
357         return 0;
358 }
359
360 /* Special entry to just crash directly. Available without KPROBEs */
361 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
362                 size_t count, loff_t *off)
363 {
364         const struct crashtype *crashtype;
365         char *buf;
366
367         if (count >= PAGE_SIZE)
368                 return -EINVAL;
369         if (count < 1)
370                 return -EINVAL;
371
372         buf = (char *)__get_free_page(GFP_KERNEL);
373         if (!buf)
374                 return -ENOMEM;
375         if (copy_from_user(buf, user_buf, count)) {
376                 free_page((unsigned long) buf);
377                 return -EFAULT;
378         }
379         /* NULL-terminate and remove enter */
380         buf[count] = '\0';
381         strim(buf);
382
383         crashtype = find_crashtype(buf);
384         free_page((unsigned long) buf);
385         if (!crashtype)
386                 return -EINVAL;
387
388         pr_info("Performing direct entry %s\n", crashtype->name);
389         lkdtm_do_action(crashtype);
390         *off += count;
391
392         return count;
393 }
394
395 static struct dentry *lkdtm_debugfs_root;
396
397 static int __init lkdtm_module_init(void)
398 {
399         struct crashpoint *crashpoint = NULL;
400         const struct crashtype *crashtype = NULL;
401         int ret = -EINVAL;
402         int i;
403
404         /* Neither or both of these need to be set */
405         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
406                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
407                 return -EINVAL;
408         }
409
410         if (cpoint_type) {
411                 crashtype = find_crashtype(cpoint_type);
412                 if (!crashtype) {
413                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
414                         return -EINVAL;
415                 }
416         }
417
418         if (cpoint_name) {
419                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
420                         if (!strcmp(cpoint_name, crashpoints[i].name))
421                                 crashpoint = &crashpoints[i];
422                 }
423
424                 /* Refuse unknown crashpoints. */
425                 if (!crashpoint) {
426                         pr_err("Invalid crashpoint %s\n", cpoint_name);
427                         return -EINVAL;
428                 }
429         }
430
431 #ifdef CONFIG_KPROBES
432         /* Set crash count. */
433         crash_count = cpoint_count;
434 #endif
435
436         /* Handle test-specific initialization. */
437         lkdtm_bugs_init(&recur_count);
438         lkdtm_perms_init();
439         lkdtm_usercopy_init();
440
441         /* Register debugfs interface */
442         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
443         if (!lkdtm_debugfs_root) {
444                 pr_err("creating root dir failed\n");
445                 return -ENODEV;
446         }
447
448         /* Install debugfs trigger files. */
449         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
450                 struct crashpoint *cur = &crashpoints[i];
451                 struct dentry *de;
452
453                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
454                                          cur, &cur->fops);
455                 if (de == NULL) {
456                         pr_err("could not create crashpoint %s\n", cur->name);
457                         goto out_err;
458                 }
459         }
460
461         /* Install crashpoint if one was selected. */
462         if (crashpoint) {
463                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
464                 if (ret < 0) {
465                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
466                         goto out_err;
467                 }
468                 pr_info("Crash point %s of type %s registered\n",
469                         crashpoint->name, cpoint_type);
470         } else {
471                 pr_info("No crash points registered, enable through debugfs\n");
472         }
473
474         return 0;
475
476 out_err:
477         debugfs_remove_recursive(lkdtm_debugfs_root);
478         return ret;
479 }
480
481 static void __exit lkdtm_module_exit(void)
482 {
483         debugfs_remove_recursive(lkdtm_debugfs_root);
484
485         /* Handle test-specific clean-up. */
486         lkdtm_usercopy_exit();
487
488         if (lkdtm_kprobe != NULL)
489                 unregister_kprobe(lkdtm_kprobe);
490
491         pr_info("Crash point unregistered\n");
492 }
493
494 module_init(lkdtm_module_init);
495 module_exit(lkdtm_module_exit);
496
497 MODULE_LICENSE("GPL");
498 MODULE_DESCRIPTION("Kernel crash testing module");