arm64: Drop unneeded stackleak_check_alloca()
[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/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 int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
60 static ssize_t lkdtm_debugfs_entry(struct file *f,
61                                    const char __user *user_buf,
62                                    size_t count, loff_t *off);
63 # define CRASHPOINT_KPROBE(_symbol)                             \
64                 .kprobe = {                                     \
65                         .symbol_name = (_symbol),               \
66                         .pre_handler = lkdtm_kprobe_handler,    \
67                 },
68 # define CRASHPOINT_WRITE(_symbol)                              \
69                 (_symbol) ? lkdtm_debugfs_entry : direct_entry
70 #else
71 # define CRASHPOINT_KPROBE(_symbol)
72 # define CRASHPOINT_WRITE(_symbol)              direct_entry
73 #endif
74
75 /* Crash points */
76 struct crashpoint {
77         const char *name;
78         const struct file_operations fops;
79         struct kprobe kprobe;
80 };
81
82 #define CRASHPOINT(_name, _symbol)                              \
83         {                                                       \
84                 .name = _name,                                  \
85                 .fops = {                                       \
86                         .read   = lkdtm_debugfs_read,           \
87                         .llseek = generic_file_llseek,          \
88                         .open   = lkdtm_debugfs_open,           \
89                         .write  = CRASHPOINT_WRITE(_symbol)     \
90                 },                                              \
91                 CRASHPOINT_KPROBE(_symbol)                      \
92         }
93
94 /* Define the possible places where we can trigger a crash point. */
95 static struct crashpoint crashpoints[] = {
96         CRASHPOINT("DIRECT",             NULL),
97 #ifdef CONFIG_KPROBES
98         CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
99         CRASHPOINT("INT_HW_IRQ_EN",      "handle_irq_event"),
100         CRASHPOINT("INT_TASKLET_ENTRY",  "tasklet_action"),
101         CRASHPOINT("FS_DEVRW",           "ll_rw_block"),
102         CRASHPOINT("MEM_SWAPOUT",        "shrink_inactive_list"),
103         CRASHPOINT("TIMERADD",           "hrtimer_start"),
104         CRASHPOINT("SCSI_DISPATCH_CMD",  "scsi_dispatch_cmd"),
105 # ifdef CONFIG_IDE
106         CRASHPOINT("IDE_CORE_CP",        "generic_ide_ioctl"),
107 # endif
108 #endif
109 };
110
111
112 /* Crash types. */
113 struct crashtype {
114         const char *name;
115         void (*func)(void);
116 };
117
118 #define CRASHTYPE(_name)                        \
119         {                                       \
120                 .name = __stringify(_name),     \
121                 .func = lkdtm_ ## _name,        \
122         }
123
124 /* Define the possible types of crashes that can be triggered. */
125 static const struct crashtype crashtypes[] = {
126         CRASHTYPE(PANIC),
127         CRASHTYPE(BUG),
128         CRASHTYPE(WARNING),
129         CRASHTYPE(EXCEPTION),
130         CRASHTYPE(LOOP),
131         CRASHTYPE(OVERFLOW),
132         CRASHTYPE(CORRUPT_LIST_ADD),
133         CRASHTYPE(CORRUPT_LIST_DEL),
134         CRASHTYPE(CORRUPT_USER_DS),
135         CRASHTYPE(CORRUPT_STACK),
136         CRASHTYPE(CORRUPT_STACK_STRONG),
137         CRASHTYPE(STACK_GUARD_PAGE_LEADING),
138         CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
139         CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
140         CRASHTYPE(OVERWRITE_ALLOCATION),
141         CRASHTYPE(WRITE_AFTER_FREE),
142         CRASHTYPE(READ_AFTER_FREE),
143         CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
144         CRASHTYPE(READ_BUDDY_AFTER_FREE),
145         CRASHTYPE(SOFTLOCKUP),
146         CRASHTYPE(HARDLOCKUP),
147         CRASHTYPE(SPINLOCKUP),
148         CRASHTYPE(HUNG_TASK),
149         CRASHTYPE(EXEC_DATA),
150         CRASHTYPE(EXEC_STACK),
151         CRASHTYPE(EXEC_KMALLOC),
152         CRASHTYPE(EXEC_VMALLOC),
153         CRASHTYPE(EXEC_RODATA),
154         CRASHTYPE(EXEC_USERSPACE),
155         CRASHTYPE(ACCESS_USERSPACE),
156         CRASHTYPE(WRITE_RO),
157         CRASHTYPE(WRITE_RO_AFTER_INIT),
158         CRASHTYPE(WRITE_KERN),
159         CRASHTYPE(REFCOUNT_INC_OVERFLOW),
160         CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
161         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
162         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
163         CRASHTYPE(REFCOUNT_DEC_ZERO),
164         CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
165         CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
166         CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
167         CRASHTYPE(REFCOUNT_INC_ZERO),
168         CRASHTYPE(REFCOUNT_ADD_ZERO),
169         CRASHTYPE(REFCOUNT_INC_SATURATED),
170         CRASHTYPE(REFCOUNT_DEC_SATURATED),
171         CRASHTYPE(REFCOUNT_ADD_SATURATED),
172         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
173         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
174         CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
175         CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
176         CRASHTYPE(REFCOUNT_TIMING),
177         CRASHTYPE(ATOMIC_TIMING),
178         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
179         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
180         CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
181         CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
182         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
183         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
184         CRASHTYPE(USERCOPY_STACK_BEYOND),
185         CRASHTYPE(USERCOPY_KERNEL),
186         CRASHTYPE(STACKLEAK_ERASING),
187 };
188
189
190 /* Global kprobe entry and crashtype. */
191 static struct kprobe *lkdtm_kprobe;
192 static struct crashpoint *lkdtm_crashpoint;
193 static const struct crashtype *lkdtm_crashtype;
194
195 /* Module parameters */
196 static int recur_count = -1;
197 module_param(recur_count, int, 0644);
198 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
199
200 static char* cpoint_name;
201 module_param(cpoint_name, charp, 0444);
202 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
203
204 static char* cpoint_type;
205 module_param(cpoint_type, charp, 0444);
206 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
207                                 "hitting the crash point");
208
209 static int cpoint_count = DEFAULT_COUNT;
210 module_param(cpoint_count, int, 0644);
211 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
212                                 "crash point is to be hit to trigger action");
213
214
215 /* Return the crashtype number or NULL if the name is invalid */
216 static const struct crashtype *find_crashtype(const char *name)
217 {
218         int i;
219
220         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
221                 if (!strcmp(name, crashtypes[i].name))
222                         return &crashtypes[i];
223         }
224
225         return NULL;
226 }
227
228 /*
229  * This is forced noinline just so it distinctly shows up in the stackdump
230  * which makes validation of expected lkdtm crashes easier.
231  */
232 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
233 {
234         if (WARN_ON(!crashtype || !crashtype->func))
235                 return;
236         crashtype->func();
237 }
238
239 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
240                                  const struct crashtype *crashtype)
241 {
242         int ret;
243
244         /* If this doesn't have a symbol, just call immediately. */
245         if (!crashpoint->kprobe.symbol_name) {
246                 lkdtm_do_action(crashtype);
247                 return 0;
248         }
249
250         if (lkdtm_kprobe != NULL)
251                 unregister_kprobe(lkdtm_kprobe);
252
253         lkdtm_crashpoint = crashpoint;
254         lkdtm_crashtype = crashtype;
255         lkdtm_kprobe = &crashpoint->kprobe;
256         ret = register_kprobe(lkdtm_kprobe);
257         if (ret < 0) {
258                 pr_info("Couldn't register kprobe %s\n",
259                         crashpoint->kprobe.symbol_name);
260                 lkdtm_kprobe = NULL;
261                 lkdtm_crashpoint = NULL;
262                 lkdtm_crashtype = NULL;
263         }
264
265         return ret;
266 }
267
268 #ifdef CONFIG_KPROBES
269 /* Global crash counter and spinlock. */
270 static int crash_count = DEFAULT_COUNT;
271 static DEFINE_SPINLOCK(crash_count_lock);
272
273 /* Called by kprobe entry points. */
274 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
275 {
276         unsigned long flags;
277         bool do_it = false;
278
279         if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
280                 return 0;
281
282         spin_lock_irqsave(&crash_count_lock, flags);
283         crash_count--;
284         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
285                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
286
287         if (crash_count == 0) {
288                 do_it = true;
289                 crash_count = cpoint_count;
290         }
291         spin_unlock_irqrestore(&crash_count_lock, flags);
292
293         if (do_it)
294                 lkdtm_do_action(lkdtm_crashtype);
295
296         return 0;
297 }
298
299 static ssize_t lkdtm_debugfs_entry(struct file *f,
300                                    const char __user *user_buf,
301                                    size_t count, loff_t *off)
302 {
303         struct crashpoint *crashpoint = file_inode(f)->i_private;
304         const struct crashtype *crashtype = NULL;
305         char *buf;
306         int err;
307
308         if (count >= PAGE_SIZE)
309                 return -EINVAL;
310
311         buf = (char *)__get_free_page(GFP_KERNEL);
312         if (!buf)
313                 return -ENOMEM;
314         if (copy_from_user(buf, user_buf, count)) {
315                 free_page((unsigned long) buf);
316                 return -EFAULT;
317         }
318         /* NULL-terminate and remove enter */
319         buf[count] = '\0';
320         strim(buf);
321
322         crashtype = find_crashtype(buf);
323         free_page((unsigned long)buf);
324
325         if (!crashtype)
326                 return -EINVAL;
327
328         err = lkdtm_register_cpoint(crashpoint, crashtype);
329         if (err < 0)
330                 return err;
331
332         *off += count;
333
334         return count;
335 }
336 #endif
337
338 /* Generic read callback that just prints out the available crash types */
339 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
340                 size_t count, loff_t *off)
341 {
342         char *buf;
343         int i, n, out;
344
345         buf = (char *)__get_free_page(GFP_KERNEL);
346         if (buf == NULL)
347                 return -ENOMEM;
348
349         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
350         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
351                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
352                               crashtypes[i].name);
353         }
354         buf[n] = '\0';
355
356         out = simple_read_from_buffer(user_buf, count, off,
357                                       buf, n);
358         free_page((unsigned long) buf);
359
360         return out;
361 }
362
363 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
364 {
365         return 0;
366 }
367
368 /* Special entry to just crash directly. Available without KPROBEs */
369 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
370                 size_t count, loff_t *off)
371 {
372         const struct crashtype *crashtype;
373         char *buf;
374
375         if (count >= PAGE_SIZE)
376                 return -EINVAL;
377         if (count < 1)
378                 return -EINVAL;
379
380         buf = (char *)__get_free_page(GFP_KERNEL);
381         if (!buf)
382                 return -ENOMEM;
383         if (copy_from_user(buf, user_buf, count)) {
384                 free_page((unsigned long) buf);
385                 return -EFAULT;
386         }
387         /* NULL-terminate and remove enter */
388         buf[count] = '\0';
389         strim(buf);
390
391         crashtype = find_crashtype(buf);
392         free_page((unsigned long) buf);
393         if (!crashtype)
394                 return -EINVAL;
395
396         pr_info("Performing direct entry %s\n", crashtype->name);
397         lkdtm_do_action(crashtype);
398         *off += count;
399
400         return count;
401 }
402
403 static struct dentry *lkdtm_debugfs_root;
404
405 static int __init lkdtm_module_init(void)
406 {
407         struct crashpoint *crashpoint = NULL;
408         const struct crashtype *crashtype = NULL;
409         int ret = -EINVAL;
410         int i;
411
412         /* Neither or both of these need to be set */
413         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
414                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
415                 return -EINVAL;
416         }
417
418         if (cpoint_type) {
419                 crashtype = find_crashtype(cpoint_type);
420                 if (!crashtype) {
421                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
422                         return -EINVAL;
423                 }
424         }
425
426         if (cpoint_name) {
427                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
428                         if (!strcmp(cpoint_name, crashpoints[i].name))
429                                 crashpoint = &crashpoints[i];
430                 }
431
432                 /* Refuse unknown crashpoints. */
433                 if (!crashpoint) {
434                         pr_err("Invalid crashpoint %s\n", cpoint_name);
435                         return -EINVAL;
436                 }
437         }
438
439 #ifdef CONFIG_KPROBES
440         /* Set crash count. */
441         crash_count = cpoint_count;
442 #endif
443
444         /* Handle test-specific initialization. */
445         lkdtm_bugs_init(&recur_count);
446         lkdtm_perms_init();
447         lkdtm_usercopy_init();
448
449         /* Register debugfs interface */
450         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
451         if (!lkdtm_debugfs_root) {
452                 pr_err("creating root dir failed\n");
453                 return -ENODEV;
454         }
455
456         /* Install debugfs trigger files. */
457         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
458                 struct crashpoint *cur = &crashpoints[i];
459                 struct dentry *de;
460
461                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
462                                          cur, &cur->fops);
463                 if (de == NULL) {
464                         pr_err("could not create crashpoint %s\n", cur->name);
465                         goto out_err;
466                 }
467         }
468
469         /* Install crashpoint if one was selected. */
470         if (crashpoint) {
471                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
472                 if (ret < 0) {
473                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
474                         goto out_err;
475                 }
476                 pr_info("Crash point %s of type %s registered\n",
477                         crashpoint->name, cpoint_type);
478         } else {
479                 pr_info("No crash points registered, enable through debugfs\n");
480         }
481
482         return 0;
483
484 out_err:
485         debugfs_remove_recursive(lkdtm_debugfs_root);
486         return ret;
487 }
488
489 static void __exit lkdtm_module_exit(void)
490 {
491         debugfs_remove_recursive(lkdtm_debugfs_root);
492
493         /* Handle test-specific clean-up. */
494         lkdtm_usercopy_exit();
495
496         if (lkdtm_kprobe != NULL)
497                 unregister_kprobe(lkdtm_kprobe);
498
499         pr_info("Crash point unregistered\n");
500 }
501
502 module_init(lkdtm_module_init);
503 module_exit(lkdtm_module_exit);
504
505 MODULE_LICENSE("GPL");
506 MODULE_DESCRIPTION("Kernel crash testing module");