Merge tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...
[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(USERCOPY_KERNEL_DS),
187         CRASHTYPE(STACKLEAK_ERASING),
188 };
189
190
191 /* Global kprobe entry and crashtype. */
192 static struct kprobe *lkdtm_kprobe;
193 static struct crashpoint *lkdtm_crashpoint;
194 static const struct crashtype *lkdtm_crashtype;
195
196 /* Module parameters */
197 static int recur_count = -1;
198 module_param(recur_count, int, 0644);
199 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
200
201 static char* cpoint_name;
202 module_param(cpoint_name, charp, 0444);
203 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
204
205 static char* cpoint_type;
206 module_param(cpoint_type, charp, 0444);
207 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
208                                 "hitting the crash point");
209
210 static int cpoint_count = DEFAULT_COUNT;
211 module_param(cpoint_count, int, 0644);
212 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
213                                 "crash point is to be hit to trigger action");
214
215
216 /* Return the crashtype number or NULL if the name is invalid */
217 static const struct crashtype *find_crashtype(const char *name)
218 {
219         int i;
220
221         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
222                 if (!strcmp(name, crashtypes[i].name))
223                         return &crashtypes[i];
224         }
225
226         return NULL;
227 }
228
229 /*
230  * This is forced noinline just so it distinctly shows up in the stackdump
231  * which makes validation of expected lkdtm crashes easier.
232  */
233 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
234 {
235         if (WARN_ON(!crashtype || !crashtype->func))
236                 return;
237         crashtype->func();
238 }
239
240 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
241                                  const struct crashtype *crashtype)
242 {
243         int ret;
244
245         /* If this doesn't have a symbol, just call immediately. */
246         if (!crashpoint->kprobe.symbol_name) {
247                 lkdtm_do_action(crashtype);
248                 return 0;
249         }
250
251         if (lkdtm_kprobe != NULL)
252                 unregister_kprobe(lkdtm_kprobe);
253
254         lkdtm_crashpoint = crashpoint;
255         lkdtm_crashtype = crashtype;
256         lkdtm_kprobe = &crashpoint->kprobe;
257         ret = register_kprobe(lkdtm_kprobe);
258         if (ret < 0) {
259                 pr_info("Couldn't register kprobe %s\n",
260                         crashpoint->kprobe.symbol_name);
261                 lkdtm_kprobe = NULL;
262                 lkdtm_crashpoint = NULL;
263                 lkdtm_crashtype = NULL;
264         }
265
266         return ret;
267 }
268
269 #ifdef CONFIG_KPROBES
270 /* Global crash counter and spinlock. */
271 static int crash_count = DEFAULT_COUNT;
272 static DEFINE_SPINLOCK(crash_count_lock);
273
274 /* Called by kprobe entry points. */
275 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
276 {
277         unsigned long flags;
278         bool do_it = false;
279
280         if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
281                 return 0;
282
283         spin_lock_irqsave(&crash_count_lock, flags);
284         crash_count--;
285         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
286                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
287
288         if (crash_count == 0) {
289                 do_it = true;
290                 crash_count = cpoint_count;
291         }
292         spin_unlock_irqrestore(&crash_count_lock, flags);
293
294         if (do_it)
295                 lkdtm_do_action(lkdtm_crashtype);
296
297         return 0;
298 }
299
300 static ssize_t lkdtm_debugfs_entry(struct file *f,
301                                    const char __user *user_buf,
302                                    size_t count, loff_t *off)
303 {
304         struct crashpoint *crashpoint = file_inode(f)->i_private;
305         const struct crashtype *crashtype = NULL;
306         char *buf;
307         int err;
308
309         if (count >= PAGE_SIZE)
310                 return -EINVAL;
311
312         buf = (char *)__get_free_page(GFP_KERNEL);
313         if (!buf)
314                 return -ENOMEM;
315         if (copy_from_user(buf, user_buf, count)) {
316                 free_page((unsigned long) buf);
317                 return -EFAULT;
318         }
319         /* NULL-terminate and remove enter */
320         buf[count] = '\0';
321         strim(buf);
322
323         crashtype = find_crashtype(buf);
324         free_page((unsigned long)buf);
325
326         if (!crashtype)
327                 return -EINVAL;
328
329         err = lkdtm_register_cpoint(crashpoint, crashtype);
330         if (err < 0)
331                 return err;
332
333         *off += count;
334
335         return count;
336 }
337 #endif
338
339 /* Generic read callback that just prints out the available crash types */
340 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
341                 size_t count, loff_t *off)
342 {
343         char *buf;
344         int i, n, out;
345
346         buf = (char *)__get_free_page(GFP_KERNEL);
347         if (buf == NULL)
348                 return -ENOMEM;
349
350         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
351         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
352                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
353                               crashtypes[i].name);
354         }
355         buf[n] = '\0';
356
357         out = simple_read_from_buffer(user_buf, count, off,
358                                       buf, n);
359         free_page((unsigned long) buf);
360
361         return out;
362 }
363
364 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
365 {
366         return 0;
367 }
368
369 /* Special entry to just crash directly. Available without KPROBEs */
370 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
371                 size_t count, loff_t *off)
372 {
373         const struct crashtype *crashtype;
374         char *buf;
375
376         if (count >= PAGE_SIZE)
377                 return -EINVAL;
378         if (count < 1)
379                 return -EINVAL;
380
381         buf = (char *)__get_free_page(GFP_KERNEL);
382         if (!buf)
383                 return -ENOMEM;
384         if (copy_from_user(buf, user_buf, count)) {
385                 free_page((unsigned long) buf);
386                 return -EFAULT;
387         }
388         /* NULL-terminate and remove enter */
389         buf[count] = '\0';
390         strim(buf);
391
392         crashtype = find_crashtype(buf);
393         free_page((unsigned long) buf);
394         if (!crashtype)
395                 return -EINVAL;
396
397         pr_info("Performing direct entry %s\n", crashtype->name);
398         lkdtm_do_action(crashtype);
399         *off += count;
400
401         return count;
402 }
403
404 static struct dentry *lkdtm_debugfs_root;
405
406 static int __init lkdtm_module_init(void)
407 {
408         struct crashpoint *crashpoint = NULL;
409         const struct crashtype *crashtype = NULL;
410         int ret = -EINVAL;
411         int i;
412
413         /* Neither or both of these need to be set */
414         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
415                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
416                 return -EINVAL;
417         }
418
419         if (cpoint_type) {
420                 crashtype = find_crashtype(cpoint_type);
421                 if (!crashtype) {
422                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
423                         return -EINVAL;
424                 }
425         }
426
427         if (cpoint_name) {
428                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
429                         if (!strcmp(cpoint_name, crashpoints[i].name))
430                                 crashpoint = &crashpoints[i];
431                 }
432
433                 /* Refuse unknown crashpoints. */
434                 if (!crashpoint) {
435                         pr_err("Invalid crashpoint %s\n", cpoint_name);
436                         return -EINVAL;
437                 }
438         }
439
440 #ifdef CONFIG_KPROBES
441         /* Set crash count. */
442         crash_count = cpoint_count;
443 #endif
444
445         /* Handle test-specific initialization. */
446         lkdtm_bugs_init(&recur_count);
447         lkdtm_perms_init();
448         lkdtm_usercopy_init();
449
450         /* Register debugfs interface */
451         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
452         if (!lkdtm_debugfs_root) {
453                 pr_err("creating root dir failed\n");
454                 return -ENODEV;
455         }
456
457         /* Install debugfs trigger files. */
458         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
459                 struct crashpoint *cur = &crashpoints[i];
460                 struct dentry *de;
461
462                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
463                                          cur, &cur->fops);
464                 if (de == NULL) {
465                         pr_err("could not create crashpoint %s\n", cur->name);
466                         goto out_err;
467                 }
468         }
469
470         /* Install crashpoint if one was selected. */
471         if (crashpoint) {
472                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
473                 if (ret < 0) {
474                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
475                         goto out_err;
476                 }
477                 pr_info("Crash point %s of type %s registered\n",
478                         crashpoint->name, cpoint_type);
479         } else {
480                 pr_info("No crash points registered, enable through debugfs\n");
481         }
482
483         return 0;
484
485 out_err:
486         debugfs_remove_recursive(lkdtm_debugfs_root);
487         return ret;
488 }
489
490 static void __exit lkdtm_module_exit(void)
491 {
492         debugfs_remove_recursive(lkdtm_debugfs_root);
493
494         /* Handle test-specific clean-up. */
495         lkdtm_usercopy_exit();
496
497         if (lkdtm_kprobe != NULL)
498                 unregister_kprobe(lkdtm_kprobe);
499
500         pr_info("Crash point unregistered\n");
501 }
502
503 module_init(lkdtm_module_init);
504 module_exit(lkdtm_module_exit);
505
506 MODULE_LICENSE("GPL");
507 MODULE_DESCRIPTION("Kernel crash testing module");