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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux Kernel Dump Test Module for testing kernel crashes conditions:
4 * induces system failures at predefined crashpoints and under predefined
5 * operational conditions in order to evaluate the reliability of kernel
6 * sanity checking and crash dumps obtained using different dumping
7 * solutions.
8 *
9 * Copyright (C) IBM Corporation, 2006
10 *
11 * Author: Ankita Garg <ankita@in.ibm.com>
12 *
13 * It is adapted from the Linux Kernel Dump Test Tool by
14 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
15 *
16 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
17 *
18 * See Documentation/fault-injection/provoke-crashes.rst for instructions
19 */
20#include "lkdtm.h"
21#include <linux/fs.h>
22#include <linux/module.h>
23#include <linux/buffer_head.h>
24#include <linux/kprobes.h>
25#include <linux/list.h>
26#include <linux/init.h>
27#include <linux/slab.h>
28#include <linux/debugfs.h>
29#include <linux/utsname.h>
30
31#define DEFAULT_COUNT 10
32
33static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
34static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
35 size_t count, loff_t *off);
36static ssize_t direct_entry(struct file *f, const char __user *user_buf,
37 size_t count, loff_t *off);
38
39#ifdef CONFIG_KPROBES
40static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
41static ssize_t lkdtm_debugfs_entry(struct file *f,
42 const char __user *user_buf,
43 size_t count, loff_t *off);
44# define CRASHPOINT_KPROBE(_symbol) \
45 .kprobe = { \
46 .symbol_name = (_symbol), \
47 .pre_handler = lkdtm_kprobe_handler, \
48 },
49# define CRASHPOINT_WRITE(_symbol) \
50 (_symbol) ? lkdtm_debugfs_entry : direct_entry
51#else
52# define CRASHPOINT_KPROBE(_symbol)
53# define CRASHPOINT_WRITE(_symbol) direct_entry
54#endif
55
56/* Crash points */
57struct crashpoint {
58 const char *name;
59 const struct file_operations fops;
60 struct kprobe kprobe;
61};
62
63#define CRASHPOINT(_name, _symbol) \
64 { \
65 .name = _name, \
66 .fops = { \
67 .read = lkdtm_debugfs_read, \
68 .llseek = generic_file_llseek, \
69 .open = lkdtm_debugfs_open, \
70 .write = CRASHPOINT_WRITE(_symbol) \
71 }, \
72 CRASHPOINT_KPROBE(_symbol) \
73 }
74
75/* Define the possible places where we can trigger a crash point. */
76static struct crashpoint crashpoints[] = {
77 CRASHPOINT("DIRECT", NULL),
78#ifdef CONFIG_KPROBES
79 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
80 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
81 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
82 CRASHPOINT("FS_SUBMIT_BH", "submit_bh"),
83 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
84 CRASHPOINT("TIMERADD", "hrtimer_start"),
85 CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"),
86#endif
87};
88
89/* List of possible types for crashes that can be triggered. */
90static const struct crashtype_category *crashtype_categories[] = {
91 &bugs_crashtypes,
92 &heap_crashtypes,
93 &perms_crashtypes,
94 &refcount_crashtypes,
95 &usercopy_crashtypes,
96 &stackleak_crashtypes,
97 &cfi_crashtypes,
98 &fortify_crashtypes,
99#ifdef CONFIG_PPC_64S_HASH_MMU
100 &powerpc_crashtypes,
101#endif
102};
103
104/* Global kprobe entry and crashtype. */
105static struct kprobe *lkdtm_kprobe;
106static struct crashpoint *lkdtm_crashpoint;
107static const struct crashtype *lkdtm_crashtype;
108
109/* Module parameters */
110static int recur_count = -1;
111module_param(recur_count, int, 0644);
112MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
113
114static char* cpoint_name;
115module_param(cpoint_name, charp, 0444);
116MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
117
118static char* cpoint_type;
119module_param(cpoint_type, charp, 0444);
120MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
121 "hitting the crash point");
122
123static int cpoint_count = DEFAULT_COUNT;
124module_param(cpoint_count, int, 0644);
125MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
126 "crash point is to be hit to trigger action");
127
128/*
129 * For test debug reporting when CI systems provide terse summaries.
130 * TODO: Remove this once reasonable reporting exists in most CI systems:
131 * https://lore.kernel.org/lkml/CAHk-=wiFvfkoFixTapvvyPMN9pq5G-+Dys2eSyBa1vzDGAO5+A@mail.gmail.com
132 */
133char *lkdtm_kernel_info;
134
135/* Return the crashtype number or NULL if the name is invalid */
136static const struct crashtype *find_crashtype(const char *name)
137{
138 int cat, idx;
139
140 for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
141 for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
142 struct crashtype *crashtype;
143
144 crashtype = &crashtype_categories[cat]->crashtypes[idx];
145 if (!strcmp(name, crashtype->name))
146 return crashtype;
147 }
148 }
149
150 return NULL;
151}
152
153/*
154 * This is forced noinline just so it distinctly shows up in the stackdump
155 * which makes validation of expected lkdtm crashes easier.
156 *
157 * NOTE: having a valid return value helps prevent the compiler from doing
158 * tail call optimizations and taking this out of the stack trace.
159 */
160static noinline int lkdtm_do_action(const struct crashtype *crashtype)
161{
162 if (WARN_ON(!crashtype || !crashtype->func))
163 return -EINVAL;
164 crashtype->func();
165
166 return 0;
167}
168
169static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
170 const struct crashtype *crashtype)
171{
172 int ret;
173
174 /* If this doesn't have a symbol, just call immediately. */
175 if (!crashpoint->kprobe.symbol_name)
176 return lkdtm_do_action(crashtype);
177
178 if (lkdtm_kprobe != NULL)
179 unregister_kprobe(lkdtm_kprobe);
180
181 lkdtm_crashpoint = crashpoint;
182 lkdtm_crashtype = crashtype;
183 lkdtm_kprobe = &crashpoint->kprobe;
184 ret = register_kprobe(lkdtm_kprobe);
185 if (ret < 0) {
186 pr_info("Couldn't register kprobe %s\n",
187 crashpoint->kprobe.symbol_name);
188 lkdtm_kprobe = NULL;
189 lkdtm_crashpoint = NULL;
190 lkdtm_crashtype = NULL;
191 }
192
193 return ret;
194}
195
196#ifdef CONFIG_KPROBES
197/* Global crash counter and spinlock. */
198static int crash_count = DEFAULT_COUNT;
199static DEFINE_SPINLOCK(crash_count_lock);
200
201/* Called by kprobe entry points. */
202static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
203{
204 unsigned long flags;
205 bool do_it = false;
206
207 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
208 return 0;
209
210 spin_lock_irqsave(&crash_count_lock, flags);
211 crash_count--;
212 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
213 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
214
215 if (crash_count == 0) {
216 do_it = true;
217 crash_count = cpoint_count;
218 }
219 spin_unlock_irqrestore(&crash_count_lock, flags);
220
221 if (do_it)
222 return lkdtm_do_action(lkdtm_crashtype);
223
224 return 0;
225}
226
227static ssize_t lkdtm_debugfs_entry(struct file *f,
228 const char __user *user_buf,
229 size_t count, loff_t *off)
230{
231 struct crashpoint *crashpoint = file_inode(f)->i_private;
232 const struct crashtype *crashtype = NULL;
233 char *buf;
234 int err;
235
236 if (count >= PAGE_SIZE)
237 return -EINVAL;
238
239 buf = (char *)__get_free_page(GFP_KERNEL);
240 if (!buf)
241 return -ENOMEM;
242 if (copy_from_user(buf, user_buf, count)) {
243 free_page((unsigned long) buf);
244 return -EFAULT;
245 }
246 /* NULL-terminate and remove enter */
247 buf[count] = '\0';
248 strim(buf);
249
250 crashtype = find_crashtype(buf);
251 free_page((unsigned long)buf);
252
253 if (!crashtype)
254 return -EINVAL;
255
256 err = lkdtm_register_cpoint(crashpoint, crashtype);
257 if (err < 0)
258 return err;
259
260 *off += count;
261
262 return count;
263}
264#endif
265
266/* Generic read callback that just prints out the available crash types */
267static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
268 size_t count, loff_t *off)
269{
270 int n, cat, idx;
271 ssize_t out;
272 char *buf;
273
274 buf = (char *)__get_free_page(GFP_KERNEL);
275 if (buf == NULL)
276 return -ENOMEM;
277
278 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
279
280 for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
281 for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
282 struct crashtype *crashtype;
283
284 crashtype = &crashtype_categories[cat]->crashtypes[idx];
285 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
286 crashtype->name);
287 }
288 }
289 buf[n] = '\0';
290
291 out = simple_read_from_buffer(user_buf, count, off,
292 buf, n);
293 free_page((unsigned long) buf);
294
295 return out;
296}
297
298static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
299{
300 return 0;
301}
302
303/* Special entry to just crash directly. Available without KPROBEs */
304static ssize_t direct_entry(struct file *f, const char __user *user_buf,
305 size_t count, loff_t *off)
306{
307 const struct crashtype *crashtype;
308 char *buf;
309 int err;
310
311 if (count >= PAGE_SIZE)
312 return -EINVAL;
313 if (count < 1)
314 return -EINVAL;
315
316 buf = (char *)__get_free_page(GFP_KERNEL);
317 if (!buf)
318 return -ENOMEM;
319 if (copy_from_user(buf, user_buf, count)) {
320 free_page((unsigned long) buf);
321 return -EFAULT;
322 }
323 /* NULL-terminate and remove enter */
324 buf[count] = '\0';
325 strim(buf);
326
327 crashtype = find_crashtype(buf);
328 free_page((unsigned long) buf);
329 if (!crashtype)
330 return -EINVAL;
331
332 pr_info("Performing direct entry %s\n", crashtype->name);
333 err = lkdtm_do_action(crashtype);
334 *off += count;
335
336 if (err)
337 return err;
338 return count;
339}
340
341#ifndef MODULE
342/*
343 * To avoid needing to export parse_args(), just don't use this code
344 * when LKDTM is built as a module.
345 */
346struct check_cmdline_args {
347 const char *param;
348 int value;
349};
350
351static int lkdtm_parse_one(char *param, char *val,
352 const char *unused, void *arg)
353{
354 struct check_cmdline_args *args = arg;
355
356 /* short circuit if we already found a value. */
357 if (args->value != -ESRCH)
358 return 0;
359 if (strncmp(param, args->param, strlen(args->param)) == 0) {
360 bool bool_result;
361 int ret;
362
363 ret = kstrtobool(val, &bool_result);
364 if (ret == 0)
365 args->value = bool_result;
366 }
367 return 0;
368}
369
370int lkdtm_check_bool_cmdline(const char *param)
371{
372 char *command_line;
373 struct check_cmdline_args args = {
374 .param = param,
375 .value = -ESRCH,
376 };
377
378 command_line = kstrdup(saved_command_line, GFP_KERNEL);
379 if (!command_line)
380 return -ENOMEM;
381
382 parse_args("Setting sysctl args", command_line,
383 NULL, 0, -1, -1, &args, lkdtm_parse_one);
384
385 kfree(command_line);
386
387 return args.value;
388}
389#endif
390
391static struct dentry *lkdtm_debugfs_root;
392
393static int __init lkdtm_module_init(void)
394{
395 struct crashpoint *crashpoint = NULL;
396 const struct crashtype *crashtype = NULL;
397 int ret;
398 int i;
399
400 /* Neither or both of these need to be set */
401 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
402 pr_err("Need both cpoint_type and cpoint_name or neither\n");
403 return -EINVAL;
404 }
405
406 if (cpoint_type) {
407 crashtype = find_crashtype(cpoint_type);
408 if (!crashtype) {
409 pr_err("Unknown crashtype '%s'\n", cpoint_type);
410 return -EINVAL;
411 }
412 }
413
414 if (cpoint_name) {
415 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
416 if (!strcmp(cpoint_name, crashpoints[i].name))
417 crashpoint = &crashpoints[i];
418 }
419
420 /* Refuse unknown crashpoints. */
421 if (!crashpoint) {
422 pr_err("Invalid crashpoint %s\n", cpoint_name);
423 return -EINVAL;
424 }
425 }
426
427#ifdef CONFIG_KPROBES
428 /* Set crash count. */
429 crash_count = cpoint_count;
430#endif
431
432 /* Common initialization. */
433 lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
434 init_uts_ns.name.release,
435 init_uts_ns.name.machine);
436
437 /* Handle test-specific initialization. */
438 lkdtm_bugs_init(&recur_count);
439 lkdtm_perms_init();
440 lkdtm_usercopy_init();
441 lkdtm_heap_init();
442
443 /* Register debugfs interface */
444 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
445
446 /* Install debugfs trigger files. */
447 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
448 struct crashpoint *cur = &crashpoints[i];
449
450 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
451 &cur->fops);
452 }
453
454 /* Install crashpoint if one was selected. */
455 if (crashpoint) {
456 ret = lkdtm_register_cpoint(crashpoint, crashtype);
457 if (ret < 0) {
458 pr_info("Invalid crashpoint %s\n", crashpoint->name);
459 goto out_err;
460 }
461 pr_info("Crash point %s of type %s registered\n",
462 crashpoint->name, cpoint_type);
463 } else {
464 pr_info("No crash points registered, enable through debugfs\n");
465 }
466
467 return 0;
468
469out_err:
470 debugfs_remove_recursive(lkdtm_debugfs_root);
471 return ret;
472}
473
474static void __exit lkdtm_module_exit(void)
475{
476 debugfs_remove_recursive(lkdtm_debugfs_root);
477
478 /* Handle test-specific clean-up. */
479 lkdtm_heap_exit();
480 lkdtm_usercopy_exit();
481
482 if (lkdtm_kprobe != NULL)
483 unregister_kprobe(lkdtm_kprobe);
484
485 kfree(lkdtm_kernel_info);
486
487 pr_info("Crash point unregistered\n");
488}
489
490module_init(lkdtm_module_init);
491module_exit(lkdtm_module_exit);
492
493MODULE_LICENSE("GPL");
494MODULE_DESCRIPTION("Kernel crash testing module");
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
52static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
53static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
54 size_t count, loff_t *off);
55static ssize_t direct_entry(struct file *f, const char __user *user_buf,
56 size_t count, loff_t *off);
57
58#ifdef CONFIG_KPROBES
59static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
60static 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 */
76struct 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. */
95static 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. */
113struct 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. */
125static 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};
187
188
189/* Global kprobe entry and crashtype. */
190static struct kprobe *lkdtm_kprobe;
191static struct crashpoint *lkdtm_crashpoint;
192static const struct crashtype *lkdtm_crashtype;
193
194/* Module parameters */
195static int recur_count = -1;
196module_param(recur_count, int, 0644);
197MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
198
199static char* cpoint_name;
200module_param(cpoint_name, charp, 0444);
201MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
202
203static char* cpoint_type;
204module_param(cpoint_type, charp, 0444);
205MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
206 "hitting the crash point");
207
208static int cpoint_count = DEFAULT_COUNT;
209module_param(cpoint_count, int, 0644);
210MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
211 "crash point is to be hit to trigger action");
212
213
214/* Return the crashtype number or NULL if the name is invalid */
215static const struct crashtype *find_crashtype(const char *name)
216{
217 int i;
218
219 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
220 if (!strcmp(name, crashtypes[i].name))
221 return &crashtypes[i];
222 }
223
224 return NULL;
225}
226
227/*
228 * This is forced noinline just so it distinctly shows up in the stackdump
229 * which makes validation of expected lkdtm crashes easier.
230 */
231static noinline void lkdtm_do_action(const struct crashtype *crashtype)
232{
233 if (WARN_ON(!crashtype || !crashtype->func))
234 return;
235 crashtype->func();
236}
237
238static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
239 const struct crashtype *crashtype)
240{
241 int ret;
242
243 /* If this doesn't have a symbol, just call immediately. */
244 if (!crashpoint->kprobe.symbol_name) {
245 lkdtm_do_action(crashtype);
246 return 0;
247 }
248
249 if (lkdtm_kprobe != NULL)
250 unregister_kprobe(lkdtm_kprobe);
251
252 lkdtm_crashpoint = crashpoint;
253 lkdtm_crashtype = crashtype;
254 lkdtm_kprobe = &crashpoint->kprobe;
255 ret = register_kprobe(lkdtm_kprobe);
256 if (ret < 0) {
257 pr_info("Couldn't register kprobe %s\n",
258 crashpoint->kprobe.symbol_name);
259 lkdtm_kprobe = NULL;
260 lkdtm_crashpoint = NULL;
261 lkdtm_crashtype = NULL;
262 }
263
264 return ret;
265}
266
267#ifdef CONFIG_KPROBES
268/* Global crash counter and spinlock. */
269static int crash_count = DEFAULT_COUNT;
270static DEFINE_SPINLOCK(crash_count_lock);
271
272/* Called by kprobe entry points. */
273static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
274{
275 unsigned long flags;
276 bool do_it = false;
277
278 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
279 return 0;
280
281 spin_lock_irqsave(&crash_count_lock, flags);
282 crash_count--;
283 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
284 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
285
286 if (crash_count == 0) {
287 do_it = true;
288 crash_count = cpoint_count;
289 }
290 spin_unlock_irqrestore(&crash_count_lock, flags);
291
292 if (do_it)
293 lkdtm_do_action(lkdtm_crashtype);
294
295 return 0;
296}
297
298static ssize_t lkdtm_debugfs_entry(struct file *f,
299 const char __user *user_buf,
300 size_t count, loff_t *off)
301{
302 struct crashpoint *crashpoint = file_inode(f)->i_private;
303 const struct crashtype *crashtype = NULL;
304 char *buf;
305 int err;
306
307 if (count >= PAGE_SIZE)
308 return -EINVAL;
309
310 buf = (char *)__get_free_page(GFP_KERNEL);
311 if (!buf)
312 return -ENOMEM;
313 if (copy_from_user(buf, user_buf, count)) {
314 free_page((unsigned long) buf);
315 return -EFAULT;
316 }
317 /* NULL-terminate and remove enter */
318 buf[count] = '\0';
319 strim(buf);
320
321 crashtype = find_crashtype(buf);
322 free_page((unsigned long)buf);
323
324 if (!crashtype)
325 return -EINVAL;
326
327 err = lkdtm_register_cpoint(crashpoint, crashtype);
328 if (err < 0)
329 return err;
330
331 *off += count;
332
333 return count;
334}
335#endif
336
337/* Generic read callback that just prints out the available crash types */
338static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
339 size_t count, loff_t *off)
340{
341 char *buf;
342 int i, n, out;
343
344 buf = (char *)__get_free_page(GFP_KERNEL);
345 if (buf == NULL)
346 return -ENOMEM;
347
348 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
349 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
350 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
351 crashtypes[i].name);
352 }
353 buf[n] = '\0';
354
355 out = simple_read_from_buffer(user_buf, count, off,
356 buf, n);
357 free_page((unsigned long) buf);
358
359 return out;
360}
361
362static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
363{
364 return 0;
365}
366
367/* Special entry to just crash directly. Available without KPROBEs */
368static ssize_t direct_entry(struct file *f, const char __user *user_buf,
369 size_t count, loff_t *off)
370{
371 const struct crashtype *crashtype;
372 char *buf;
373
374 if (count >= PAGE_SIZE)
375 return -EINVAL;
376 if (count < 1)
377 return -EINVAL;
378
379 buf = (char *)__get_free_page(GFP_KERNEL);
380 if (!buf)
381 return -ENOMEM;
382 if (copy_from_user(buf, user_buf, count)) {
383 free_page((unsigned long) buf);
384 return -EFAULT;
385 }
386 /* NULL-terminate and remove enter */
387 buf[count] = '\0';
388 strim(buf);
389
390 crashtype = find_crashtype(buf);
391 free_page((unsigned long) buf);
392 if (!crashtype)
393 return -EINVAL;
394
395 pr_info("Performing direct entry %s\n", crashtype->name);
396 lkdtm_do_action(crashtype);
397 *off += count;
398
399 return count;
400}
401
402static struct dentry *lkdtm_debugfs_root;
403
404static int __init lkdtm_module_init(void)
405{
406 struct crashpoint *crashpoint = NULL;
407 const struct crashtype *crashtype = NULL;
408 int ret = -EINVAL;
409 int i;
410
411 /* Neither or both of these need to be set */
412 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
413 pr_err("Need both cpoint_type and cpoint_name or neither\n");
414 return -EINVAL;
415 }
416
417 if (cpoint_type) {
418 crashtype = find_crashtype(cpoint_type);
419 if (!crashtype) {
420 pr_err("Unknown crashtype '%s'\n", cpoint_type);
421 return -EINVAL;
422 }
423 }
424
425 if (cpoint_name) {
426 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
427 if (!strcmp(cpoint_name, crashpoints[i].name))
428 crashpoint = &crashpoints[i];
429 }
430
431 /* Refuse unknown crashpoints. */
432 if (!crashpoint) {
433 pr_err("Invalid crashpoint %s\n", cpoint_name);
434 return -EINVAL;
435 }
436 }
437
438#ifdef CONFIG_KPROBES
439 /* Set crash count. */
440 crash_count = cpoint_count;
441#endif
442
443 /* Handle test-specific initialization. */
444 lkdtm_bugs_init(&recur_count);
445 lkdtm_perms_init();
446 lkdtm_usercopy_init();
447
448 /* Register debugfs interface */
449 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
450 if (!lkdtm_debugfs_root) {
451 pr_err("creating root dir failed\n");
452 return -ENODEV;
453 }
454
455 /* Install debugfs trigger files. */
456 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
457 struct crashpoint *cur = &crashpoints[i];
458 struct dentry *de;
459
460 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
461 cur, &cur->fops);
462 if (de == NULL) {
463 pr_err("could not create crashpoint %s\n", cur->name);
464 goto out_err;
465 }
466 }
467
468 /* Install crashpoint if one was selected. */
469 if (crashpoint) {
470 ret = lkdtm_register_cpoint(crashpoint, crashtype);
471 if (ret < 0) {
472 pr_info("Invalid crashpoint %s\n", crashpoint->name);
473 goto out_err;
474 }
475 pr_info("Crash point %s of type %s registered\n",
476 crashpoint->name, cpoint_type);
477 } else {
478 pr_info("No crash points registered, enable through debugfs\n");
479 }
480
481 return 0;
482
483out_err:
484 debugfs_remove_recursive(lkdtm_debugfs_root);
485 return ret;
486}
487
488static void __exit lkdtm_module_exit(void)
489{
490 debugfs_remove_recursive(lkdtm_debugfs_root);
491
492 /* Handle test-specific clean-up. */
493 lkdtm_usercopy_exit();
494
495 if (lkdtm_kprobe != NULL)
496 unregister_kprobe(lkdtm_kprobe);
497
498 pr_info("Crash point unregistered\n");
499}
500
501module_init(lkdtm_module_init);
502module_exit(lkdtm_module_exit);
503
504MODULE_LICENSE("GPL");
505MODULE_DESCRIPTION("Kernel crash testing module");