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(EXEC_NULL), 147 CRASHTYPE(ACCESS_USERSPACE), 148 CRASHTYPE(ACCESS_NULL), 149 CRASHTYPE(WRITE_RO), 150 CRASHTYPE(WRITE_RO_AFTER_INIT), 151 CRASHTYPE(WRITE_KERN), 152 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 153 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 154 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 155 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 156 CRASHTYPE(REFCOUNT_DEC_ZERO), 157 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 158 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 159 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 160 CRASHTYPE(REFCOUNT_INC_ZERO), 161 CRASHTYPE(REFCOUNT_ADD_ZERO), 162 CRASHTYPE(REFCOUNT_INC_SATURATED), 163 CRASHTYPE(REFCOUNT_DEC_SATURATED), 164 CRASHTYPE(REFCOUNT_ADD_SATURATED), 165 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 166 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 167 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 168 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 169 CRASHTYPE(REFCOUNT_TIMING), 170 CRASHTYPE(ATOMIC_TIMING), 171 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 172 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 173 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 174 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 175 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 176 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 177 CRASHTYPE(USERCOPY_STACK_BEYOND), 178 CRASHTYPE(USERCOPY_KERNEL), 179 CRASHTYPE(USERCOPY_KERNEL_DS), 180 CRASHTYPE(STACKLEAK_ERASING), 181 }; 182 183 184 /* Global kprobe entry and crashtype. */ 185 static struct kprobe *lkdtm_kprobe; 186 static struct crashpoint *lkdtm_crashpoint; 187 static const struct crashtype *lkdtm_crashtype; 188 189 /* Module parameters */ 190 static int recur_count = -1; 191 module_param(recur_count, int, 0644); 192 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 193 194 static char* cpoint_name; 195 module_param(cpoint_name, charp, 0444); 196 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 197 198 static char* cpoint_type; 199 module_param(cpoint_type, charp, 0444); 200 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 201 "hitting the crash point"); 202 203 static int cpoint_count = DEFAULT_COUNT; 204 module_param(cpoint_count, int, 0644); 205 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 206 "crash point is to be hit to trigger action"); 207 208 209 /* Return the crashtype number or NULL if the name is invalid */ 210 static const struct crashtype *find_crashtype(const char *name) 211 { 212 int i; 213 214 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 215 if (!strcmp(name, crashtypes[i].name)) 216 return &crashtypes[i]; 217 } 218 219 return NULL; 220 } 221 222 /* 223 * This is forced noinline just so it distinctly shows up in the stackdump 224 * which makes validation of expected lkdtm crashes easier. 225 */ 226 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 227 { 228 if (WARN_ON(!crashtype || !crashtype->func)) 229 return; 230 crashtype->func(); 231 } 232 233 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 234 const struct crashtype *crashtype) 235 { 236 int ret; 237 238 /* If this doesn't have a symbol, just call immediately. */ 239 if (!crashpoint->kprobe.symbol_name) { 240 lkdtm_do_action(crashtype); 241 return 0; 242 } 243 244 if (lkdtm_kprobe != NULL) 245 unregister_kprobe(lkdtm_kprobe); 246 247 lkdtm_crashpoint = crashpoint; 248 lkdtm_crashtype = crashtype; 249 lkdtm_kprobe = &crashpoint->kprobe; 250 ret = register_kprobe(lkdtm_kprobe); 251 if (ret < 0) { 252 pr_info("Couldn't register kprobe %s\n", 253 crashpoint->kprobe.symbol_name); 254 lkdtm_kprobe = NULL; 255 lkdtm_crashpoint = NULL; 256 lkdtm_crashtype = NULL; 257 } 258 259 return ret; 260 } 261 262 #ifdef CONFIG_KPROBES 263 /* Global crash counter and spinlock. */ 264 static int crash_count = DEFAULT_COUNT; 265 static DEFINE_SPINLOCK(crash_count_lock); 266 267 /* Called by kprobe entry points. */ 268 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 269 { 270 unsigned long flags; 271 bool do_it = false; 272 273 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 274 return 0; 275 276 spin_lock_irqsave(&crash_count_lock, flags); 277 crash_count--; 278 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 279 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 280 281 if (crash_count == 0) { 282 do_it = true; 283 crash_count = cpoint_count; 284 } 285 spin_unlock_irqrestore(&crash_count_lock, flags); 286 287 if (do_it) 288 lkdtm_do_action(lkdtm_crashtype); 289 290 return 0; 291 } 292 293 static ssize_t lkdtm_debugfs_entry(struct file *f, 294 const char __user *user_buf, 295 size_t count, loff_t *off) 296 { 297 struct crashpoint *crashpoint = file_inode(f)->i_private; 298 const struct crashtype *crashtype = NULL; 299 char *buf; 300 int err; 301 302 if (count >= PAGE_SIZE) 303 return -EINVAL; 304 305 buf = (char *)__get_free_page(GFP_KERNEL); 306 if (!buf) 307 return -ENOMEM; 308 if (copy_from_user(buf, user_buf, count)) { 309 free_page((unsigned long) buf); 310 return -EFAULT; 311 } 312 /* NULL-terminate and remove enter */ 313 buf[count] = '\0'; 314 strim(buf); 315 316 crashtype = find_crashtype(buf); 317 free_page((unsigned long)buf); 318 319 if (!crashtype) 320 return -EINVAL; 321 322 err = lkdtm_register_cpoint(crashpoint, crashtype); 323 if (err < 0) 324 return err; 325 326 *off += count; 327 328 return count; 329 } 330 #endif 331 332 /* Generic read callback that just prints out the available crash types */ 333 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 334 size_t count, loff_t *off) 335 { 336 char *buf; 337 int i, n, out; 338 339 buf = (char *)__get_free_page(GFP_KERNEL); 340 if (buf == NULL) 341 return -ENOMEM; 342 343 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 344 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 345 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 346 crashtypes[i].name); 347 } 348 buf[n] = '\0'; 349 350 out = simple_read_from_buffer(user_buf, count, off, 351 buf, n); 352 free_page((unsigned long) buf); 353 354 return out; 355 } 356 357 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 358 { 359 return 0; 360 } 361 362 /* Special entry to just crash directly. Available without KPROBEs */ 363 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 364 size_t count, loff_t *off) 365 { 366 const struct crashtype *crashtype; 367 char *buf; 368 369 if (count >= PAGE_SIZE) 370 return -EINVAL; 371 if (count < 1) 372 return -EINVAL; 373 374 buf = (char *)__get_free_page(GFP_KERNEL); 375 if (!buf) 376 return -ENOMEM; 377 if (copy_from_user(buf, user_buf, count)) { 378 free_page((unsigned long) buf); 379 return -EFAULT; 380 } 381 /* NULL-terminate and remove enter */ 382 buf[count] = '\0'; 383 strim(buf); 384 385 crashtype = find_crashtype(buf); 386 free_page((unsigned long) buf); 387 if (!crashtype) 388 return -EINVAL; 389 390 pr_info("Performing direct entry %s\n", crashtype->name); 391 lkdtm_do_action(crashtype); 392 *off += count; 393 394 return count; 395 } 396 397 static struct dentry *lkdtm_debugfs_root; 398 399 static int __init lkdtm_module_init(void) 400 { 401 struct crashpoint *crashpoint = NULL; 402 const struct crashtype *crashtype = NULL; 403 int ret = -EINVAL; 404 int i; 405 406 /* Neither or both of these need to be set */ 407 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 408 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 409 return -EINVAL; 410 } 411 412 if (cpoint_type) { 413 crashtype = find_crashtype(cpoint_type); 414 if (!crashtype) { 415 pr_err("Unknown crashtype '%s'\n", cpoint_type); 416 return -EINVAL; 417 } 418 } 419 420 if (cpoint_name) { 421 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 422 if (!strcmp(cpoint_name, crashpoints[i].name)) 423 crashpoint = &crashpoints[i]; 424 } 425 426 /* Refuse unknown crashpoints. */ 427 if (!crashpoint) { 428 pr_err("Invalid crashpoint %s\n", cpoint_name); 429 return -EINVAL; 430 } 431 } 432 433 #ifdef CONFIG_KPROBES 434 /* Set crash count. */ 435 crash_count = cpoint_count; 436 #endif 437 438 /* Handle test-specific initialization. */ 439 lkdtm_bugs_init(&recur_count); 440 lkdtm_perms_init(); 441 lkdtm_usercopy_init(); 442 443 /* Register debugfs interface */ 444 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 445 if (!lkdtm_debugfs_root) { 446 pr_err("creating root dir failed\n"); 447 return -ENODEV; 448 } 449 450 /* Install debugfs trigger files. */ 451 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 452 struct crashpoint *cur = &crashpoints[i]; 453 struct dentry *de; 454 455 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, 456 cur, &cur->fops); 457 if (de == NULL) { 458 pr_err("could not create crashpoint %s\n", cur->name); 459 goto out_err; 460 } 461 } 462 463 /* Install crashpoint if one was selected. */ 464 if (crashpoint) { 465 ret = lkdtm_register_cpoint(crashpoint, crashtype); 466 if (ret < 0) { 467 pr_info("Invalid crashpoint %s\n", crashpoint->name); 468 goto out_err; 469 } 470 pr_info("Crash point %s of type %s registered\n", 471 crashpoint->name, cpoint_type); 472 } else { 473 pr_info("No crash points registered, enable through debugfs\n"); 474 } 475 476 return 0; 477 478 out_err: 479 debugfs_remove_recursive(lkdtm_debugfs_root); 480 return ret; 481 } 482 483 static void __exit lkdtm_module_exit(void) 484 { 485 debugfs_remove_recursive(lkdtm_debugfs_root); 486 487 /* Handle test-specific clean-up. */ 488 lkdtm_usercopy_exit(); 489 490 if (lkdtm_kprobe != NULL) 491 unregister_kprobe(lkdtm_kprobe); 492 493 pr_info("Crash point unregistered\n"); 494 } 495 496 module_init(lkdtm_module_init); 497 module_exit(lkdtm_module_exit); 498 499 MODULE_LICENSE("GPL"); 500 MODULE_DESCRIPTION("Kernel crash testing module"); 501