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"); 508