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 30 #define DEFAULT_COUNT 10 31 32 static int lkdtm_debugfs_open(struct inode *inode, struct file *file); 33 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 34 size_t count, loff_t *off); 35 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 36 size_t count, loff_t *off); 37 38 #ifdef CONFIG_KPROBES 39 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs); 40 static ssize_t lkdtm_debugfs_entry(struct file *f, 41 const char __user *user_buf, 42 size_t count, loff_t *off); 43 # define CRASHPOINT_KPROBE(_symbol) \ 44 .kprobe = { \ 45 .symbol_name = (_symbol), \ 46 .pre_handler = lkdtm_kprobe_handler, \ 47 }, 48 # define CRASHPOINT_WRITE(_symbol) \ 49 (_symbol) ? lkdtm_debugfs_entry : direct_entry 50 #else 51 # define CRASHPOINT_KPROBE(_symbol) 52 # define CRASHPOINT_WRITE(_symbol) direct_entry 53 #endif 54 55 /* Crash points */ 56 struct crashpoint { 57 const char *name; 58 const struct file_operations fops; 59 struct kprobe kprobe; 60 }; 61 62 #define CRASHPOINT(_name, _symbol) \ 63 { \ 64 .name = _name, \ 65 .fops = { \ 66 .read = lkdtm_debugfs_read, \ 67 .llseek = generic_file_llseek, \ 68 .open = lkdtm_debugfs_open, \ 69 .write = CRASHPOINT_WRITE(_symbol) \ 70 }, \ 71 CRASHPOINT_KPROBE(_symbol) \ 72 } 73 74 /* Define the possible places where we can trigger a crash point. */ 75 static struct crashpoint crashpoints[] = { 76 CRASHPOINT("DIRECT", NULL), 77 #ifdef CONFIG_KPROBES 78 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"), 79 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"), 80 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"), 81 CRASHPOINT("FS_DEVRW", "ll_rw_block"), 82 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"), 83 CRASHPOINT("TIMERADD", "hrtimer_start"), 84 CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"), 85 #endif 86 }; 87 88 89 /* Crash types. */ 90 struct crashtype { 91 const char *name; 92 void (*func)(void); 93 }; 94 95 #define CRASHTYPE(_name) \ 96 { \ 97 .name = __stringify(_name), \ 98 .func = lkdtm_ ## _name, \ 99 } 100 101 /* Define the possible types of crashes that can be triggered. */ 102 static const struct crashtype crashtypes[] = { 103 CRASHTYPE(PANIC), 104 CRASHTYPE(BUG), 105 CRASHTYPE(WARNING), 106 CRASHTYPE(WARNING_MESSAGE), 107 CRASHTYPE(EXCEPTION), 108 CRASHTYPE(LOOP), 109 CRASHTYPE(EXHAUST_STACK), 110 CRASHTYPE(CORRUPT_STACK), 111 CRASHTYPE(CORRUPT_STACK_STRONG), 112 CRASHTYPE(REPORT_STACK), 113 CRASHTYPE(CORRUPT_LIST_ADD), 114 CRASHTYPE(CORRUPT_LIST_DEL), 115 CRASHTYPE(STACK_GUARD_PAGE_LEADING), 116 CRASHTYPE(STACK_GUARD_PAGE_TRAILING), 117 CRASHTYPE(UNSET_SMEP), 118 CRASHTYPE(CORRUPT_PAC), 119 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), 120 CRASHTYPE(SLAB_LINEAR_OVERFLOW), 121 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW), 122 CRASHTYPE(WRITE_AFTER_FREE), 123 CRASHTYPE(READ_AFTER_FREE), 124 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 125 CRASHTYPE(READ_BUDDY_AFTER_FREE), 126 CRASHTYPE(SLAB_INIT_ON_ALLOC), 127 CRASHTYPE(BUDDY_INIT_ON_ALLOC), 128 CRASHTYPE(SLAB_FREE_DOUBLE), 129 CRASHTYPE(SLAB_FREE_CROSS), 130 CRASHTYPE(SLAB_FREE_PAGE), 131 CRASHTYPE(SOFTLOCKUP), 132 CRASHTYPE(HARDLOCKUP), 133 CRASHTYPE(SPINLOCKUP), 134 CRASHTYPE(HUNG_TASK), 135 CRASHTYPE(OVERFLOW_SIGNED), 136 CRASHTYPE(OVERFLOW_UNSIGNED), 137 CRASHTYPE(ARRAY_BOUNDS), 138 CRASHTYPE(EXEC_DATA), 139 CRASHTYPE(EXEC_STACK), 140 CRASHTYPE(EXEC_KMALLOC), 141 CRASHTYPE(EXEC_VMALLOC), 142 CRASHTYPE(EXEC_RODATA), 143 CRASHTYPE(EXEC_USERSPACE), 144 CRASHTYPE(EXEC_NULL), 145 CRASHTYPE(ACCESS_USERSPACE), 146 CRASHTYPE(ACCESS_NULL), 147 CRASHTYPE(WRITE_RO), 148 CRASHTYPE(WRITE_RO_AFTER_INIT), 149 CRASHTYPE(WRITE_KERN), 150 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 151 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 152 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 153 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 154 CRASHTYPE(REFCOUNT_DEC_ZERO), 155 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 156 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 157 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 158 CRASHTYPE(REFCOUNT_INC_ZERO), 159 CRASHTYPE(REFCOUNT_ADD_ZERO), 160 CRASHTYPE(REFCOUNT_INC_SATURATED), 161 CRASHTYPE(REFCOUNT_DEC_SATURATED), 162 CRASHTYPE(REFCOUNT_ADD_SATURATED), 163 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 164 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 165 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 166 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 167 CRASHTYPE(REFCOUNT_TIMING), 168 CRASHTYPE(ATOMIC_TIMING), 169 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 170 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 171 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 172 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 173 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 174 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 175 CRASHTYPE(USERCOPY_STACK_BEYOND), 176 CRASHTYPE(USERCOPY_KERNEL), 177 CRASHTYPE(STACKLEAK_ERASING), 178 CRASHTYPE(CFI_FORWARD_PROTO), 179 CRASHTYPE(FORTIFIED_OBJECT), 180 CRASHTYPE(FORTIFIED_SUBOBJECT), 181 CRASHTYPE(FORTIFIED_STRSCPY), 182 CRASHTYPE(DOUBLE_FAULT), 183 #ifdef CONFIG_PPC_BOOK3S_64 184 CRASHTYPE(PPC_SLB_MULTIHIT), 185 #endif 186 }; 187 188 189 /* Global kprobe entry and crashtype. */ 190 static struct kprobe *lkdtm_kprobe; 191 static struct crashpoint *lkdtm_crashpoint; 192 static const struct crashtype *lkdtm_crashtype; 193 194 /* Module parameters */ 195 static int recur_count = -1; 196 module_param(recur_count, int, 0644); 197 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 198 199 static char* cpoint_name; 200 module_param(cpoint_name, charp, 0444); 201 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 202 203 static char* cpoint_type; 204 module_param(cpoint_type, charp, 0444); 205 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 206 "hitting the crash point"); 207 208 static int cpoint_count = DEFAULT_COUNT; 209 module_param(cpoint_count, int, 0644); 210 MODULE_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 */ 215 static 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 */ 231 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 232 { 233 if (WARN_ON(!crashtype || !crashtype->func)) 234 return; 235 crashtype->func(); 236 } 237 238 static 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. */ 269 static int crash_count = DEFAULT_COUNT; 270 static DEFINE_SPINLOCK(crash_count_lock); 271 272 /* Called by kprobe entry points. */ 273 static 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 } 297 298 static 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 */ 338 static 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 = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 349 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 350 n += scnprintf(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 } 361 362 static 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 */ 368 static 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 } 401 402 #ifndef MODULE 403 /* 404 * To avoid needing to export parse_args(), just don't use this code 405 * when LKDTM is built as a module. 406 */ 407 struct check_cmdline_args { 408 const char *param; 409 int value; 410 }; 411 412 static int lkdtm_parse_one(char *param, char *val, 413 const char *unused, void *arg) 414 { 415 struct check_cmdline_args *args = arg; 416 417 /* short circuit if we already found a value. */ 418 if (args->value != -ESRCH) 419 return 0; 420 if (strncmp(param, args->param, strlen(args->param)) == 0) { 421 bool bool_result; 422 int ret; 423 424 ret = kstrtobool(val, &bool_result); 425 if (ret == 0) 426 args->value = bool_result; 427 } 428 return 0; 429 } 430 431 int lkdtm_check_bool_cmdline(const char *param) 432 { 433 char *command_line; 434 struct check_cmdline_args args = { 435 .param = param, 436 .value = -ESRCH, 437 }; 438 439 command_line = kstrdup(saved_command_line, GFP_KERNEL); 440 if (!command_line) 441 return -ENOMEM; 442 443 parse_args("Setting sysctl args", command_line, 444 NULL, 0, -1, -1, &args, lkdtm_parse_one); 445 446 kfree(command_line); 447 448 return args.value; 449 } 450 #endif 451 452 static struct dentry *lkdtm_debugfs_root; 453 454 static int __init lkdtm_module_init(void) 455 { 456 struct crashpoint *crashpoint = NULL; 457 const struct crashtype *crashtype = NULL; 458 int ret; 459 int i; 460 461 /* Neither or both of these need to be set */ 462 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 463 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 464 return -EINVAL; 465 } 466 467 if (cpoint_type) { 468 crashtype = find_crashtype(cpoint_type); 469 if (!crashtype) { 470 pr_err("Unknown crashtype '%s'\n", cpoint_type); 471 return -EINVAL; 472 } 473 } 474 475 if (cpoint_name) { 476 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 477 if (!strcmp(cpoint_name, crashpoints[i].name)) 478 crashpoint = &crashpoints[i]; 479 } 480 481 /* Refuse unknown crashpoints. */ 482 if (!crashpoint) { 483 pr_err("Invalid crashpoint %s\n", cpoint_name); 484 return -EINVAL; 485 } 486 } 487 488 #ifdef CONFIG_KPROBES 489 /* Set crash count. */ 490 crash_count = cpoint_count; 491 #endif 492 493 /* Handle test-specific initialization. */ 494 lkdtm_bugs_init(&recur_count); 495 lkdtm_perms_init(); 496 lkdtm_usercopy_init(); 497 lkdtm_heap_init(); 498 499 /* Register debugfs interface */ 500 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 501 502 /* Install debugfs trigger files. */ 503 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 504 struct crashpoint *cur = &crashpoints[i]; 505 506 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 507 &cur->fops); 508 } 509 510 /* Install crashpoint if one was selected. */ 511 if (crashpoint) { 512 ret = lkdtm_register_cpoint(crashpoint, crashtype); 513 if (ret < 0) { 514 pr_info("Invalid crashpoint %s\n", crashpoint->name); 515 goto out_err; 516 } 517 pr_info("Crash point %s of type %s registered\n", 518 crashpoint->name, cpoint_type); 519 } else { 520 pr_info("No crash points registered, enable through debugfs\n"); 521 } 522 523 return 0; 524 525 out_err: 526 debugfs_remove_recursive(lkdtm_debugfs_root); 527 return ret; 528 } 529 530 static void __exit lkdtm_module_exit(void) 531 { 532 debugfs_remove_recursive(lkdtm_debugfs_root); 533 534 /* Handle test-specific clean-up. */ 535 lkdtm_heap_exit(); 536 lkdtm_usercopy_exit(); 537 538 if (lkdtm_kprobe != NULL) 539 unregister_kprobe(lkdtm_kprobe); 540 541 pr_info("Crash point unregistered\n"); 542 } 543 544 module_init(lkdtm_module_init); 545 module_exit(lkdtm_module_exit); 546 547 MODULE_LICENSE("GPL"); 548 MODULE_DESCRIPTION("Kernel crash testing module"); 549