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 CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"), 86 #endif 87 }; 88 89 90 /* Crash types. */ 91 struct crashtype { 92 const char *name; 93 void (*func)(void); 94 }; 95 96 #define CRASHTYPE(_name) \ 97 { \ 98 .name = __stringify(_name), \ 99 .func = lkdtm_ ## _name, \ 100 } 101 102 /* Define the possible types of crashes that can be triggered. */ 103 static const struct crashtype crashtypes[] = { 104 CRASHTYPE(PANIC), 105 CRASHTYPE(BUG), 106 CRASHTYPE(WARNING), 107 CRASHTYPE(WARNING_MESSAGE), 108 CRASHTYPE(EXCEPTION), 109 CRASHTYPE(LOOP), 110 CRASHTYPE(EXHAUST_STACK), 111 CRASHTYPE(CORRUPT_STACK), 112 CRASHTYPE(CORRUPT_STACK_STRONG), 113 CRASHTYPE(REPORT_STACK), 114 CRASHTYPE(CORRUPT_LIST_ADD), 115 CRASHTYPE(CORRUPT_LIST_DEL), 116 CRASHTYPE(STACK_GUARD_PAGE_LEADING), 117 CRASHTYPE(STACK_GUARD_PAGE_TRAILING), 118 CRASHTYPE(UNSET_SMEP), 119 CRASHTYPE(CORRUPT_PAC), 120 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), 121 CRASHTYPE(SLAB_LINEAR_OVERFLOW), 122 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW), 123 CRASHTYPE(WRITE_AFTER_FREE), 124 CRASHTYPE(READ_AFTER_FREE), 125 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 126 CRASHTYPE(READ_BUDDY_AFTER_FREE), 127 CRASHTYPE(SLAB_INIT_ON_ALLOC), 128 CRASHTYPE(BUDDY_INIT_ON_ALLOC), 129 CRASHTYPE(SLAB_FREE_DOUBLE), 130 CRASHTYPE(SLAB_FREE_CROSS), 131 CRASHTYPE(SLAB_FREE_PAGE), 132 CRASHTYPE(SOFTLOCKUP), 133 CRASHTYPE(HARDLOCKUP), 134 CRASHTYPE(SPINLOCKUP), 135 CRASHTYPE(HUNG_TASK), 136 CRASHTYPE(OVERFLOW_SIGNED), 137 CRASHTYPE(OVERFLOW_UNSIGNED), 138 CRASHTYPE(ARRAY_BOUNDS), 139 CRASHTYPE(EXEC_DATA), 140 CRASHTYPE(EXEC_STACK), 141 CRASHTYPE(EXEC_KMALLOC), 142 CRASHTYPE(EXEC_VMALLOC), 143 CRASHTYPE(EXEC_RODATA), 144 CRASHTYPE(EXEC_USERSPACE), 145 CRASHTYPE(EXEC_NULL), 146 CRASHTYPE(ACCESS_USERSPACE), 147 CRASHTYPE(ACCESS_NULL), 148 CRASHTYPE(WRITE_RO), 149 CRASHTYPE(WRITE_RO_AFTER_INIT), 150 CRASHTYPE(WRITE_KERN), 151 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 152 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 153 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 154 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 155 CRASHTYPE(REFCOUNT_DEC_ZERO), 156 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 157 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 158 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 159 CRASHTYPE(REFCOUNT_INC_ZERO), 160 CRASHTYPE(REFCOUNT_ADD_ZERO), 161 CRASHTYPE(REFCOUNT_INC_SATURATED), 162 CRASHTYPE(REFCOUNT_DEC_SATURATED), 163 CRASHTYPE(REFCOUNT_ADD_SATURATED), 164 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 165 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 166 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 167 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 168 CRASHTYPE(REFCOUNT_TIMING), 169 CRASHTYPE(ATOMIC_TIMING), 170 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 171 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 172 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 173 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 174 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 175 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 176 CRASHTYPE(USERCOPY_STACK_BEYOND), 177 CRASHTYPE(USERCOPY_KERNEL), 178 CRASHTYPE(STACKLEAK_ERASING), 179 CRASHTYPE(CFI_FORWARD_PROTO), 180 CRASHTYPE(FORTIFIED_OBJECT), 181 CRASHTYPE(FORTIFIED_SUBOBJECT), 182 CRASHTYPE(FORTIFIED_STRSCPY), 183 CRASHTYPE(DOUBLE_FAULT), 184 #ifdef CONFIG_PPC_BOOK3S_64 185 CRASHTYPE(PPC_SLB_MULTIHIT), 186 #endif 187 }; 188 189 190 /* Global kprobe entry and crashtype. */ 191 static struct kprobe *lkdtm_kprobe; 192 static struct crashpoint *lkdtm_crashpoint; 193 static const struct crashtype *lkdtm_crashtype; 194 195 /* Module parameters */ 196 static int recur_count = -1; 197 module_param(recur_count, int, 0644); 198 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 199 200 static char* cpoint_name; 201 module_param(cpoint_name, charp, 0444); 202 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 203 204 static char* cpoint_type; 205 module_param(cpoint_type, charp, 0444); 206 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 207 "hitting the crash point"); 208 209 static int cpoint_count = DEFAULT_COUNT; 210 module_param(cpoint_count, int, 0644); 211 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 212 "crash point is to be hit to trigger action"); 213 214 215 /* Return the crashtype number or NULL if the name is invalid */ 216 static const struct crashtype *find_crashtype(const char *name) 217 { 218 int i; 219 220 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 221 if (!strcmp(name, crashtypes[i].name)) 222 return &crashtypes[i]; 223 } 224 225 return NULL; 226 } 227 228 /* 229 * This is forced noinline just so it distinctly shows up in the stackdump 230 * which makes validation of expected lkdtm crashes easier. 231 */ 232 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 233 { 234 if (WARN_ON(!crashtype || !crashtype->func)) 235 return; 236 crashtype->func(); 237 } 238 239 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 240 const struct crashtype *crashtype) 241 { 242 int ret; 243 244 /* If this doesn't have a symbol, just call immediately. */ 245 if (!crashpoint->kprobe.symbol_name) { 246 lkdtm_do_action(crashtype); 247 return 0; 248 } 249 250 if (lkdtm_kprobe != NULL) 251 unregister_kprobe(lkdtm_kprobe); 252 253 lkdtm_crashpoint = crashpoint; 254 lkdtm_crashtype = crashtype; 255 lkdtm_kprobe = &crashpoint->kprobe; 256 ret = register_kprobe(lkdtm_kprobe); 257 if (ret < 0) { 258 pr_info("Couldn't register kprobe %s\n", 259 crashpoint->kprobe.symbol_name); 260 lkdtm_kprobe = NULL; 261 lkdtm_crashpoint = NULL; 262 lkdtm_crashtype = NULL; 263 } 264 265 return ret; 266 } 267 268 #ifdef CONFIG_KPROBES 269 /* Global crash counter and spinlock. */ 270 static int crash_count = DEFAULT_COUNT; 271 static DEFINE_SPINLOCK(crash_count_lock); 272 273 /* Called by kprobe entry points. */ 274 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 275 { 276 unsigned long flags; 277 bool do_it = false; 278 279 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 280 return 0; 281 282 spin_lock_irqsave(&crash_count_lock, flags); 283 crash_count--; 284 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 285 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 286 287 if (crash_count == 0) { 288 do_it = true; 289 crash_count = cpoint_count; 290 } 291 spin_unlock_irqrestore(&crash_count_lock, flags); 292 293 if (do_it) 294 lkdtm_do_action(lkdtm_crashtype); 295 296 return 0; 297 } 298 299 static ssize_t lkdtm_debugfs_entry(struct file *f, 300 const char __user *user_buf, 301 size_t count, loff_t *off) 302 { 303 struct crashpoint *crashpoint = file_inode(f)->i_private; 304 const struct crashtype *crashtype = NULL; 305 char *buf; 306 int err; 307 308 if (count >= PAGE_SIZE) 309 return -EINVAL; 310 311 buf = (char *)__get_free_page(GFP_KERNEL); 312 if (!buf) 313 return -ENOMEM; 314 if (copy_from_user(buf, user_buf, count)) { 315 free_page((unsigned long) buf); 316 return -EFAULT; 317 } 318 /* NULL-terminate and remove enter */ 319 buf[count] = '\0'; 320 strim(buf); 321 322 crashtype = find_crashtype(buf); 323 free_page((unsigned long)buf); 324 325 if (!crashtype) 326 return -EINVAL; 327 328 err = lkdtm_register_cpoint(crashpoint, crashtype); 329 if (err < 0) 330 return err; 331 332 *off += count; 333 334 return count; 335 } 336 #endif 337 338 /* Generic read callback that just prints out the available crash types */ 339 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 340 size_t count, loff_t *off) 341 { 342 char *buf; 343 int i, n, out; 344 345 buf = (char *)__get_free_page(GFP_KERNEL); 346 if (buf == NULL) 347 return -ENOMEM; 348 349 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 350 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 351 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 352 crashtypes[i].name); 353 } 354 buf[n] = '\0'; 355 356 out = simple_read_from_buffer(user_buf, count, off, 357 buf, n); 358 free_page((unsigned long) buf); 359 360 return out; 361 } 362 363 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 364 { 365 return 0; 366 } 367 368 /* Special entry to just crash directly. Available without KPROBEs */ 369 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 370 size_t count, loff_t *off) 371 { 372 const struct crashtype *crashtype; 373 char *buf; 374 375 if (count >= PAGE_SIZE) 376 return -EINVAL; 377 if (count < 1) 378 return -EINVAL; 379 380 buf = (char *)__get_free_page(GFP_KERNEL); 381 if (!buf) 382 return -ENOMEM; 383 if (copy_from_user(buf, user_buf, count)) { 384 free_page((unsigned long) buf); 385 return -EFAULT; 386 } 387 /* NULL-terminate and remove enter */ 388 buf[count] = '\0'; 389 strim(buf); 390 391 crashtype = find_crashtype(buf); 392 free_page((unsigned long) buf); 393 if (!crashtype) 394 return -EINVAL; 395 396 pr_info("Performing direct entry %s\n", crashtype->name); 397 lkdtm_do_action(crashtype); 398 *off += count; 399 400 return count; 401 } 402 403 #ifndef MODULE 404 /* 405 * To avoid needing to export parse_args(), just don't use this code 406 * when LKDTM is built as a module. 407 */ 408 struct check_cmdline_args { 409 const char *param; 410 int value; 411 }; 412 413 static int lkdtm_parse_one(char *param, char *val, 414 const char *unused, void *arg) 415 { 416 struct check_cmdline_args *args = arg; 417 418 /* short circuit if we already found a value. */ 419 if (args->value != -ESRCH) 420 return 0; 421 if (strncmp(param, args->param, strlen(args->param)) == 0) { 422 bool bool_result; 423 int ret; 424 425 ret = kstrtobool(val, &bool_result); 426 if (ret == 0) 427 args->value = bool_result; 428 } 429 return 0; 430 } 431 432 int lkdtm_check_bool_cmdline(const char *param) 433 { 434 char *command_line; 435 struct check_cmdline_args args = { 436 .param = param, 437 .value = -ESRCH, 438 }; 439 440 command_line = kstrdup(saved_command_line, GFP_KERNEL); 441 if (!command_line) 442 return -ENOMEM; 443 444 parse_args("Setting sysctl args", command_line, 445 NULL, 0, -1, -1, &args, lkdtm_parse_one); 446 447 kfree(command_line); 448 449 return args.value; 450 } 451 #endif 452 453 static struct dentry *lkdtm_debugfs_root; 454 455 static int __init lkdtm_module_init(void) 456 { 457 struct crashpoint *crashpoint = NULL; 458 const struct crashtype *crashtype = NULL; 459 int ret; 460 int i; 461 462 /* Neither or both of these need to be set */ 463 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 464 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 465 return -EINVAL; 466 } 467 468 if (cpoint_type) { 469 crashtype = find_crashtype(cpoint_type); 470 if (!crashtype) { 471 pr_err("Unknown crashtype '%s'\n", cpoint_type); 472 return -EINVAL; 473 } 474 } 475 476 if (cpoint_name) { 477 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 478 if (!strcmp(cpoint_name, crashpoints[i].name)) 479 crashpoint = &crashpoints[i]; 480 } 481 482 /* Refuse unknown crashpoints. */ 483 if (!crashpoint) { 484 pr_err("Invalid crashpoint %s\n", cpoint_name); 485 return -EINVAL; 486 } 487 } 488 489 #ifdef CONFIG_KPROBES 490 /* Set crash count. */ 491 crash_count = cpoint_count; 492 #endif 493 494 /* Handle test-specific initialization. */ 495 lkdtm_bugs_init(&recur_count); 496 lkdtm_perms_init(); 497 lkdtm_usercopy_init(); 498 lkdtm_heap_init(); 499 500 /* Register debugfs interface */ 501 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 502 503 /* Install debugfs trigger files. */ 504 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 505 struct crashpoint *cur = &crashpoints[i]; 506 507 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 508 &cur->fops); 509 } 510 511 /* Install crashpoint if one was selected. */ 512 if (crashpoint) { 513 ret = lkdtm_register_cpoint(crashpoint, crashtype); 514 if (ret < 0) { 515 pr_info("Invalid crashpoint %s\n", crashpoint->name); 516 goto out_err; 517 } 518 pr_info("Crash point %s of type %s registered\n", 519 crashpoint->name, cpoint_type); 520 } else { 521 pr_info("No crash points registered, enable through debugfs\n"); 522 } 523 524 return 0; 525 526 out_err: 527 debugfs_remove_recursive(lkdtm_debugfs_root); 528 return ret; 529 } 530 531 static void __exit lkdtm_module_exit(void) 532 { 533 debugfs_remove_recursive(lkdtm_debugfs_root); 534 535 /* Handle test-specific clean-up. */ 536 lkdtm_heap_exit(); 537 lkdtm_usercopy_exit(); 538 539 if (lkdtm_kprobe != NULL) 540 unregister_kprobe(lkdtm_kprobe); 541 542 pr_info("Crash point unregistered\n"); 543 } 544 545 module_init(lkdtm_module_init); 546 module_exit(lkdtm_module_exit); 547 548 MODULE_LICENSE("GPL"); 549 MODULE_DESCRIPTION("Kernel crash testing module"); 550