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/init.h> 30 31 #define DEFAULT_COUNT 10 32 33 static int lkdtm_debugfs_open(struct inode *inode, struct file *file); 34 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 35 size_t count, loff_t *off); 36 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 37 size_t count, loff_t *off); 38 39 #ifdef CONFIG_KPROBES 40 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs); 41 static 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 */ 57 struct 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. */ 76 static 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_DEVRW", "ll_rw_block"), 83 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"), 84 CRASHPOINT("TIMERADD", "hrtimer_start"), 85 CRASHPOINT("SCSI_DISPATCH_CMD", "scsi_dispatch_cmd"), 86 CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"), 87 #endif 88 }; 89 90 91 /* Crash types. */ 92 struct crashtype { 93 const char *name; 94 void (*func)(void); 95 }; 96 97 #define CRASHTYPE(_name) \ 98 { \ 99 .name = __stringify(_name), \ 100 .func = lkdtm_ ## _name, \ 101 } 102 103 /* Define the possible types of crashes that can be triggered. */ 104 static const struct crashtype crashtypes[] = { 105 CRASHTYPE(PANIC), 106 CRASHTYPE(BUG), 107 CRASHTYPE(WARNING), 108 CRASHTYPE(WARNING_MESSAGE), 109 CRASHTYPE(EXCEPTION), 110 CRASHTYPE(LOOP), 111 CRASHTYPE(EXHAUST_STACK), 112 CRASHTYPE(CORRUPT_STACK), 113 CRASHTYPE(CORRUPT_STACK_STRONG), 114 CRASHTYPE(REPORT_STACK), 115 CRASHTYPE(CORRUPT_LIST_ADD), 116 CRASHTYPE(CORRUPT_LIST_DEL), 117 CRASHTYPE(STACK_GUARD_PAGE_LEADING), 118 CRASHTYPE(STACK_GUARD_PAGE_TRAILING), 119 CRASHTYPE(UNSET_SMEP), 120 CRASHTYPE(CORRUPT_PAC), 121 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), 122 CRASHTYPE(FORTIFY_OBJECT), 123 CRASHTYPE(FORTIFY_SUBOBJECT), 124 CRASHTYPE(SLAB_LINEAR_OVERFLOW), 125 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW), 126 CRASHTYPE(WRITE_AFTER_FREE), 127 CRASHTYPE(READ_AFTER_FREE), 128 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 129 CRASHTYPE(READ_BUDDY_AFTER_FREE), 130 CRASHTYPE(SLAB_INIT_ON_ALLOC), 131 CRASHTYPE(BUDDY_INIT_ON_ALLOC), 132 CRASHTYPE(SLAB_FREE_DOUBLE), 133 CRASHTYPE(SLAB_FREE_CROSS), 134 CRASHTYPE(SLAB_FREE_PAGE), 135 CRASHTYPE(SOFTLOCKUP), 136 CRASHTYPE(HARDLOCKUP), 137 CRASHTYPE(SPINLOCKUP), 138 CRASHTYPE(HUNG_TASK), 139 CRASHTYPE(OVERFLOW_SIGNED), 140 CRASHTYPE(OVERFLOW_UNSIGNED), 141 CRASHTYPE(ARRAY_BOUNDS), 142 CRASHTYPE(EXEC_DATA), 143 CRASHTYPE(EXEC_STACK), 144 CRASHTYPE(EXEC_KMALLOC), 145 CRASHTYPE(EXEC_VMALLOC), 146 CRASHTYPE(EXEC_RODATA), 147 CRASHTYPE(EXEC_USERSPACE), 148 CRASHTYPE(EXEC_NULL), 149 CRASHTYPE(ACCESS_USERSPACE), 150 CRASHTYPE(ACCESS_NULL), 151 CRASHTYPE(WRITE_RO), 152 CRASHTYPE(WRITE_RO_AFTER_INIT), 153 CRASHTYPE(WRITE_KERN), 154 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 155 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 156 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 157 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 158 CRASHTYPE(REFCOUNT_DEC_ZERO), 159 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 160 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 161 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 162 CRASHTYPE(REFCOUNT_INC_ZERO), 163 CRASHTYPE(REFCOUNT_ADD_ZERO), 164 CRASHTYPE(REFCOUNT_INC_SATURATED), 165 CRASHTYPE(REFCOUNT_DEC_SATURATED), 166 CRASHTYPE(REFCOUNT_ADD_SATURATED), 167 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 168 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 169 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 170 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 171 CRASHTYPE(REFCOUNT_TIMING), 172 CRASHTYPE(ATOMIC_TIMING), 173 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 174 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 175 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 176 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 177 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 178 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 179 CRASHTYPE(USERCOPY_STACK_BEYOND), 180 CRASHTYPE(USERCOPY_KERNEL), 181 CRASHTYPE(STACKLEAK_ERASING), 182 CRASHTYPE(CFI_FORWARD_PROTO), 183 CRASHTYPE(FORTIFIED_STRSCPY), 184 CRASHTYPE(DOUBLE_FAULT), 185 #ifdef CONFIG_PPC_BOOK3S_64 186 CRASHTYPE(PPC_SLB_MULTIHIT), 187 #endif 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 = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 351 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 352 n += scnprintf(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 #ifndef MODULE 405 /* 406 * To avoid needing to export parse_args(), just don't use this code 407 * when LKDTM is built as a module. 408 */ 409 struct check_cmdline_args { 410 const char *param; 411 int value; 412 }; 413 414 static int lkdtm_parse_one(char *param, char *val, 415 const char *unused, void *arg) 416 { 417 struct check_cmdline_args *args = arg; 418 419 /* short circuit if we already found a value. */ 420 if (args->value != -ESRCH) 421 return 0; 422 if (strncmp(param, args->param, strlen(args->param)) == 0) { 423 bool bool_result; 424 int ret; 425 426 ret = kstrtobool(val, &bool_result); 427 if (ret == 0) 428 args->value = bool_result; 429 } 430 return 0; 431 } 432 433 int lkdtm_check_bool_cmdline(const char *param) 434 { 435 char *command_line; 436 struct check_cmdline_args args = { 437 .param = param, 438 .value = -ESRCH, 439 }; 440 441 command_line = kstrdup(saved_command_line, GFP_KERNEL); 442 if (!command_line) 443 return -ENOMEM; 444 445 parse_args("Setting sysctl args", command_line, 446 NULL, 0, -1, -1, &args, lkdtm_parse_one); 447 448 kfree(command_line); 449 450 return args.value; 451 } 452 #endif 453 454 static struct dentry *lkdtm_debugfs_root; 455 456 static int __init lkdtm_module_init(void) 457 { 458 struct crashpoint *crashpoint = NULL; 459 const struct crashtype *crashtype = NULL; 460 int ret; 461 int i; 462 463 /* Neither or both of these need to be set */ 464 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 465 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 466 return -EINVAL; 467 } 468 469 if (cpoint_type) { 470 crashtype = find_crashtype(cpoint_type); 471 if (!crashtype) { 472 pr_err("Unknown crashtype '%s'\n", cpoint_type); 473 return -EINVAL; 474 } 475 } 476 477 if (cpoint_name) { 478 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 479 if (!strcmp(cpoint_name, crashpoints[i].name)) 480 crashpoint = &crashpoints[i]; 481 } 482 483 /* Refuse unknown crashpoints. */ 484 if (!crashpoint) { 485 pr_err("Invalid crashpoint %s\n", cpoint_name); 486 return -EINVAL; 487 } 488 } 489 490 #ifdef CONFIG_KPROBES 491 /* Set crash count. */ 492 crash_count = cpoint_count; 493 #endif 494 495 /* Handle test-specific initialization. */ 496 lkdtm_bugs_init(&recur_count); 497 lkdtm_perms_init(); 498 lkdtm_usercopy_init(); 499 lkdtm_heap_init(); 500 501 /* Register debugfs interface */ 502 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 503 504 /* Install debugfs trigger files. */ 505 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 506 struct crashpoint *cur = &crashpoints[i]; 507 508 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 509 &cur->fops); 510 } 511 512 /* Install crashpoint if one was selected. */ 513 if (crashpoint) { 514 ret = lkdtm_register_cpoint(crashpoint, crashtype); 515 if (ret < 0) { 516 pr_info("Invalid crashpoint %s\n", crashpoint->name); 517 goto out_err; 518 } 519 pr_info("Crash point %s of type %s registered\n", 520 crashpoint->name, cpoint_type); 521 } else { 522 pr_info("No crash points registered, enable through debugfs\n"); 523 } 524 525 return 0; 526 527 out_err: 528 debugfs_remove_recursive(lkdtm_debugfs_root); 529 return ret; 530 } 531 532 static void __exit lkdtm_module_exit(void) 533 { 534 debugfs_remove_recursive(lkdtm_debugfs_root); 535 536 /* Handle test-specific clean-up. */ 537 lkdtm_heap_exit(); 538 lkdtm_usercopy_exit(); 539 540 if (lkdtm_kprobe != NULL) 541 unregister_kprobe(lkdtm_kprobe); 542 543 pr_info("Crash point unregistered\n"); 544 } 545 546 module_init(lkdtm_module_init); 547 module_exit(lkdtm_module_exit); 548 549 MODULE_LICENSE("GPL"); 550 MODULE_DESCRIPTION("Kernel crash testing module"); 551