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/utsname.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_QUEUE_RQ", "scsi_queue_rq"), 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 /* For test debug reporting. */ 215 char *lkdtm_kernel_info; 216 217 /* Return the crashtype number or NULL if the name is invalid */ 218 static const struct crashtype *find_crashtype(const char *name) 219 { 220 int i; 221 222 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 223 if (!strcmp(name, crashtypes[i].name)) 224 return &crashtypes[i]; 225 } 226 227 return NULL; 228 } 229 230 /* 231 * This is forced noinline just so it distinctly shows up in the stackdump 232 * which makes validation of expected lkdtm crashes easier. 233 */ 234 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 235 { 236 if (WARN_ON(!crashtype || !crashtype->func)) 237 return; 238 crashtype->func(); 239 } 240 241 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 242 const struct crashtype *crashtype) 243 { 244 int ret; 245 246 /* If this doesn't have a symbol, just call immediately. */ 247 if (!crashpoint->kprobe.symbol_name) { 248 lkdtm_do_action(crashtype); 249 return 0; 250 } 251 252 if (lkdtm_kprobe != NULL) 253 unregister_kprobe(lkdtm_kprobe); 254 255 lkdtm_crashpoint = crashpoint; 256 lkdtm_crashtype = crashtype; 257 lkdtm_kprobe = &crashpoint->kprobe; 258 ret = register_kprobe(lkdtm_kprobe); 259 if (ret < 0) { 260 pr_info("Couldn't register kprobe %s\n", 261 crashpoint->kprobe.symbol_name); 262 lkdtm_kprobe = NULL; 263 lkdtm_crashpoint = NULL; 264 lkdtm_crashtype = NULL; 265 } 266 267 return ret; 268 } 269 270 #ifdef CONFIG_KPROBES 271 /* Global crash counter and spinlock. */ 272 static int crash_count = DEFAULT_COUNT; 273 static DEFINE_SPINLOCK(crash_count_lock); 274 275 /* Called by kprobe entry points. */ 276 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 277 { 278 unsigned long flags; 279 bool do_it = false; 280 281 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 282 return 0; 283 284 spin_lock_irqsave(&crash_count_lock, flags); 285 crash_count--; 286 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 287 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 288 289 if (crash_count == 0) { 290 do_it = true; 291 crash_count = cpoint_count; 292 } 293 spin_unlock_irqrestore(&crash_count_lock, flags); 294 295 if (do_it) 296 lkdtm_do_action(lkdtm_crashtype); 297 298 return 0; 299 } 300 301 static ssize_t lkdtm_debugfs_entry(struct file *f, 302 const char __user *user_buf, 303 size_t count, loff_t *off) 304 { 305 struct crashpoint *crashpoint = file_inode(f)->i_private; 306 const struct crashtype *crashtype = NULL; 307 char *buf; 308 int err; 309 310 if (count >= PAGE_SIZE) 311 return -EINVAL; 312 313 buf = (char *)__get_free_page(GFP_KERNEL); 314 if (!buf) 315 return -ENOMEM; 316 if (copy_from_user(buf, user_buf, count)) { 317 free_page((unsigned long) buf); 318 return -EFAULT; 319 } 320 /* NULL-terminate and remove enter */ 321 buf[count] = '\0'; 322 strim(buf); 323 324 crashtype = find_crashtype(buf); 325 free_page((unsigned long)buf); 326 327 if (!crashtype) 328 return -EINVAL; 329 330 err = lkdtm_register_cpoint(crashpoint, crashtype); 331 if (err < 0) 332 return err; 333 334 *off += count; 335 336 return count; 337 } 338 #endif 339 340 /* Generic read callback that just prints out the available crash types */ 341 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 342 size_t count, loff_t *off) 343 { 344 char *buf; 345 int i, n, out; 346 347 buf = (char *)__get_free_page(GFP_KERNEL); 348 if (buf == NULL) 349 return -ENOMEM; 350 351 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 352 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 353 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 354 crashtypes[i].name); 355 } 356 buf[n] = '\0'; 357 358 out = simple_read_from_buffer(user_buf, count, off, 359 buf, n); 360 free_page((unsigned long) buf); 361 362 return out; 363 } 364 365 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 366 { 367 return 0; 368 } 369 370 /* Special entry to just crash directly. Available without KPROBEs */ 371 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 372 size_t count, loff_t *off) 373 { 374 const struct crashtype *crashtype; 375 char *buf; 376 377 if (count >= PAGE_SIZE) 378 return -EINVAL; 379 if (count < 1) 380 return -EINVAL; 381 382 buf = (char *)__get_free_page(GFP_KERNEL); 383 if (!buf) 384 return -ENOMEM; 385 if (copy_from_user(buf, user_buf, count)) { 386 free_page((unsigned long) buf); 387 return -EFAULT; 388 } 389 /* NULL-terminate and remove enter */ 390 buf[count] = '\0'; 391 strim(buf); 392 393 crashtype = find_crashtype(buf); 394 free_page((unsigned long) buf); 395 if (!crashtype) 396 return -EINVAL; 397 398 pr_info("Performing direct entry %s\n", crashtype->name); 399 lkdtm_do_action(crashtype); 400 *off += count; 401 402 return count; 403 } 404 405 #ifndef MODULE 406 /* 407 * To avoid needing to export parse_args(), just don't use this code 408 * when LKDTM is built as a module. 409 */ 410 struct check_cmdline_args { 411 const char *param; 412 int value; 413 }; 414 415 static int lkdtm_parse_one(char *param, char *val, 416 const char *unused, void *arg) 417 { 418 struct check_cmdline_args *args = arg; 419 420 /* short circuit if we already found a value. */ 421 if (args->value != -ESRCH) 422 return 0; 423 if (strncmp(param, args->param, strlen(args->param)) == 0) { 424 bool bool_result; 425 int ret; 426 427 ret = kstrtobool(val, &bool_result); 428 if (ret == 0) 429 args->value = bool_result; 430 } 431 return 0; 432 } 433 434 int lkdtm_check_bool_cmdline(const char *param) 435 { 436 char *command_line; 437 struct check_cmdline_args args = { 438 .param = param, 439 .value = -ESRCH, 440 }; 441 442 command_line = kstrdup(saved_command_line, GFP_KERNEL); 443 if (!command_line) 444 return -ENOMEM; 445 446 parse_args("Setting sysctl args", command_line, 447 NULL, 0, -1, -1, &args, lkdtm_parse_one); 448 449 kfree(command_line); 450 451 return args.value; 452 } 453 #endif 454 455 static struct dentry *lkdtm_debugfs_root; 456 457 static int __init lkdtm_module_init(void) 458 { 459 struct crashpoint *crashpoint = NULL; 460 const struct crashtype *crashtype = NULL; 461 int ret; 462 int i; 463 464 /* Neither or both of these need to be set */ 465 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 466 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 467 return -EINVAL; 468 } 469 470 if (cpoint_type) { 471 crashtype = find_crashtype(cpoint_type); 472 if (!crashtype) { 473 pr_err("Unknown crashtype '%s'\n", cpoint_type); 474 return -EINVAL; 475 } 476 } 477 478 if (cpoint_name) { 479 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 480 if (!strcmp(cpoint_name, crashpoints[i].name)) 481 crashpoint = &crashpoints[i]; 482 } 483 484 /* Refuse unknown crashpoints. */ 485 if (!crashpoint) { 486 pr_err("Invalid crashpoint %s\n", cpoint_name); 487 return -EINVAL; 488 } 489 } 490 491 #ifdef CONFIG_KPROBES 492 /* Set crash count. */ 493 crash_count = cpoint_count; 494 #endif 495 496 /* Common initialization. */ 497 lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)", 498 init_uts_ns.name.release, 499 init_uts_ns.name.machine); 500 501 /* Handle test-specific initialization. */ 502 lkdtm_bugs_init(&recur_count); 503 lkdtm_perms_init(); 504 lkdtm_usercopy_init(); 505 lkdtm_heap_init(); 506 507 /* Register debugfs interface */ 508 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 509 510 /* Install debugfs trigger files. */ 511 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 512 struct crashpoint *cur = &crashpoints[i]; 513 514 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 515 &cur->fops); 516 } 517 518 /* Install crashpoint if one was selected. */ 519 if (crashpoint) { 520 ret = lkdtm_register_cpoint(crashpoint, crashtype); 521 if (ret < 0) { 522 pr_info("Invalid crashpoint %s\n", crashpoint->name); 523 goto out_err; 524 } 525 pr_info("Crash point %s of type %s registered\n", 526 crashpoint->name, cpoint_type); 527 } else { 528 pr_info("No crash points registered, enable through debugfs\n"); 529 } 530 531 return 0; 532 533 out_err: 534 debugfs_remove_recursive(lkdtm_debugfs_root); 535 return ret; 536 } 537 538 static void __exit lkdtm_module_exit(void) 539 { 540 debugfs_remove_recursive(lkdtm_debugfs_root); 541 542 /* Handle test-specific clean-up. */ 543 lkdtm_heap_exit(); 544 lkdtm_usercopy_exit(); 545 546 if (lkdtm_kprobe != NULL) 547 unregister_kprobe(lkdtm_kprobe); 548 549 kfree(lkdtm_kernel_info); 550 551 pr_info("Crash point unregistered\n"); 552 } 553 554 module_init(lkdtm_module_init); 555 module_exit(lkdtm_module_exit); 556 557 MODULE_LICENSE("GPL"); 558 MODULE_DESCRIPTION("Kernel crash testing module"); 559