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_DISPATCH_CMD", "scsi_dispatch_cmd"), 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(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(FORTIFY_OBJECT), 121 CRASHTYPE(FORTIFY_SUBOBJECT), 122 CRASHTYPE(OVERWRITE_ALLOCATION), 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_FREE_DOUBLE), 128 CRASHTYPE(SLAB_FREE_CROSS), 129 CRASHTYPE(SLAB_FREE_PAGE), 130 CRASHTYPE(SOFTLOCKUP), 131 CRASHTYPE(HARDLOCKUP), 132 CRASHTYPE(SPINLOCKUP), 133 CRASHTYPE(HUNG_TASK), 134 CRASHTYPE(OVERFLOW_SIGNED), 135 CRASHTYPE(OVERFLOW_UNSIGNED), 136 CRASHTYPE(ARRAY_BOUNDS), 137 CRASHTYPE(EXEC_DATA), 138 CRASHTYPE(EXEC_STACK), 139 CRASHTYPE(EXEC_KMALLOC), 140 CRASHTYPE(EXEC_VMALLOC), 141 CRASHTYPE(EXEC_RODATA), 142 CRASHTYPE(EXEC_USERSPACE), 143 CRASHTYPE(EXEC_NULL), 144 CRASHTYPE(ACCESS_USERSPACE), 145 CRASHTYPE(ACCESS_NULL), 146 CRASHTYPE(WRITE_RO), 147 CRASHTYPE(WRITE_RO_AFTER_INIT), 148 CRASHTYPE(WRITE_KERN), 149 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 150 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 151 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 152 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 153 CRASHTYPE(REFCOUNT_DEC_ZERO), 154 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 155 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 156 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 157 CRASHTYPE(REFCOUNT_INC_ZERO), 158 CRASHTYPE(REFCOUNT_ADD_ZERO), 159 CRASHTYPE(REFCOUNT_INC_SATURATED), 160 CRASHTYPE(REFCOUNT_DEC_SATURATED), 161 CRASHTYPE(REFCOUNT_ADD_SATURATED), 162 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 163 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 164 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 165 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 166 CRASHTYPE(REFCOUNT_TIMING), 167 CRASHTYPE(ATOMIC_TIMING), 168 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 169 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 170 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 171 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 172 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 173 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 174 CRASHTYPE(USERCOPY_STACK_BEYOND), 175 CRASHTYPE(USERCOPY_KERNEL), 176 CRASHTYPE(STACKLEAK_ERASING), 177 CRASHTYPE(CFI_FORWARD_PROTO), 178 CRASHTYPE(FORTIFIED_STRSCPY), 179 #ifdef CONFIG_X86_32 180 CRASHTYPE(DOUBLE_FAULT), 181 #endif 182 #ifdef CONFIG_PPC_BOOK3S_64 183 CRASHTYPE(PPC_SLB_MULTIHIT), 184 #endif 185 }; 186 187 188 /* Global kprobe entry and crashtype. */ 189 static struct kprobe *lkdtm_kprobe; 190 static struct crashpoint *lkdtm_crashpoint; 191 static const struct crashtype *lkdtm_crashtype; 192 193 /* Module parameters */ 194 static int recur_count = -1; 195 module_param(recur_count, int, 0644); 196 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 197 198 static char* cpoint_name; 199 module_param(cpoint_name, charp, 0444); 200 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 201 202 static char* cpoint_type; 203 module_param(cpoint_type, charp, 0444); 204 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 205 "hitting the crash point"); 206 207 static int cpoint_count = DEFAULT_COUNT; 208 module_param(cpoint_count, int, 0644); 209 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 210 "crash point is to be hit to trigger action"); 211 212 213 /* Return the crashtype number or NULL if the name is invalid */ 214 static const struct crashtype *find_crashtype(const char *name) 215 { 216 int i; 217 218 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 219 if (!strcmp(name, crashtypes[i].name)) 220 return &crashtypes[i]; 221 } 222 223 return NULL; 224 } 225 226 /* 227 * This is forced noinline just so it distinctly shows up in the stackdump 228 * which makes validation of expected lkdtm crashes easier. 229 */ 230 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 231 { 232 if (WARN_ON(!crashtype || !crashtype->func)) 233 return; 234 crashtype->func(); 235 } 236 237 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 238 const struct crashtype *crashtype) 239 { 240 int ret; 241 242 /* If this doesn't have a symbol, just call immediately. */ 243 if (!crashpoint->kprobe.symbol_name) { 244 lkdtm_do_action(crashtype); 245 return 0; 246 } 247 248 if (lkdtm_kprobe != NULL) 249 unregister_kprobe(lkdtm_kprobe); 250 251 lkdtm_crashpoint = crashpoint; 252 lkdtm_crashtype = crashtype; 253 lkdtm_kprobe = &crashpoint->kprobe; 254 ret = register_kprobe(lkdtm_kprobe); 255 if (ret < 0) { 256 pr_info("Couldn't register kprobe %s\n", 257 crashpoint->kprobe.symbol_name); 258 lkdtm_kprobe = NULL; 259 lkdtm_crashpoint = NULL; 260 lkdtm_crashtype = NULL; 261 } 262 263 return ret; 264 } 265 266 #ifdef CONFIG_KPROBES 267 /* Global crash counter and spinlock. */ 268 static int crash_count = DEFAULT_COUNT; 269 static DEFINE_SPINLOCK(crash_count_lock); 270 271 /* Called by kprobe entry points. */ 272 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 273 { 274 unsigned long flags; 275 bool do_it = false; 276 277 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 278 return 0; 279 280 spin_lock_irqsave(&crash_count_lock, flags); 281 crash_count--; 282 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 283 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 284 285 if (crash_count == 0) { 286 do_it = true; 287 crash_count = cpoint_count; 288 } 289 spin_unlock_irqrestore(&crash_count_lock, flags); 290 291 if (do_it) 292 lkdtm_do_action(lkdtm_crashtype); 293 294 return 0; 295 } 296 297 static ssize_t lkdtm_debugfs_entry(struct file *f, 298 const char __user *user_buf, 299 size_t count, loff_t *off) 300 { 301 struct crashpoint *crashpoint = file_inode(f)->i_private; 302 const struct crashtype *crashtype = NULL; 303 char *buf; 304 int err; 305 306 if (count >= PAGE_SIZE) 307 return -EINVAL; 308 309 buf = (char *)__get_free_page(GFP_KERNEL); 310 if (!buf) 311 return -ENOMEM; 312 if (copy_from_user(buf, user_buf, count)) { 313 free_page((unsigned long) buf); 314 return -EFAULT; 315 } 316 /* NULL-terminate and remove enter */ 317 buf[count] = '\0'; 318 strim(buf); 319 320 crashtype = find_crashtype(buf); 321 free_page((unsigned long)buf); 322 323 if (!crashtype) 324 return -EINVAL; 325 326 err = lkdtm_register_cpoint(crashpoint, crashtype); 327 if (err < 0) 328 return err; 329 330 *off += count; 331 332 return count; 333 } 334 #endif 335 336 /* Generic read callback that just prints out the available crash types */ 337 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 338 size_t count, loff_t *off) 339 { 340 char *buf; 341 int i, n, out; 342 343 buf = (char *)__get_free_page(GFP_KERNEL); 344 if (buf == NULL) 345 return -ENOMEM; 346 347 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 348 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 349 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 350 crashtypes[i].name); 351 } 352 buf[n] = '\0'; 353 354 out = simple_read_from_buffer(user_buf, count, off, 355 buf, n); 356 free_page((unsigned long) buf); 357 358 return out; 359 } 360 361 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 362 { 363 return 0; 364 } 365 366 /* Special entry to just crash directly. Available without KPROBEs */ 367 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 368 size_t count, loff_t *off) 369 { 370 const struct crashtype *crashtype; 371 char *buf; 372 373 if (count >= PAGE_SIZE) 374 return -EINVAL; 375 if (count < 1) 376 return -EINVAL; 377 378 buf = (char *)__get_free_page(GFP_KERNEL); 379 if (!buf) 380 return -ENOMEM; 381 if (copy_from_user(buf, user_buf, count)) { 382 free_page((unsigned long) buf); 383 return -EFAULT; 384 } 385 /* NULL-terminate and remove enter */ 386 buf[count] = '\0'; 387 strim(buf); 388 389 crashtype = find_crashtype(buf); 390 free_page((unsigned long) buf); 391 if (!crashtype) 392 return -EINVAL; 393 394 pr_info("Performing direct entry %s\n", crashtype->name); 395 lkdtm_do_action(crashtype); 396 *off += count; 397 398 return count; 399 } 400 401 static struct dentry *lkdtm_debugfs_root; 402 403 static int __init lkdtm_module_init(void) 404 { 405 struct crashpoint *crashpoint = NULL; 406 const struct crashtype *crashtype = NULL; 407 int ret; 408 int i; 409 410 /* Neither or both of these need to be set */ 411 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 412 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 413 return -EINVAL; 414 } 415 416 if (cpoint_type) { 417 crashtype = find_crashtype(cpoint_type); 418 if (!crashtype) { 419 pr_err("Unknown crashtype '%s'\n", cpoint_type); 420 return -EINVAL; 421 } 422 } 423 424 if (cpoint_name) { 425 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 426 if (!strcmp(cpoint_name, crashpoints[i].name)) 427 crashpoint = &crashpoints[i]; 428 } 429 430 /* Refuse unknown crashpoints. */ 431 if (!crashpoint) { 432 pr_err("Invalid crashpoint %s\n", cpoint_name); 433 return -EINVAL; 434 } 435 } 436 437 #ifdef CONFIG_KPROBES 438 /* Set crash count. */ 439 crash_count = cpoint_count; 440 #endif 441 442 /* Handle test-specific initialization. */ 443 lkdtm_bugs_init(&recur_count); 444 lkdtm_perms_init(); 445 lkdtm_usercopy_init(); 446 lkdtm_heap_init(); 447 448 /* Register debugfs interface */ 449 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 450 451 /* Install debugfs trigger files. */ 452 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 453 struct crashpoint *cur = &crashpoints[i]; 454 455 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 456 &cur->fops); 457 } 458 459 /* Install crashpoint if one was selected. */ 460 if (crashpoint) { 461 ret = lkdtm_register_cpoint(crashpoint, crashtype); 462 if (ret < 0) { 463 pr_info("Invalid crashpoint %s\n", crashpoint->name); 464 goto out_err; 465 } 466 pr_info("Crash point %s of type %s registered\n", 467 crashpoint->name, cpoint_type); 468 } else { 469 pr_info("No crash points registered, enable through debugfs\n"); 470 } 471 472 return 0; 473 474 out_err: 475 debugfs_remove_recursive(lkdtm_debugfs_root); 476 return ret; 477 } 478 479 static void __exit lkdtm_module_exit(void) 480 { 481 debugfs_remove_recursive(lkdtm_debugfs_root); 482 483 /* Handle test-specific clean-up. */ 484 lkdtm_heap_exit(); 485 lkdtm_usercopy_exit(); 486 487 if (lkdtm_kprobe != NULL) 488 unregister_kprobe(lkdtm_kprobe); 489 490 pr_info("Crash point unregistered\n"); 491 } 492 493 module_init(lkdtm_module_init); 494 module_exit(lkdtm_module_exit); 495 496 MODULE_LICENSE("GPL"); 497 MODULE_DESCRIPTION("Kernel crash testing module"); 498