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