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(OVERWRITE_ALLOCATION), 121 CRASHTYPE(WRITE_AFTER_FREE), 122 CRASHTYPE(READ_AFTER_FREE), 123 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 124 CRASHTYPE(READ_BUDDY_AFTER_FREE), 125 CRASHTYPE(SLAB_FREE_DOUBLE), 126 CRASHTYPE(SLAB_FREE_CROSS), 127 CRASHTYPE(SLAB_FREE_PAGE), 128 CRASHTYPE(SOFTLOCKUP), 129 CRASHTYPE(HARDLOCKUP), 130 CRASHTYPE(SPINLOCKUP), 131 CRASHTYPE(HUNG_TASK), 132 CRASHTYPE(OVERFLOW_SIGNED), 133 CRASHTYPE(OVERFLOW_UNSIGNED), 134 CRASHTYPE(ARRAY_BOUNDS), 135 CRASHTYPE(EXEC_DATA), 136 CRASHTYPE(EXEC_STACK), 137 CRASHTYPE(EXEC_KMALLOC), 138 CRASHTYPE(EXEC_VMALLOC), 139 CRASHTYPE(EXEC_RODATA), 140 CRASHTYPE(EXEC_USERSPACE), 141 CRASHTYPE(EXEC_NULL), 142 CRASHTYPE(ACCESS_USERSPACE), 143 CRASHTYPE(ACCESS_NULL), 144 CRASHTYPE(WRITE_RO), 145 CRASHTYPE(WRITE_RO_AFTER_INIT), 146 CRASHTYPE(WRITE_KERN), 147 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 148 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 149 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 150 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 151 CRASHTYPE(REFCOUNT_DEC_ZERO), 152 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 153 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 154 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 155 CRASHTYPE(REFCOUNT_INC_ZERO), 156 CRASHTYPE(REFCOUNT_ADD_ZERO), 157 CRASHTYPE(REFCOUNT_INC_SATURATED), 158 CRASHTYPE(REFCOUNT_DEC_SATURATED), 159 CRASHTYPE(REFCOUNT_ADD_SATURATED), 160 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 161 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 162 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 163 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 164 CRASHTYPE(REFCOUNT_TIMING), 165 CRASHTYPE(ATOMIC_TIMING), 166 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 167 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 168 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 169 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 170 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 171 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 172 CRASHTYPE(USERCOPY_STACK_BEYOND), 173 CRASHTYPE(USERCOPY_KERNEL), 174 CRASHTYPE(STACKLEAK_ERASING), 175 CRASHTYPE(CFI_FORWARD_PROTO), 176 #ifdef CONFIG_X86_32 177 CRASHTYPE(DOUBLE_FAULT), 178 #endif 179 }; 180 181 182 /* Global kprobe entry and crashtype. */ 183 static struct kprobe *lkdtm_kprobe; 184 static struct crashpoint *lkdtm_crashpoint; 185 static const struct crashtype *lkdtm_crashtype; 186 187 /* Module parameters */ 188 static int recur_count = -1; 189 module_param(recur_count, int, 0644); 190 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 191 192 static char* cpoint_name; 193 module_param(cpoint_name, charp, 0444); 194 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 195 196 static char* cpoint_type; 197 module_param(cpoint_type, charp, 0444); 198 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 199 "hitting the crash point"); 200 201 static int cpoint_count = DEFAULT_COUNT; 202 module_param(cpoint_count, int, 0644); 203 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 204 "crash point is to be hit to trigger action"); 205 206 207 /* Return the crashtype number or NULL if the name is invalid */ 208 static const struct crashtype *find_crashtype(const char *name) 209 { 210 int i; 211 212 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 213 if (!strcmp(name, crashtypes[i].name)) 214 return &crashtypes[i]; 215 } 216 217 return NULL; 218 } 219 220 /* 221 * This is forced noinline just so it distinctly shows up in the stackdump 222 * which makes validation of expected lkdtm crashes easier. 223 */ 224 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 225 { 226 if (WARN_ON(!crashtype || !crashtype->func)) 227 return; 228 crashtype->func(); 229 } 230 231 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 232 const struct crashtype *crashtype) 233 { 234 int ret; 235 236 /* If this doesn't have a symbol, just call immediately. */ 237 if (!crashpoint->kprobe.symbol_name) { 238 lkdtm_do_action(crashtype); 239 return 0; 240 } 241 242 if (lkdtm_kprobe != NULL) 243 unregister_kprobe(lkdtm_kprobe); 244 245 lkdtm_crashpoint = crashpoint; 246 lkdtm_crashtype = crashtype; 247 lkdtm_kprobe = &crashpoint->kprobe; 248 ret = register_kprobe(lkdtm_kprobe); 249 if (ret < 0) { 250 pr_info("Couldn't register kprobe %s\n", 251 crashpoint->kprobe.symbol_name); 252 lkdtm_kprobe = NULL; 253 lkdtm_crashpoint = NULL; 254 lkdtm_crashtype = NULL; 255 } 256 257 return ret; 258 } 259 260 #ifdef CONFIG_KPROBES 261 /* Global crash counter and spinlock. */ 262 static int crash_count = DEFAULT_COUNT; 263 static DEFINE_SPINLOCK(crash_count_lock); 264 265 /* Called by kprobe entry points. */ 266 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 267 { 268 unsigned long flags; 269 bool do_it = false; 270 271 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 272 return 0; 273 274 spin_lock_irqsave(&crash_count_lock, flags); 275 crash_count--; 276 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 277 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 278 279 if (crash_count == 0) { 280 do_it = true; 281 crash_count = cpoint_count; 282 } 283 spin_unlock_irqrestore(&crash_count_lock, flags); 284 285 if (do_it) 286 lkdtm_do_action(lkdtm_crashtype); 287 288 return 0; 289 } 290 291 static ssize_t lkdtm_debugfs_entry(struct file *f, 292 const char __user *user_buf, 293 size_t count, loff_t *off) 294 { 295 struct crashpoint *crashpoint = file_inode(f)->i_private; 296 const struct crashtype *crashtype = NULL; 297 char *buf; 298 int err; 299 300 if (count >= PAGE_SIZE) 301 return -EINVAL; 302 303 buf = (char *)__get_free_page(GFP_KERNEL); 304 if (!buf) 305 return -ENOMEM; 306 if (copy_from_user(buf, user_buf, count)) { 307 free_page((unsigned long) buf); 308 return -EFAULT; 309 } 310 /* NULL-terminate and remove enter */ 311 buf[count] = '\0'; 312 strim(buf); 313 314 crashtype = find_crashtype(buf); 315 free_page((unsigned long)buf); 316 317 if (!crashtype) 318 return -EINVAL; 319 320 err = lkdtm_register_cpoint(crashpoint, crashtype); 321 if (err < 0) 322 return err; 323 324 *off += count; 325 326 return count; 327 } 328 #endif 329 330 /* Generic read callback that just prints out the available crash types */ 331 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 332 size_t count, loff_t *off) 333 { 334 char *buf; 335 int i, n, out; 336 337 buf = (char *)__get_free_page(GFP_KERNEL); 338 if (buf == NULL) 339 return -ENOMEM; 340 341 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 342 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 343 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 344 crashtypes[i].name); 345 } 346 buf[n] = '\0'; 347 348 out = simple_read_from_buffer(user_buf, count, off, 349 buf, n); 350 free_page((unsigned long) buf); 351 352 return out; 353 } 354 355 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 356 { 357 return 0; 358 } 359 360 /* Special entry to just crash directly. Available without KPROBEs */ 361 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 362 size_t count, loff_t *off) 363 { 364 const struct crashtype *crashtype; 365 char *buf; 366 367 if (count >= PAGE_SIZE) 368 return -EINVAL; 369 if (count < 1) 370 return -EINVAL; 371 372 buf = (char *)__get_free_page(GFP_KERNEL); 373 if (!buf) 374 return -ENOMEM; 375 if (copy_from_user(buf, user_buf, count)) { 376 free_page((unsigned long) buf); 377 return -EFAULT; 378 } 379 /* NULL-terminate and remove enter */ 380 buf[count] = '\0'; 381 strim(buf); 382 383 crashtype = find_crashtype(buf); 384 free_page((unsigned long) buf); 385 if (!crashtype) 386 return -EINVAL; 387 388 pr_info("Performing direct entry %s\n", crashtype->name); 389 lkdtm_do_action(crashtype); 390 *off += count; 391 392 return count; 393 } 394 395 static struct dentry *lkdtm_debugfs_root; 396 397 static int __init lkdtm_module_init(void) 398 { 399 struct crashpoint *crashpoint = NULL; 400 const struct crashtype *crashtype = NULL; 401 int ret; 402 int i; 403 404 /* Neither or both of these need to be set */ 405 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 406 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 407 return -EINVAL; 408 } 409 410 if (cpoint_type) { 411 crashtype = find_crashtype(cpoint_type); 412 if (!crashtype) { 413 pr_err("Unknown crashtype '%s'\n", cpoint_type); 414 return -EINVAL; 415 } 416 } 417 418 if (cpoint_name) { 419 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 420 if (!strcmp(cpoint_name, crashpoints[i].name)) 421 crashpoint = &crashpoints[i]; 422 } 423 424 /* Refuse unknown crashpoints. */ 425 if (!crashpoint) { 426 pr_err("Invalid crashpoint %s\n", cpoint_name); 427 return -EINVAL; 428 } 429 } 430 431 #ifdef CONFIG_KPROBES 432 /* Set crash count. */ 433 crash_count = cpoint_count; 434 #endif 435 436 /* Handle test-specific initialization. */ 437 lkdtm_bugs_init(&recur_count); 438 lkdtm_perms_init(); 439 lkdtm_usercopy_init(); 440 lkdtm_heap_init(); 441 442 /* Register debugfs interface */ 443 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 444 445 /* Install debugfs trigger files. */ 446 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 447 struct crashpoint *cur = &crashpoints[i]; 448 449 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 450 &cur->fops); 451 } 452 453 /* Install crashpoint if one was selected. */ 454 if (crashpoint) { 455 ret = lkdtm_register_cpoint(crashpoint, crashtype); 456 if (ret < 0) { 457 pr_info("Invalid crashpoint %s\n", crashpoint->name); 458 goto out_err; 459 } 460 pr_info("Crash point %s of type %s registered\n", 461 crashpoint->name, cpoint_type); 462 } else { 463 pr_info("No crash points registered, enable through debugfs\n"); 464 } 465 466 return 0; 467 468 out_err: 469 debugfs_remove_recursive(lkdtm_debugfs_root); 470 return ret; 471 } 472 473 static void __exit lkdtm_module_exit(void) 474 { 475 debugfs_remove_recursive(lkdtm_debugfs_root); 476 477 /* Handle test-specific clean-up. */ 478 lkdtm_heap_exit(); 479 lkdtm_usercopy_exit(); 480 481 if (lkdtm_kprobe != NULL) 482 unregister_kprobe(lkdtm_kprobe); 483 484 pr_info("Crash point unregistered\n"); 485 } 486 487 module_init(lkdtm_module_init); 488 module_exit(lkdtm_module_exit); 489 490 MODULE_LICENSE("GPL"); 491 MODULE_DESCRIPTION("Kernel crash testing module"); 492