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(CORRUPT_USER_DS), 116 CRASHTYPE(STACK_GUARD_PAGE_LEADING), 117 CRASHTYPE(STACK_GUARD_PAGE_TRAILING), 118 CRASHTYPE(UNSET_SMEP), 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(EXEC_DATA), 133 CRASHTYPE(EXEC_STACK), 134 CRASHTYPE(EXEC_KMALLOC), 135 CRASHTYPE(EXEC_VMALLOC), 136 CRASHTYPE(EXEC_RODATA), 137 CRASHTYPE(EXEC_USERSPACE), 138 CRASHTYPE(EXEC_NULL), 139 CRASHTYPE(ACCESS_USERSPACE), 140 CRASHTYPE(ACCESS_NULL), 141 CRASHTYPE(WRITE_RO), 142 CRASHTYPE(WRITE_RO_AFTER_INIT), 143 CRASHTYPE(WRITE_KERN), 144 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 145 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 146 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 147 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 148 CRASHTYPE(REFCOUNT_DEC_ZERO), 149 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 150 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 151 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 152 CRASHTYPE(REFCOUNT_INC_ZERO), 153 CRASHTYPE(REFCOUNT_ADD_ZERO), 154 CRASHTYPE(REFCOUNT_INC_SATURATED), 155 CRASHTYPE(REFCOUNT_DEC_SATURATED), 156 CRASHTYPE(REFCOUNT_ADD_SATURATED), 157 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 158 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 159 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 160 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 161 CRASHTYPE(REFCOUNT_TIMING), 162 CRASHTYPE(ATOMIC_TIMING), 163 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 164 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 165 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 166 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 167 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 168 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 169 CRASHTYPE(USERCOPY_STACK_BEYOND), 170 CRASHTYPE(USERCOPY_KERNEL), 171 CRASHTYPE(USERCOPY_KERNEL_DS), 172 CRASHTYPE(STACKLEAK_ERASING), 173 CRASHTYPE(CFI_FORWARD_PROTO), 174 }; 175 176 177 /* Global kprobe entry and crashtype. */ 178 static struct kprobe *lkdtm_kprobe; 179 static struct crashpoint *lkdtm_crashpoint; 180 static const struct crashtype *lkdtm_crashtype; 181 182 /* Module parameters */ 183 static int recur_count = -1; 184 module_param(recur_count, int, 0644); 185 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 186 187 static char* cpoint_name; 188 module_param(cpoint_name, charp, 0444); 189 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 190 191 static char* cpoint_type; 192 module_param(cpoint_type, charp, 0444); 193 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 194 "hitting the crash point"); 195 196 static int cpoint_count = DEFAULT_COUNT; 197 module_param(cpoint_count, int, 0644); 198 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 199 "crash point is to be hit to trigger action"); 200 201 202 /* Return the crashtype number or NULL if the name is invalid */ 203 static const struct crashtype *find_crashtype(const char *name) 204 { 205 int i; 206 207 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 208 if (!strcmp(name, crashtypes[i].name)) 209 return &crashtypes[i]; 210 } 211 212 return NULL; 213 } 214 215 /* 216 * This is forced noinline just so it distinctly shows up in the stackdump 217 * which makes validation of expected lkdtm crashes easier. 218 */ 219 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 220 { 221 if (WARN_ON(!crashtype || !crashtype->func)) 222 return; 223 crashtype->func(); 224 } 225 226 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 227 const struct crashtype *crashtype) 228 { 229 int ret; 230 231 /* If this doesn't have a symbol, just call immediately. */ 232 if (!crashpoint->kprobe.symbol_name) { 233 lkdtm_do_action(crashtype); 234 return 0; 235 } 236 237 if (lkdtm_kprobe != NULL) 238 unregister_kprobe(lkdtm_kprobe); 239 240 lkdtm_crashpoint = crashpoint; 241 lkdtm_crashtype = crashtype; 242 lkdtm_kprobe = &crashpoint->kprobe; 243 ret = register_kprobe(lkdtm_kprobe); 244 if (ret < 0) { 245 pr_info("Couldn't register kprobe %s\n", 246 crashpoint->kprobe.symbol_name); 247 lkdtm_kprobe = NULL; 248 lkdtm_crashpoint = NULL; 249 lkdtm_crashtype = NULL; 250 } 251 252 return ret; 253 } 254 255 #ifdef CONFIG_KPROBES 256 /* Global crash counter and spinlock. */ 257 static int crash_count = DEFAULT_COUNT; 258 static DEFINE_SPINLOCK(crash_count_lock); 259 260 /* Called by kprobe entry points. */ 261 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 262 { 263 unsigned long flags; 264 bool do_it = false; 265 266 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 267 return 0; 268 269 spin_lock_irqsave(&crash_count_lock, flags); 270 crash_count--; 271 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 272 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 273 274 if (crash_count == 0) { 275 do_it = true; 276 crash_count = cpoint_count; 277 } 278 spin_unlock_irqrestore(&crash_count_lock, flags); 279 280 if (do_it) 281 lkdtm_do_action(lkdtm_crashtype); 282 283 return 0; 284 } 285 286 static ssize_t lkdtm_debugfs_entry(struct file *f, 287 const char __user *user_buf, 288 size_t count, loff_t *off) 289 { 290 struct crashpoint *crashpoint = file_inode(f)->i_private; 291 const struct crashtype *crashtype = NULL; 292 char *buf; 293 int err; 294 295 if (count >= PAGE_SIZE) 296 return -EINVAL; 297 298 buf = (char *)__get_free_page(GFP_KERNEL); 299 if (!buf) 300 return -ENOMEM; 301 if (copy_from_user(buf, user_buf, count)) { 302 free_page((unsigned long) buf); 303 return -EFAULT; 304 } 305 /* NULL-terminate and remove enter */ 306 buf[count] = '\0'; 307 strim(buf); 308 309 crashtype = find_crashtype(buf); 310 free_page((unsigned long)buf); 311 312 if (!crashtype) 313 return -EINVAL; 314 315 err = lkdtm_register_cpoint(crashpoint, crashtype); 316 if (err < 0) 317 return err; 318 319 *off += count; 320 321 return count; 322 } 323 #endif 324 325 /* Generic read callback that just prints out the available crash types */ 326 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 327 size_t count, loff_t *off) 328 { 329 char *buf; 330 int i, n, out; 331 332 buf = (char *)__get_free_page(GFP_KERNEL); 333 if (buf == NULL) 334 return -ENOMEM; 335 336 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 337 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 338 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 339 crashtypes[i].name); 340 } 341 buf[n] = '\0'; 342 343 out = simple_read_from_buffer(user_buf, count, off, 344 buf, n); 345 free_page((unsigned long) buf); 346 347 return out; 348 } 349 350 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 351 { 352 return 0; 353 } 354 355 /* Special entry to just crash directly. Available without KPROBEs */ 356 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 357 size_t count, loff_t *off) 358 { 359 const struct crashtype *crashtype; 360 char *buf; 361 362 if (count >= PAGE_SIZE) 363 return -EINVAL; 364 if (count < 1) 365 return -EINVAL; 366 367 buf = (char *)__get_free_page(GFP_KERNEL); 368 if (!buf) 369 return -ENOMEM; 370 if (copy_from_user(buf, user_buf, count)) { 371 free_page((unsigned long) buf); 372 return -EFAULT; 373 } 374 /* NULL-terminate and remove enter */ 375 buf[count] = '\0'; 376 strim(buf); 377 378 crashtype = find_crashtype(buf); 379 free_page((unsigned long) buf); 380 if (!crashtype) 381 return -EINVAL; 382 383 pr_info("Performing direct entry %s\n", crashtype->name); 384 lkdtm_do_action(crashtype); 385 *off += count; 386 387 return count; 388 } 389 390 static struct dentry *lkdtm_debugfs_root; 391 392 static int __init lkdtm_module_init(void) 393 { 394 struct crashpoint *crashpoint = NULL; 395 const struct crashtype *crashtype = NULL; 396 int ret; 397 int i; 398 399 /* Neither or both of these need to be set */ 400 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 401 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 402 return -EINVAL; 403 } 404 405 if (cpoint_type) { 406 crashtype = find_crashtype(cpoint_type); 407 if (!crashtype) { 408 pr_err("Unknown crashtype '%s'\n", cpoint_type); 409 return -EINVAL; 410 } 411 } 412 413 if (cpoint_name) { 414 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 415 if (!strcmp(cpoint_name, crashpoints[i].name)) 416 crashpoint = &crashpoints[i]; 417 } 418 419 /* Refuse unknown crashpoints. */ 420 if (!crashpoint) { 421 pr_err("Invalid crashpoint %s\n", cpoint_name); 422 return -EINVAL; 423 } 424 } 425 426 #ifdef CONFIG_KPROBES 427 /* Set crash count. */ 428 crash_count = cpoint_count; 429 #endif 430 431 /* Handle test-specific initialization. */ 432 lkdtm_bugs_init(&recur_count); 433 lkdtm_perms_init(); 434 lkdtm_usercopy_init(); 435 lkdtm_heap_init(); 436 437 /* Register debugfs interface */ 438 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 439 440 /* Install debugfs trigger files. */ 441 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 442 struct crashpoint *cur = &crashpoints[i]; 443 444 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 445 &cur->fops); 446 } 447 448 /* Install crashpoint if one was selected. */ 449 if (crashpoint) { 450 ret = lkdtm_register_cpoint(crashpoint, crashtype); 451 if (ret < 0) { 452 pr_info("Invalid crashpoint %s\n", crashpoint->name); 453 goto out_err; 454 } 455 pr_info("Crash point %s of type %s registered\n", 456 crashpoint->name, cpoint_type); 457 } else { 458 pr_info("No crash points registered, enable through debugfs\n"); 459 } 460 461 return 0; 462 463 out_err: 464 debugfs_remove_recursive(lkdtm_debugfs_root); 465 return ret; 466 } 467 468 static void __exit lkdtm_module_exit(void) 469 { 470 debugfs_remove_recursive(lkdtm_debugfs_root); 471 472 /* Handle test-specific clean-up. */ 473 lkdtm_heap_exit(); 474 lkdtm_usercopy_exit(); 475 476 if (lkdtm_kprobe != NULL) 477 unregister_kprobe(lkdtm_kprobe); 478 479 pr_info("Crash point unregistered\n"); 480 } 481 482 module_init(lkdtm_module_init); 483 module_exit(lkdtm_module_exit); 484 485 MODULE_LICENSE("GPL"); 486 MODULE_DESCRIPTION("Kernel crash testing module"); 487