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(EXCEPTION), 108 CRASHTYPE(LOOP), 109 CRASHTYPE(EXHAUST_STACK), 110 CRASHTYPE(CORRUPT_STACK), 111 CRASHTYPE(CORRUPT_STACK_STRONG), 112 CRASHTYPE(CORRUPT_LIST_ADD), 113 CRASHTYPE(CORRUPT_LIST_DEL), 114 CRASHTYPE(CORRUPT_USER_DS), 115 CRASHTYPE(STACK_GUARD_PAGE_LEADING), 116 CRASHTYPE(STACK_GUARD_PAGE_TRAILING), 117 CRASHTYPE(UNSET_SMEP), 118 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), 119 CRASHTYPE(OVERWRITE_ALLOCATION), 120 CRASHTYPE(WRITE_AFTER_FREE), 121 CRASHTYPE(READ_AFTER_FREE), 122 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 123 CRASHTYPE(READ_BUDDY_AFTER_FREE), 124 CRASHTYPE(SLAB_FREE_DOUBLE), 125 CRASHTYPE(SLAB_FREE_CROSS), 126 CRASHTYPE(SLAB_FREE_PAGE), 127 CRASHTYPE(SOFTLOCKUP), 128 CRASHTYPE(HARDLOCKUP), 129 CRASHTYPE(SPINLOCKUP), 130 CRASHTYPE(HUNG_TASK), 131 CRASHTYPE(EXEC_DATA), 132 CRASHTYPE(EXEC_STACK), 133 CRASHTYPE(EXEC_KMALLOC), 134 CRASHTYPE(EXEC_VMALLOC), 135 CRASHTYPE(EXEC_RODATA), 136 CRASHTYPE(EXEC_USERSPACE), 137 CRASHTYPE(EXEC_NULL), 138 CRASHTYPE(ACCESS_USERSPACE), 139 CRASHTYPE(ACCESS_NULL), 140 CRASHTYPE(WRITE_RO), 141 CRASHTYPE(WRITE_RO_AFTER_INIT), 142 CRASHTYPE(WRITE_KERN), 143 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 144 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 145 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 146 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 147 CRASHTYPE(REFCOUNT_DEC_ZERO), 148 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 149 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 150 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 151 CRASHTYPE(REFCOUNT_INC_ZERO), 152 CRASHTYPE(REFCOUNT_ADD_ZERO), 153 CRASHTYPE(REFCOUNT_INC_SATURATED), 154 CRASHTYPE(REFCOUNT_DEC_SATURATED), 155 CRASHTYPE(REFCOUNT_ADD_SATURATED), 156 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 157 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 158 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 159 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 160 CRASHTYPE(REFCOUNT_TIMING), 161 CRASHTYPE(ATOMIC_TIMING), 162 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 163 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 164 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 165 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 166 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 167 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 168 CRASHTYPE(USERCOPY_STACK_BEYOND), 169 CRASHTYPE(USERCOPY_KERNEL), 170 CRASHTYPE(USERCOPY_KERNEL_DS), 171 CRASHTYPE(STACKLEAK_ERASING), 172 }; 173 174 175 /* Global kprobe entry and crashtype. */ 176 static struct kprobe *lkdtm_kprobe; 177 static struct crashpoint *lkdtm_crashpoint; 178 static const struct crashtype *lkdtm_crashtype; 179 180 /* Module parameters */ 181 static int recur_count = -1; 182 module_param(recur_count, int, 0644); 183 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 184 185 static char* cpoint_name; 186 module_param(cpoint_name, charp, 0444); 187 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 188 189 static char* cpoint_type; 190 module_param(cpoint_type, charp, 0444); 191 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 192 "hitting the crash point"); 193 194 static int cpoint_count = DEFAULT_COUNT; 195 module_param(cpoint_count, int, 0644); 196 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 197 "crash point is to be hit to trigger action"); 198 199 200 /* Return the crashtype number or NULL if the name is invalid */ 201 static const struct crashtype *find_crashtype(const char *name) 202 { 203 int i; 204 205 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 206 if (!strcmp(name, crashtypes[i].name)) 207 return &crashtypes[i]; 208 } 209 210 return NULL; 211 } 212 213 /* 214 * This is forced noinline just so it distinctly shows up in the stackdump 215 * which makes validation of expected lkdtm crashes easier. 216 */ 217 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 218 { 219 if (WARN_ON(!crashtype || !crashtype->func)) 220 return; 221 crashtype->func(); 222 } 223 224 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 225 const struct crashtype *crashtype) 226 { 227 int ret; 228 229 /* If this doesn't have a symbol, just call immediately. */ 230 if (!crashpoint->kprobe.symbol_name) { 231 lkdtm_do_action(crashtype); 232 return 0; 233 } 234 235 if (lkdtm_kprobe != NULL) 236 unregister_kprobe(lkdtm_kprobe); 237 238 lkdtm_crashpoint = crashpoint; 239 lkdtm_crashtype = crashtype; 240 lkdtm_kprobe = &crashpoint->kprobe; 241 ret = register_kprobe(lkdtm_kprobe); 242 if (ret < 0) { 243 pr_info("Couldn't register kprobe %s\n", 244 crashpoint->kprobe.symbol_name); 245 lkdtm_kprobe = NULL; 246 lkdtm_crashpoint = NULL; 247 lkdtm_crashtype = NULL; 248 } 249 250 return ret; 251 } 252 253 #ifdef CONFIG_KPROBES 254 /* Global crash counter and spinlock. */ 255 static int crash_count = DEFAULT_COUNT; 256 static DEFINE_SPINLOCK(crash_count_lock); 257 258 /* Called by kprobe entry points. */ 259 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 260 { 261 unsigned long flags; 262 bool do_it = false; 263 264 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 265 return 0; 266 267 spin_lock_irqsave(&crash_count_lock, flags); 268 crash_count--; 269 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 270 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 271 272 if (crash_count == 0) { 273 do_it = true; 274 crash_count = cpoint_count; 275 } 276 spin_unlock_irqrestore(&crash_count_lock, flags); 277 278 if (do_it) 279 lkdtm_do_action(lkdtm_crashtype); 280 281 return 0; 282 } 283 284 static ssize_t lkdtm_debugfs_entry(struct file *f, 285 const char __user *user_buf, 286 size_t count, loff_t *off) 287 { 288 struct crashpoint *crashpoint = file_inode(f)->i_private; 289 const struct crashtype *crashtype = NULL; 290 char *buf; 291 int err; 292 293 if (count >= PAGE_SIZE) 294 return -EINVAL; 295 296 buf = (char *)__get_free_page(GFP_KERNEL); 297 if (!buf) 298 return -ENOMEM; 299 if (copy_from_user(buf, user_buf, count)) { 300 free_page((unsigned long) buf); 301 return -EFAULT; 302 } 303 /* NULL-terminate and remove enter */ 304 buf[count] = '\0'; 305 strim(buf); 306 307 crashtype = find_crashtype(buf); 308 free_page((unsigned long)buf); 309 310 if (!crashtype) 311 return -EINVAL; 312 313 err = lkdtm_register_cpoint(crashpoint, crashtype); 314 if (err < 0) 315 return err; 316 317 *off += count; 318 319 return count; 320 } 321 #endif 322 323 /* Generic read callback that just prints out the available crash types */ 324 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 325 size_t count, loff_t *off) 326 { 327 char *buf; 328 int i, n, out; 329 330 buf = (char *)__get_free_page(GFP_KERNEL); 331 if (buf == NULL) 332 return -ENOMEM; 333 334 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 335 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 336 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 337 crashtypes[i].name); 338 } 339 buf[n] = '\0'; 340 341 out = simple_read_from_buffer(user_buf, count, off, 342 buf, n); 343 free_page((unsigned long) buf); 344 345 return out; 346 } 347 348 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 349 { 350 return 0; 351 } 352 353 /* Special entry to just crash directly. Available without KPROBEs */ 354 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 355 size_t count, loff_t *off) 356 { 357 const struct crashtype *crashtype; 358 char *buf; 359 360 if (count >= PAGE_SIZE) 361 return -EINVAL; 362 if (count < 1) 363 return -EINVAL; 364 365 buf = (char *)__get_free_page(GFP_KERNEL); 366 if (!buf) 367 return -ENOMEM; 368 if (copy_from_user(buf, user_buf, count)) { 369 free_page((unsigned long) buf); 370 return -EFAULT; 371 } 372 /* NULL-terminate and remove enter */ 373 buf[count] = '\0'; 374 strim(buf); 375 376 crashtype = find_crashtype(buf); 377 free_page((unsigned long) buf); 378 if (!crashtype) 379 return -EINVAL; 380 381 pr_info("Performing direct entry %s\n", crashtype->name); 382 lkdtm_do_action(crashtype); 383 *off += count; 384 385 return count; 386 } 387 388 static struct dentry *lkdtm_debugfs_root; 389 390 static int __init lkdtm_module_init(void) 391 { 392 struct crashpoint *crashpoint = NULL; 393 const struct crashtype *crashtype = NULL; 394 int ret; 395 int i; 396 397 /* Neither or both of these need to be set */ 398 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 399 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 400 return -EINVAL; 401 } 402 403 if (cpoint_type) { 404 crashtype = find_crashtype(cpoint_type); 405 if (!crashtype) { 406 pr_err("Unknown crashtype '%s'\n", cpoint_type); 407 return -EINVAL; 408 } 409 } 410 411 if (cpoint_name) { 412 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 413 if (!strcmp(cpoint_name, crashpoints[i].name)) 414 crashpoint = &crashpoints[i]; 415 } 416 417 /* Refuse unknown crashpoints. */ 418 if (!crashpoint) { 419 pr_err("Invalid crashpoint %s\n", cpoint_name); 420 return -EINVAL; 421 } 422 } 423 424 #ifdef CONFIG_KPROBES 425 /* Set crash count. */ 426 crash_count = cpoint_count; 427 #endif 428 429 /* Handle test-specific initialization. */ 430 lkdtm_bugs_init(&recur_count); 431 lkdtm_perms_init(); 432 lkdtm_usercopy_init(); 433 lkdtm_heap_init(); 434 435 /* Register debugfs interface */ 436 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 437 438 /* Install debugfs trigger files. */ 439 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 440 struct crashpoint *cur = &crashpoints[i]; 441 442 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 443 &cur->fops); 444 } 445 446 /* Install crashpoint if one was selected. */ 447 if (crashpoint) { 448 ret = lkdtm_register_cpoint(crashpoint, crashtype); 449 if (ret < 0) { 450 pr_info("Invalid crashpoint %s\n", crashpoint->name); 451 goto out_err; 452 } 453 pr_info("Crash point %s of type %s registered\n", 454 crashpoint->name, cpoint_type); 455 } else { 456 pr_info("No crash points registered, enable through debugfs\n"); 457 } 458 459 return 0; 460 461 out_err: 462 debugfs_remove_recursive(lkdtm_debugfs_root); 463 return ret; 464 } 465 466 static void __exit lkdtm_module_exit(void) 467 { 468 debugfs_remove_recursive(lkdtm_debugfs_root); 469 470 /* Handle test-specific clean-up. */ 471 lkdtm_heap_exit(); 472 lkdtm_usercopy_exit(); 473 474 if (lkdtm_kprobe != NULL) 475 unregister_kprobe(lkdtm_kprobe); 476 477 pr_info("Crash point unregistered\n"); 478 } 479 480 module_init(lkdtm_module_init); 481 module_exit(lkdtm_module_exit); 482 483 MODULE_LICENSE("GPL"); 484 MODULE_DESCRIPTION("Kernel crash testing module"); 485