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