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(CORRUPT_PAC), 120 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE), 121 CRASHTYPE(OVERWRITE_ALLOCATION), 122 CRASHTYPE(WRITE_AFTER_FREE), 123 CRASHTYPE(READ_AFTER_FREE), 124 CRASHTYPE(WRITE_BUDDY_AFTER_FREE), 125 CRASHTYPE(READ_BUDDY_AFTER_FREE), 126 CRASHTYPE(SLAB_FREE_DOUBLE), 127 CRASHTYPE(SLAB_FREE_CROSS), 128 CRASHTYPE(SLAB_FREE_PAGE), 129 CRASHTYPE(SOFTLOCKUP), 130 CRASHTYPE(HARDLOCKUP), 131 CRASHTYPE(SPINLOCKUP), 132 CRASHTYPE(HUNG_TASK), 133 CRASHTYPE(EXEC_DATA), 134 CRASHTYPE(EXEC_STACK), 135 CRASHTYPE(EXEC_KMALLOC), 136 CRASHTYPE(EXEC_VMALLOC), 137 CRASHTYPE(EXEC_RODATA), 138 CRASHTYPE(EXEC_USERSPACE), 139 CRASHTYPE(EXEC_NULL), 140 CRASHTYPE(ACCESS_USERSPACE), 141 CRASHTYPE(ACCESS_NULL), 142 CRASHTYPE(WRITE_RO), 143 CRASHTYPE(WRITE_RO_AFTER_INIT), 144 CRASHTYPE(WRITE_KERN), 145 CRASHTYPE(REFCOUNT_INC_OVERFLOW), 146 CRASHTYPE(REFCOUNT_ADD_OVERFLOW), 147 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW), 148 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW), 149 CRASHTYPE(REFCOUNT_DEC_ZERO), 150 CRASHTYPE(REFCOUNT_DEC_NEGATIVE), 151 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE), 152 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE), 153 CRASHTYPE(REFCOUNT_INC_ZERO), 154 CRASHTYPE(REFCOUNT_ADD_ZERO), 155 CRASHTYPE(REFCOUNT_INC_SATURATED), 156 CRASHTYPE(REFCOUNT_DEC_SATURATED), 157 CRASHTYPE(REFCOUNT_ADD_SATURATED), 158 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED), 159 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED), 160 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED), 161 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED), 162 CRASHTYPE(REFCOUNT_TIMING), 163 CRASHTYPE(ATOMIC_TIMING), 164 CRASHTYPE(USERCOPY_HEAP_SIZE_TO), 165 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM), 166 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO), 167 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM), 168 CRASHTYPE(USERCOPY_STACK_FRAME_TO), 169 CRASHTYPE(USERCOPY_STACK_FRAME_FROM), 170 CRASHTYPE(USERCOPY_STACK_BEYOND), 171 CRASHTYPE(USERCOPY_KERNEL), 172 CRASHTYPE(USERCOPY_KERNEL_DS), 173 CRASHTYPE(STACKLEAK_ERASING), 174 CRASHTYPE(CFI_FORWARD_PROTO), 175 #ifdef CONFIG_X86_32 176 CRASHTYPE(DOUBLE_FAULT), 177 #endif 178 }; 179 180 181 /* Global kprobe entry and crashtype. */ 182 static struct kprobe *lkdtm_kprobe; 183 static struct crashpoint *lkdtm_crashpoint; 184 static const struct crashtype *lkdtm_crashtype; 185 186 /* Module parameters */ 187 static int recur_count = -1; 188 module_param(recur_count, int, 0644); 189 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); 190 191 static char* cpoint_name; 192 module_param(cpoint_name, charp, 0444); 193 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); 194 195 static char* cpoint_type; 196 module_param(cpoint_type, charp, 0444); 197 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 198 "hitting the crash point"); 199 200 static int cpoint_count = DEFAULT_COUNT; 201 module_param(cpoint_count, int, 0644); 202 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\ 203 "crash point is to be hit to trigger action"); 204 205 206 /* Return the crashtype number or NULL if the name is invalid */ 207 static const struct crashtype *find_crashtype(const char *name) 208 { 209 int i; 210 211 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 212 if (!strcmp(name, crashtypes[i].name)) 213 return &crashtypes[i]; 214 } 215 216 return NULL; 217 } 218 219 /* 220 * This is forced noinline just so it distinctly shows up in the stackdump 221 * which makes validation of expected lkdtm crashes easier. 222 */ 223 static noinline void lkdtm_do_action(const struct crashtype *crashtype) 224 { 225 if (WARN_ON(!crashtype || !crashtype->func)) 226 return; 227 crashtype->func(); 228 } 229 230 static int lkdtm_register_cpoint(struct crashpoint *crashpoint, 231 const struct crashtype *crashtype) 232 { 233 int ret; 234 235 /* If this doesn't have a symbol, just call immediately. */ 236 if (!crashpoint->kprobe.symbol_name) { 237 lkdtm_do_action(crashtype); 238 return 0; 239 } 240 241 if (lkdtm_kprobe != NULL) 242 unregister_kprobe(lkdtm_kprobe); 243 244 lkdtm_crashpoint = crashpoint; 245 lkdtm_crashtype = crashtype; 246 lkdtm_kprobe = &crashpoint->kprobe; 247 ret = register_kprobe(lkdtm_kprobe); 248 if (ret < 0) { 249 pr_info("Couldn't register kprobe %s\n", 250 crashpoint->kprobe.symbol_name); 251 lkdtm_kprobe = NULL; 252 lkdtm_crashpoint = NULL; 253 lkdtm_crashtype = NULL; 254 } 255 256 return ret; 257 } 258 259 #ifdef CONFIG_KPROBES 260 /* Global crash counter and spinlock. */ 261 static int crash_count = DEFAULT_COUNT; 262 static DEFINE_SPINLOCK(crash_count_lock); 263 264 /* Called by kprobe entry points. */ 265 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) 266 { 267 unsigned long flags; 268 bool do_it = false; 269 270 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) 271 return 0; 272 273 spin_lock_irqsave(&crash_count_lock, flags); 274 crash_count--; 275 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", 276 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count); 277 278 if (crash_count == 0) { 279 do_it = true; 280 crash_count = cpoint_count; 281 } 282 spin_unlock_irqrestore(&crash_count_lock, flags); 283 284 if (do_it) 285 lkdtm_do_action(lkdtm_crashtype); 286 287 return 0; 288 } 289 290 static ssize_t lkdtm_debugfs_entry(struct file *f, 291 const char __user *user_buf, 292 size_t count, loff_t *off) 293 { 294 struct crashpoint *crashpoint = file_inode(f)->i_private; 295 const struct crashtype *crashtype = NULL; 296 char *buf; 297 int err; 298 299 if (count >= PAGE_SIZE) 300 return -EINVAL; 301 302 buf = (char *)__get_free_page(GFP_KERNEL); 303 if (!buf) 304 return -ENOMEM; 305 if (copy_from_user(buf, user_buf, count)) { 306 free_page((unsigned long) buf); 307 return -EFAULT; 308 } 309 /* NULL-terminate and remove enter */ 310 buf[count] = '\0'; 311 strim(buf); 312 313 crashtype = find_crashtype(buf); 314 free_page((unsigned long)buf); 315 316 if (!crashtype) 317 return -EINVAL; 318 319 err = lkdtm_register_cpoint(crashpoint, crashtype); 320 if (err < 0) 321 return err; 322 323 *off += count; 324 325 return count; 326 } 327 #endif 328 329 /* Generic read callback that just prints out the available crash types */ 330 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, 331 size_t count, loff_t *off) 332 { 333 char *buf; 334 int i, n, out; 335 336 buf = (char *)__get_free_page(GFP_KERNEL); 337 if (buf == NULL) 338 return -ENOMEM; 339 340 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); 341 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) { 342 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", 343 crashtypes[i].name); 344 } 345 buf[n] = '\0'; 346 347 out = simple_read_from_buffer(user_buf, count, off, 348 buf, n); 349 free_page((unsigned long) buf); 350 351 return out; 352 } 353 354 static int lkdtm_debugfs_open(struct inode *inode, struct file *file) 355 { 356 return 0; 357 } 358 359 /* Special entry to just crash directly. Available without KPROBEs */ 360 static ssize_t direct_entry(struct file *f, const char __user *user_buf, 361 size_t count, loff_t *off) 362 { 363 const struct crashtype *crashtype; 364 char *buf; 365 366 if (count >= PAGE_SIZE) 367 return -EINVAL; 368 if (count < 1) 369 return -EINVAL; 370 371 buf = (char *)__get_free_page(GFP_KERNEL); 372 if (!buf) 373 return -ENOMEM; 374 if (copy_from_user(buf, user_buf, count)) { 375 free_page((unsigned long) buf); 376 return -EFAULT; 377 } 378 /* NULL-terminate and remove enter */ 379 buf[count] = '\0'; 380 strim(buf); 381 382 crashtype = find_crashtype(buf); 383 free_page((unsigned long) buf); 384 if (!crashtype) 385 return -EINVAL; 386 387 pr_info("Performing direct entry %s\n", crashtype->name); 388 lkdtm_do_action(crashtype); 389 *off += count; 390 391 return count; 392 } 393 394 static struct dentry *lkdtm_debugfs_root; 395 396 static int __init lkdtm_module_init(void) 397 { 398 struct crashpoint *crashpoint = NULL; 399 const struct crashtype *crashtype = NULL; 400 int ret; 401 int i; 402 403 /* Neither or both of these need to be set */ 404 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) { 405 pr_err("Need both cpoint_type and cpoint_name or neither\n"); 406 return -EINVAL; 407 } 408 409 if (cpoint_type) { 410 crashtype = find_crashtype(cpoint_type); 411 if (!crashtype) { 412 pr_err("Unknown crashtype '%s'\n", cpoint_type); 413 return -EINVAL; 414 } 415 } 416 417 if (cpoint_name) { 418 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 419 if (!strcmp(cpoint_name, crashpoints[i].name)) 420 crashpoint = &crashpoints[i]; 421 } 422 423 /* Refuse unknown crashpoints. */ 424 if (!crashpoint) { 425 pr_err("Invalid crashpoint %s\n", cpoint_name); 426 return -EINVAL; 427 } 428 } 429 430 #ifdef CONFIG_KPROBES 431 /* Set crash count. */ 432 crash_count = cpoint_count; 433 #endif 434 435 /* Handle test-specific initialization. */ 436 lkdtm_bugs_init(&recur_count); 437 lkdtm_perms_init(); 438 lkdtm_usercopy_init(); 439 lkdtm_heap_init(); 440 441 /* Register debugfs interface */ 442 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); 443 444 /* Install debugfs trigger files. */ 445 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { 446 struct crashpoint *cur = &crashpoints[i]; 447 448 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, 449 &cur->fops); 450 } 451 452 /* Install crashpoint if one was selected. */ 453 if (crashpoint) { 454 ret = lkdtm_register_cpoint(crashpoint, crashtype); 455 if (ret < 0) { 456 pr_info("Invalid crashpoint %s\n", crashpoint->name); 457 goto out_err; 458 } 459 pr_info("Crash point %s of type %s registered\n", 460 crashpoint->name, cpoint_type); 461 } else { 462 pr_info("No crash points registered, enable through debugfs\n"); 463 } 464 465 return 0; 466 467 out_err: 468 debugfs_remove_recursive(lkdtm_debugfs_root); 469 return ret; 470 } 471 472 static void __exit lkdtm_module_exit(void) 473 { 474 debugfs_remove_recursive(lkdtm_debugfs_root); 475 476 /* Handle test-specific clean-up. */ 477 lkdtm_heap_exit(); 478 lkdtm_usercopy_exit(); 479 480 if (lkdtm_kprobe != NULL) 481 unregister_kprobe(lkdtm_kprobe); 482 483 pr_info("Crash point unregistered\n"); 484 } 485 486 module_init(lkdtm_module_init); 487 module_exit(lkdtm_module_exit); 488 489 MODULE_LICENSE("GPL"); 490 MODULE_DESCRIPTION("Kernel crash testing module"); 491