drivers/misc/lkdtm/core.c

   1 /*
   2  * Linux Kernel Dump Test Module for testing kernel crashes conditions:
   3  * induces system failures at predefined crashpoints and under predefined
   4  * operational conditions in order to evaluate the reliability of kernel
   5  * sanity checking and crash dumps obtained using different dumping
   6  * solutions.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  *
  22  * Copyright (C) IBM Corporation, 2006
  23  *
  24  * Author: Ankita Garg <ankita@in.ibm.com>
  25  *
  26  * It is adapted from the Linux Kernel Dump Test Tool by
  27  * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
  28  *
  29  * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
  30  *
  31  * See Documentation/fault-injection/provoke-crashes.txt for instructions
  32  */
  33 #include "lkdtm.h"
  34 #include <linux/fs.h>
  35 #include <linux/module.h>
  36 #include <linux/buffer_head.h>
  37 #include <linux/kprobes.h>
  38 #include <linux/list.h>
  39 #include <linux/init.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/hrtimer.h>
  42 #include <linux/slab.h>
  43 #include <scsi/scsi_cmnd.h>
  44 #include <linux/debugfs.h>
  45
  46 #ifdef CONFIG_IDE
  47 #include <linux/ide.h>
  48 #endif
  49
  50 #define DEFAULT_COUNT 10
  51
  52 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
  53 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
  54                 size_t count, loff_t *off);
  55 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
  56                             size_t count, loff_t *off);
  57
  58 #ifdef CONFIG_KPROBES
  59 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
  60 static ssize_t lkdtm_debugfs_entry(struct file *f,
  61                                    const char __user *user_buf,
  62                                    size_t count, loff_t *off);
  63 # define CRASHPOINT_KPROBE(_symbol)                             \
  64                 .kprobe = {                                     \
  65                         .symbol_name = (_symbol),               \
  66                         .pre_handler = lkdtm_kprobe_handler,    \
  67                 },
  68 # define CRASHPOINT_WRITE(_symbol)                              \
  69                 (_symbol) ? lkdtm_debugfs_entry : direct_entry
  70 #else
  71 # define CRASHPOINT_KPROBE(_symbol)
  72 # define CRASHPOINT_WRITE(_symbol)              direct_entry
  73 #endif
  74
  75 /* Crash points */
  76 struct crashpoint {
  77         const char *name;
  78         const struct file_operations fops;
  79         struct kprobe kprobe;
  80 };
  81
  82 #define CRASHPOINT(_name, _symbol)                              \
  83         {                                                       \
  84                 .name = _name,                                  \
  85                 .fops = {                                       \
  86                         .read   = lkdtm_debugfs_read,           \
  87                         .llseek = generic_file_llseek,          \
  88                         .open   = lkdtm_debugfs_open,           \
  89                         .write  = CRASHPOINT_WRITE(_symbol)     \
  90                 },                                              \
  91                 CRASHPOINT_KPROBE(_symbol)                      \
  92         }
  93
  94 /* Define the possible places where we can trigger a crash point. */
  95 static struct crashpoint crashpoints[] = {
  96         CRASHPOINT("DIRECT",             NULL),
  97 #ifdef CONFIG_KPROBES
  98         CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
  99         CRASHPOINT("INT_HW_IRQ_EN",      "handle_irq_event"),
 100         CRASHPOINT("INT_TASKLET_ENTRY",  "tasklet_action"),
 101         CRASHPOINT("FS_DEVRW",           "ll_rw_block"),
 102         CRASHPOINT("MEM_SWAPOUT",        "shrink_inactive_list"),
 103         CRASHPOINT("TIMERADD",           "hrtimer_start"),
 104         CRASHPOINT("SCSI_DISPATCH_CMD",  "scsi_dispatch_cmd"),
 105 # ifdef CONFIG_IDE
 106         CRASHPOINT("IDE_CORE_CP",        "generic_ide_ioctl"),
 107 # endif
 108 #endif
 109 };
 110
 111
 112 /* Crash types. */
 113 struct crashtype {
 114         const char *name;
 115         void (*func)(void);
 116 };
 117
 118 #define CRASHTYPE(_name)                        \
 119         {                                       \
 120                 .name = __stringify(_name),     \
 121                 .func = lkdtm_ ## _name,        \
 122         }
 123
 124 /* Define the possible types of crashes that can be triggered. */
 125 static const struct crashtype crashtypes[] = {
 126         CRASHTYPE(PANIC),
 127         CRASHTYPE(BUG),
 128         CRASHTYPE(WARNING),
 129         CRASHTYPE(EXCEPTION),
 130         CRASHTYPE(LOOP),
 131         CRASHTYPE(OVERFLOW),
 132         CRASHTYPE(CORRUPT_LIST_ADD),
 133         CRASHTYPE(CORRUPT_LIST_DEL),
 134         CRASHTYPE(CORRUPT_USER_DS),
 135         CRASHTYPE(CORRUPT_STACK),
 136         CRASHTYPE(CORRUPT_STACK_STRONG),
 137         CRASHTYPE(STACK_GUARD_PAGE_LEADING),
 138         CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
 139         CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
 140         CRASHTYPE(OVERWRITE_ALLOCATION),
 141         CRASHTYPE(WRITE_AFTER_FREE),
 142         CRASHTYPE(READ_AFTER_FREE),
 143         CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
 144         CRASHTYPE(READ_BUDDY_AFTER_FREE),
 145         CRASHTYPE(SOFTLOCKUP),
 146         CRASHTYPE(HARDLOCKUP),
 147         CRASHTYPE(SPINLOCKUP),
 148         CRASHTYPE(HUNG_TASK),
 149         CRASHTYPE(EXEC_DATA),
 150         CRASHTYPE(EXEC_STACK),
 151         CRASHTYPE(EXEC_KMALLOC),
 152         CRASHTYPE(EXEC_VMALLOC),
 153         CRASHTYPE(EXEC_RODATA),
 154         CRASHTYPE(EXEC_USERSPACE),
 155         CRASHTYPE(ACCESS_USERSPACE),
 156         CRASHTYPE(WRITE_RO),
 157         CRASHTYPE(WRITE_RO_AFTER_INIT),
 158         CRASHTYPE(WRITE_KERN),
 159         CRASHTYPE(REFCOUNT_INC_OVERFLOW),
 160         CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
 161         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
 162         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
 163         CRASHTYPE(REFCOUNT_DEC_ZERO),
 164         CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
 165         CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
 166         CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
 167         CRASHTYPE(REFCOUNT_INC_ZERO),
 168         CRASHTYPE(REFCOUNT_ADD_ZERO),
 169         CRASHTYPE(REFCOUNT_INC_SATURATED),
 170         CRASHTYPE(REFCOUNT_DEC_SATURATED),
 171         CRASHTYPE(REFCOUNT_ADD_SATURATED),
 172         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
 173         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
 174         CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
 175         CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
 176         CRASHTYPE(REFCOUNT_TIMING),
 177         CRASHTYPE(ATOMIC_TIMING),
 178         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
 179         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
 180         CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
 181         CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
 182         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 183         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 184         CRASHTYPE(USERCOPY_STACK_BEYOND),
 185         CRASHTYPE(USERCOPY_KERNEL),
 186         CRASHTYPE(USERCOPY_KERNEL_DS),
 187 };
 188
 189
 190 /* Global kprobe entry and crashtype. */
 191 static struct kprobe *lkdtm_kprobe;
 192 static struct crashpoint *lkdtm_crashpoint;
 193 static const struct crashtype *lkdtm_crashtype;
 194
 195 /* Module parameters */
 196 static int recur_count = -1;
 197 module_param(recur_count, int, 0644);
 198 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 199
 200 static char* cpoint_name;
 201 module_param(cpoint_name, charp, 0444);
 202 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 203
 204 static char* cpoint_type;
 205 module_param(cpoint_type, charp, 0444);
 206 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 207                                 "hitting the crash point");
 208
 209 static int cpoint_count = DEFAULT_COUNT;
 210 module_param(cpoint_count, int, 0644);
 211 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 212                                 "crash point is to be hit to trigger action");
 213
 214
 215 /* Return the crashtype number or NULL if the name is invalid */
 216 static const struct crashtype *find_crashtype(const char *name)
 217 {
 218         int i;
 219
 220         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 221                 if (!strcmp(name, crashtypes[i].name))
 222                         return &crashtypes[i];
 223         }
 224
 225         return NULL;
 226 }
 227
 228 /*
 229  * This is forced noinline just so it distinctly shows up in the stackdump
 230  * which makes validation of expected lkdtm crashes easier.
 231  */
 232 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
 233 {
 234         if (WARN_ON(!crashtype || !crashtype->func))
 235                 return;
 236         crashtype->func();
 237 }
 238
 239 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 240                                  const struct crashtype *crashtype)
 241 {
 242         int ret;
 243
 244         /* If this doesn't have a symbol, just call immediately. */
 245         if (!crashpoint->kprobe.symbol_name) {
 246                 lkdtm_do_action(crashtype);
 247                 return 0;
 248         }
 249
 250         if (lkdtm_kprobe != NULL)
 251                 unregister_kprobe(lkdtm_kprobe);
 252
 253         lkdtm_crashpoint = crashpoint;
 254         lkdtm_crashtype = crashtype;
 255         lkdtm_kprobe = &crashpoint->kprobe;
 256         ret = register_kprobe(lkdtm_kprobe);
 257         if (ret < 0) {
 258                 pr_info("Couldn't register kprobe %s\n",
 259                         crashpoint->kprobe.symbol_name);
 260                 lkdtm_kprobe = NULL;
 261                 lkdtm_crashpoint = NULL;
 262                 lkdtm_crashtype = NULL;
 263         }
 264
 265         return ret;
 266 }
 267
 268 #ifdef CONFIG_KPROBES
 269 /* Global crash counter and spinlock. */
 270 static int crash_count = DEFAULT_COUNT;
 271 static DEFINE_SPINLOCK(crash_count_lock);
 272
 273 /* Called by kprobe entry points. */
 274 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
 275 {
 276         unsigned long flags;
 277         bool do_it = false;
 278
 279         if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
 280                 return 0;
 281
 282         spin_lock_irqsave(&crash_count_lock, flags);
 283         crash_count--;
 284         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 285                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
 286
 287         if (crash_count == 0) {
 288                 do_it = true;
 289                 crash_count = cpoint_count;
 290         }
 291         spin_unlock_irqrestore(&crash_count_lock, flags);
 292
 293         if (do_it)
 294                 lkdtm_do_action(lkdtm_crashtype);
 295
 296         return 0;
 297 }
 298
 299 static ssize_t lkdtm_debugfs_entry(struct file *f,
 300                                    const char __user *user_buf,
 301                                    size_t count, loff_t *off)
 302 {
 303         struct crashpoint *crashpoint = file_inode(f)->i_private;
 304         const struct crashtype *crashtype = NULL;
 305         char *buf;
 306         int err;
 307
 308         if (count >= PAGE_SIZE)
 309                 return -EINVAL;
 310
 311         buf = (char *)__get_free_page(GFP_KERNEL);
 312         if (!buf)
 313                 return -ENOMEM;
 314         if (copy_from_user(buf, user_buf, count)) {
 315                 free_page((unsigned long) buf);
 316                 return -EFAULT;
 317         }
 318         /* NULL-terminate and remove enter */
 319         buf[count] = '\0';
 320         strim(buf);
 321
 322         crashtype = find_crashtype(buf);
 323         free_page((unsigned long)buf);
 324
 325         if (!crashtype)
 326                 return -EINVAL;
 327
 328         err = lkdtm_register_cpoint(crashpoint, crashtype);
 329         if (err < 0)
 330                 return err;
 331
 332         *off += count;
 333
 334         return count;
 335 }
 336 #endif
 337
 338 /* Generic read callback that just prints out the available crash types */
 339 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 340                 size_t count, loff_t *off)
 341 {
 342         char *buf;
 343         int i, n, out;
 344
 345         buf = (char *)__get_free_page(GFP_KERNEL);
 346         if (buf == NULL)
 347                 return -ENOMEM;
 348
 349         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 350         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 351                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
 352                               crashtypes[i].name);
 353         }
 354         buf[n] = '\0';
 355
 356         out = simple_read_from_buffer(user_buf, count, off,
 357                                       buf, n);
 358         free_page((unsigned long) buf);
 359
 360         return out;
 361 }
 362
 363 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 364 {
 365         return 0;
 366 }
 367
 368 /* Special entry to just crash directly. Available without KPROBEs */
 369 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 370                 size_t count, loff_t *off)
 371 {
 372         const struct crashtype *crashtype;
 373         char *buf;
 374
 375         if (count >= PAGE_SIZE)
 376                 return -EINVAL;
 377         if (count < 1)
 378                 return -EINVAL;
 379
 380         buf = (char *)__get_free_page(GFP_KERNEL);
 381         if (!buf)
 382                 return -ENOMEM;
 383         if (copy_from_user(buf, user_buf, count)) {
 384                 free_page((unsigned long) buf);
 385                 return -EFAULT;
 386         }
 387         /* NULL-terminate and remove enter */
 388         buf[count] = '\0';
 389         strim(buf);
 390
 391         crashtype = find_crashtype(buf);
 392         free_page((unsigned long) buf);
 393         if (!crashtype)
 394                 return -EINVAL;
 395
 396         pr_info("Performing direct entry %s\n", crashtype->name);
 397         lkdtm_do_action(crashtype);
 398         *off += count;
 399
 400         return count;
 401 }
 402
 403 static struct dentry *lkdtm_debugfs_root;
 404
 405 static int __init lkdtm_module_init(void)
 406 {
 407         struct crashpoint *crashpoint = NULL;
 408         const struct crashtype *crashtype = NULL;
 409         int ret = -EINVAL;
 410         int i;
 411
 412         /* Neither or both of these need to be set */
 413         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
 414                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
 415                 return -EINVAL;
 416         }
 417
 418         if (cpoint_type) {
 419                 crashtype = find_crashtype(cpoint_type);
 420                 if (!crashtype) {
 421                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
 422                         return -EINVAL;
 423                 }
 424         }
 425
 426         if (cpoint_name) {
 427                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 428                         if (!strcmp(cpoint_name, crashpoints[i].name))
 429                                 crashpoint = &crashpoints[i];
 430                 }
 431
 432                 /* Refuse unknown crashpoints. */
 433                 if (!crashpoint) {
 434                         pr_err("Invalid crashpoint %s\n", cpoint_name);
 435                         return -EINVAL;
 436                 }
 437         }
 438
 439 #ifdef CONFIG_KPROBES
 440         /* Set crash count. */
 441         crash_count = cpoint_count;
 442 #endif
 443
 444         /* Handle test-specific initialization. */
 445         lkdtm_bugs_init(&recur_count);
 446         lkdtm_perms_init();
 447         lkdtm_usercopy_init();
 448
 449         /* Register debugfs interface */
 450         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 451         if (!lkdtm_debugfs_root) {
 452                 pr_err("creating root dir failed\n");
 453                 return -ENODEV;
 454         }
 455
 456         /* Install debugfs trigger files. */
 457         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 458                 struct crashpoint *cur = &crashpoints[i];
 459                 struct dentry *de;
 460
 461                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 462                                          cur, &cur->fops);
 463                 if (de == NULL) {
 464                         pr_err("could not create crashpoint %s\n", cur->name);
 465                         goto out_err;
 466                 }
 467         }
 468
 469         /* Install crashpoint if one was selected. */
 470         if (crashpoint) {
 471                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
 472                 if (ret < 0) {
 473                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
 474                         goto out_err;
 475                 }
 476                 pr_info("Crash point %s of type %s registered\n",
 477                         crashpoint->name, cpoint_type);
 478         } else {
 479                 pr_info("No crash points registered, enable through debugfs\n");
 480         }
 481
 482         return 0;
 483
 484 out_err:
 485         debugfs_remove_recursive(lkdtm_debugfs_root);
 486         return ret;
 487 }
 488
 489 static void __exit lkdtm_module_exit(void)
 490 {
 491         debugfs_remove_recursive(lkdtm_debugfs_root);
 492
 493         /* Handle test-specific clean-up. */
 494         lkdtm_usercopy_exit();
 495
 496         if (lkdtm_kprobe != NULL)
 497                 unregister_kprobe(lkdtm_kprobe);
 498
 499         pr_info("Crash point unregistered\n");
 500 }
 501
 502 module_init(lkdtm_module_init);
 503 module_exit(lkdtm_module_exit);
 504
 505 MODULE_LICENSE("GPL");
 506 MODULE_DESCRIPTION("Kernel crash testing module");