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_FLAG_TO),
 181         CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
 182         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 183         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 184         CRASHTYPE(USERCOPY_STACK_BEYOND),
 185         CRASHTYPE(USERCOPY_KERNEL),
 186 };
 187
 188
 189 /* Global kprobe entry and crashtype. */
 190 static struct kprobe *lkdtm_kprobe;
 191 static struct crashpoint *lkdtm_crashpoint;
 192 static const struct crashtype *lkdtm_crashtype;
 193
 194 /* Module parameters */
 195 static int recur_count = -1;
 196 module_param(recur_count, int, 0644);
 197 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 198
 199 static char* cpoint_name;
 200 module_param(cpoint_name, charp, 0444);
 201 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 202
 203 static char* cpoint_type;
 204 module_param(cpoint_type, charp, 0444);
 205 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 206                                 "hitting the crash point");
 207
 208 static int cpoint_count = DEFAULT_COUNT;
 209 module_param(cpoint_count, int, 0644);
 210 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 211                                 "crash point is to be hit to trigger action");
 212
 213
 214 /* Return the crashtype number or NULL if the name is invalid */
 215 static const struct crashtype *find_crashtype(const char *name)
 216 {
 217         int i;
 218
 219         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 220                 if (!strcmp(name, crashtypes[i].name))
 221                         return &crashtypes[i];
 222         }
 223
 224         return NULL;
 225 }
 226
 227 /*
 228  * This is forced noinline just so it distinctly shows up in the stackdump
 229  * which makes validation of expected lkdtm crashes easier.
 230  */
 231 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
 232 {
 233         if (WARN_ON(!crashtype || !crashtype->func))
 234                 return;
 235         crashtype->func();
 236 }
 237
 238 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 239                                  const struct crashtype *crashtype)
 240 {
 241         int ret;
 242
 243         /* If this doesn't have a symbol, just call immediately. */
 244         if (!crashpoint->kprobe.symbol_name) {
 245                 lkdtm_do_action(crashtype);
 246                 return 0;
 247         }
 248
 249         if (lkdtm_kprobe != NULL)
 250                 unregister_kprobe(lkdtm_kprobe);
 251
 252         lkdtm_crashpoint = crashpoint;
 253         lkdtm_crashtype = crashtype;
 254         lkdtm_kprobe = &crashpoint->kprobe;
 255         ret = register_kprobe(lkdtm_kprobe);
 256         if (ret < 0) {
 257                 pr_info("Couldn't register kprobe %s\n",
 258                         crashpoint->kprobe.symbol_name);
 259                 lkdtm_kprobe = NULL;
 260                 lkdtm_crashpoint = NULL;
 261                 lkdtm_crashtype = NULL;
 262         }
 263
 264         return ret;
 265 }
 266
 267 #ifdef CONFIG_KPROBES
 268 /* Global crash counter and spinlock. */
 269 static int crash_count = DEFAULT_COUNT;
 270 static DEFINE_SPINLOCK(crash_count_lock);
 271
 272 /* Called by kprobe entry points. */
 273 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
 274 {
 275         unsigned long flags;
 276         bool do_it = false;
 277
 278         if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
 279                 return 0;
 280
 281         spin_lock_irqsave(&crash_count_lock, flags);
 282         crash_count--;
 283         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 284                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
 285
 286         if (crash_count == 0) {
 287                 do_it = true;
 288                 crash_count = cpoint_count;
 289         }
 290         spin_unlock_irqrestore(&crash_count_lock, flags);
 291
 292         if (do_it)
 293                 lkdtm_do_action(lkdtm_crashtype);
 294
 295         return 0;
 296 }
 297
 298 static ssize_t lkdtm_debugfs_entry(struct file *f,
 299                                    const char __user *user_buf,
 300                                    size_t count, loff_t *off)
 301 {
 302         struct crashpoint *crashpoint = file_inode(f)->i_private;
 303         const struct crashtype *crashtype = NULL;
 304         char *buf;
 305         int err;
 306
 307         if (count >= PAGE_SIZE)
 308                 return -EINVAL;
 309
 310         buf = (char *)__get_free_page(GFP_KERNEL);
 311         if (!buf)
 312                 return -ENOMEM;
 313         if (copy_from_user(buf, user_buf, count)) {
 314                 free_page((unsigned long) buf);
 315                 return -EFAULT;
 316         }
 317         /* NULL-terminate and remove enter */
 318         buf[count] = '\0';
 319         strim(buf);
 320
 321         crashtype = find_crashtype(buf);
 322         free_page((unsigned long)buf);
 323
 324         if (!crashtype)
 325                 return -EINVAL;
 326
 327         err = lkdtm_register_cpoint(crashpoint, crashtype);
 328         if (err < 0)
 329                 return err;
 330
 331         *off += count;
 332
 333         return count;
 334 }
 335 #endif
 336
 337 /* Generic read callback that just prints out the available crash types */
 338 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 339                 size_t count, loff_t *off)
 340 {
 341         char *buf;
 342         int i, n, out;
 343
 344         buf = (char *)__get_free_page(GFP_KERNEL);
 345         if (buf == NULL)
 346                 return -ENOMEM;
 347
 348         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 349         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 350                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
 351                               crashtypes[i].name);
 352         }
 353         buf[n] = '\0';
 354
 355         out = simple_read_from_buffer(user_buf, count, off,
 356                                       buf, n);
 357         free_page((unsigned long) buf);
 358
 359         return out;
 360 }
 361
 362 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 363 {
 364         return 0;
 365 }
 366
 367 /* Special entry to just crash directly. Available without KPROBEs */
 368 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 369                 size_t count, loff_t *off)
 370 {
 371         const struct crashtype *crashtype;
 372         char *buf;
 373
 374         if (count >= PAGE_SIZE)
 375                 return -EINVAL;
 376         if (count < 1)
 377                 return -EINVAL;
 378
 379         buf = (char *)__get_free_page(GFP_KERNEL);
 380         if (!buf)
 381                 return -ENOMEM;
 382         if (copy_from_user(buf, user_buf, count)) {
 383                 free_page((unsigned long) buf);
 384                 return -EFAULT;
 385         }
 386         /* NULL-terminate and remove enter */
 387         buf[count] = '\0';
 388         strim(buf);
 389
 390         crashtype = find_crashtype(buf);
 391         free_page((unsigned long) buf);
 392         if (!crashtype)
 393                 return -EINVAL;
 394
 395         pr_info("Performing direct entry %s\n", crashtype->name);
 396         lkdtm_do_action(crashtype);
 397         *off += count;
 398
 399         return count;
 400 }
 401
 402 static struct dentry *lkdtm_debugfs_root;
 403
 404 static int __init lkdtm_module_init(void)
 405 {
 406         struct crashpoint *crashpoint = NULL;
 407         const struct crashtype *crashtype = NULL;
 408         int ret = -EINVAL;
 409         int i;
 410
 411         /* Neither or both of these need to be set */
 412         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
 413                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
 414                 return -EINVAL;
 415         }
 416
 417         if (cpoint_type) {
 418                 crashtype = find_crashtype(cpoint_type);
 419                 if (!crashtype) {
 420                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
 421                         return -EINVAL;
 422                 }
 423         }
 424
 425         if (cpoint_name) {
 426                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 427                         if (!strcmp(cpoint_name, crashpoints[i].name))
 428                                 crashpoint = &crashpoints[i];
 429                 }
 430
 431                 /* Refuse unknown crashpoints. */
 432                 if (!crashpoint) {
 433                         pr_err("Invalid crashpoint %s\n", cpoint_name);
 434                         return -EINVAL;
 435                 }
 436         }
 437
 438 #ifdef CONFIG_KPROBES
 439         /* Set crash count. */
 440         crash_count = cpoint_count;
 441 #endif
 442
 443         /* Handle test-specific initialization. */
 444         lkdtm_bugs_init(&recur_count);
 445         lkdtm_perms_init();
 446         lkdtm_usercopy_init();
 447
 448         /* Register debugfs interface */
 449         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 450         if (!lkdtm_debugfs_root) {
 451                 pr_err("creating root dir failed\n");
 452                 return -ENODEV;
 453         }
 454
 455         /* Install debugfs trigger files. */
 456         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 457                 struct crashpoint *cur = &crashpoints[i];
 458                 struct dentry *de;
 459
 460                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 461                                          cur, &cur->fops);
 462                 if (de == NULL) {
 463                         pr_err("could not create crashpoint %s\n", cur->name);
 464                         goto out_err;
 465                 }
 466         }
 467
 468         /* Install crashpoint if one was selected. */
 469         if (crashpoint) {
 470                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
 471                 if (ret < 0) {
 472                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
 473                         goto out_err;
 474                 }
 475                 pr_info("Crash point %s of type %s registered\n",
 476                         crashpoint->name, cpoint_type);
 477         } else {
 478                 pr_info("No crash points registered, enable through debugfs\n");
 479         }
 480
 481         return 0;
 482
 483 out_err:
 484         debugfs_remove_recursive(lkdtm_debugfs_root);
 485         return ret;
 486 }
 487
 488 static void __exit lkdtm_module_exit(void)
 489 {
 490         debugfs_remove_recursive(lkdtm_debugfs_root);
 491
 492         /* Handle test-specific clean-up. */
 493         lkdtm_usercopy_exit();
 494
 495         if (lkdtm_kprobe != NULL)
 496                 unregister_kprobe(lkdtm_kprobe);
 497
 498         pr_info("Crash point unregistered\n");
 499 }
 500
 501 module_init(lkdtm_module_init);
 502 module_exit(lkdtm_module_exit);
 503
 504 MODULE_LICENSE("GPL");
 505 MODULE_DESCRIPTION("Kernel crash testing module");