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