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 void lkdtm_handler(void);
  60 static ssize_t lkdtm_debugfs_entry(struct file *f,
  61                                    const char __user *user_buf,
  62                                    size_t count, loff_t *off);
  63
  64
  65 /* jprobe entry point handlers. */
  66 static unsigned int jp_do_irq(unsigned int irq)
  67 {
  68         lkdtm_handler();
  69         jprobe_return();
  70         return 0;
  71 }
  72
  73 static irqreturn_t jp_handle_irq_event(unsigned int irq,
  74                                        struct irqaction *action)
  75 {
  76         lkdtm_handler();
  77         jprobe_return();
  78         return 0;
  79 }
  80
  81 static void jp_tasklet_action(struct softirq_action *a)
  82 {
  83         lkdtm_handler();
  84         jprobe_return();
  85 }
  86
  87 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
  88 {
  89         lkdtm_handler();
  90         jprobe_return();
  91 }
  92
  93 struct scan_control;
  94
  95 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
  96                                              struct zone *zone,
  97                                              struct scan_control *sc)
  98 {
  99         lkdtm_handler();
 100         jprobe_return();
 101         return 0;
 102 }
 103
 104 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 105                             const enum hrtimer_mode mode)
 106 {
 107         lkdtm_handler();
 108         jprobe_return();
 109         return 0;
 110 }
 111
 112 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 113 {
 114         lkdtm_handler();
 115         jprobe_return();
 116         return 0;
 117 }
 118
 119 # ifdef CONFIG_IDE
 120 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 121                         struct block_device *bdev, unsigned int cmd,
 122                         unsigned long arg)
 123 {
 124         lkdtm_handler();
 125         jprobe_return();
 126         return 0;
 127 }
 128 # endif
 129 #endif
 130
 131 /* Crash points */
 132 struct crashpoint {
 133         const char *name;
 134         const struct file_operations fops;
 135         struct jprobe jprobe;
 136 };
 137
 138 #define CRASHPOINT(_name, _write, _symbol, _entry)              \
 139         {                                                       \
 140                 .name = _name,                                  \
 141                 .fops = {                                       \
 142                         .read   = lkdtm_debugfs_read,           \
 143                         .llseek = generic_file_llseek,          \
 144                         .open   = lkdtm_debugfs_open,           \
 145                         .write  = _write,                       \
 146                 },                                              \
 147                 .jprobe = {                                     \
 148                         .kp.symbol_name = _symbol,              \
 149                         .entry = (kprobe_opcode_t *)_entry,     \
 150                 },                                              \
 151         }
 152
 153 /* Define the possible places where we can trigger a crash point. */
 154 struct crashpoint crashpoints[] = {
 155         CRASHPOINT("DIRECT",                    direct_entry,
 156                    NULL,                        NULL),
 157 #ifdef CONFIG_KPROBES
 158         CRASHPOINT("INT_HARDWARE_ENTRY",        lkdtm_debugfs_entry,
 159                    "do_IRQ",                    jp_do_irq),
 160         CRASHPOINT("INT_HW_IRQ_EN",             lkdtm_debugfs_entry,
 161                    "handle_IRQ_event",          jp_handle_irq_event),
 162         CRASHPOINT("INT_TASKLET_ENTRY",         lkdtm_debugfs_entry,
 163                    "tasklet_action",            jp_tasklet_action),
 164         CRASHPOINT("FS_DEVRW",                  lkdtm_debugfs_entry,
 165                    "ll_rw_block",               jp_ll_rw_block),
 166         CRASHPOINT("MEM_SWAPOUT",               lkdtm_debugfs_entry,
 167                    "shrink_inactive_list",      jp_shrink_inactive_list),
 168         CRASHPOINT("TIMERADD",                  lkdtm_debugfs_entry,
 169                    "hrtimer_start",             jp_hrtimer_start),
 170         CRASHPOINT("SCSI_DISPATCH_CMD",         lkdtm_debugfs_entry,
 171                    "scsi_dispatch_cmd",         jp_scsi_dispatch_cmd),
 172 # ifdef CONFIG_IDE
 173         CRASHPOINT("IDE_CORE_CP",               lkdtm_debugfs_entry,
 174                    "generic_ide_ioctl",         jp_generic_ide_ioctl),
 175 # endif
 176 #endif
 177 };
 178
 179
 180 /* Crash types. */
 181 struct crashtype {
 182         const char *name;
 183         void (*func)(void);
 184 };
 185
 186 #define CRASHTYPE(_name)                        \
 187         {                                       \
 188                 .name = __stringify(_name),     \
 189                 .func = lkdtm_ ## _name,        \
 190         }
 191
 192 /* Define the possible types of crashes that can be triggered. */
 193 struct crashtype crashtypes[] = {
 194         CRASHTYPE(PANIC),
 195         CRASHTYPE(BUG),
 196         CRASHTYPE(WARNING),
 197         CRASHTYPE(EXCEPTION),
 198         CRASHTYPE(LOOP),
 199         CRASHTYPE(OVERFLOW),
 200         CRASHTYPE(CORRUPT_LIST_ADD),
 201         CRASHTYPE(CORRUPT_LIST_DEL),
 202         CRASHTYPE(CORRUPT_USER_DS),
 203         CRASHTYPE(CORRUPT_STACK),
 204         CRASHTYPE(CORRUPT_STACK_STRONG),
 205         CRASHTYPE(STACK_GUARD_PAGE_LEADING),
 206         CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
 207         CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
 208         CRASHTYPE(OVERWRITE_ALLOCATION),
 209         CRASHTYPE(WRITE_AFTER_FREE),
 210         CRASHTYPE(READ_AFTER_FREE),
 211         CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
 212         CRASHTYPE(READ_BUDDY_AFTER_FREE),
 213         CRASHTYPE(SOFTLOCKUP),
 214         CRASHTYPE(HARDLOCKUP),
 215         CRASHTYPE(SPINLOCKUP),
 216         CRASHTYPE(HUNG_TASK),
 217         CRASHTYPE(EXEC_DATA),
 218         CRASHTYPE(EXEC_STACK),
 219         CRASHTYPE(EXEC_KMALLOC),
 220         CRASHTYPE(EXEC_VMALLOC),
 221         CRASHTYPE(EXEC_RODATA),
 222         CRASHTYPE(EXEC_USERSPACE),
 223         CRASHTYPE(EXEC_NULL),
 224         CRASHTYPE(ACCESS_USERSPACE),
 225         CRASHTYPE(ACCESS_NULL),
 226         CRASHTYPE(WRITE_RO),
 227         CRASHTYPE(WRITE_RO_AFTER_INIT),
 228         CRASHTYPE(WRITE_KERN),
 229         CRASHTYPE(REFCOUNT_INC_OVERFLOW),
 230         CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
 231         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
 232         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
 233         CRASHTYPE(REFCOUNT_DEC_ZERO),
 234         CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
 235         CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
 236         CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
 237         CRASHTYPE(REFCOUNT_INC_ZERO),
 238         CRASHTYPE(REFCOUNT_ADD_ZERO),
 239         CRASHTYPE(REFCOUNT_INC_SATURATED),
 240         CRASHTYPE(REFCOUNT_DEC_SATURATED),
 241         CRASHTYPE(REFCOUNT_ADD_SATURATED),
 242         CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
 243         CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
 244         CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
 245         CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
 246         CRASHTYPE(REFCOUNT_TIMING),
 247         CRASHTYPE(ATOMIC_TIMING),
 248         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
 249         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
 250         CRASHTYPE(USERCOPY_HEAP_FLAG_TO),
 251         CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
 252         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 253         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 254         CRASHTYPE(USERCOPY_STACK_BEYOND),
 255         CRASHTYPE(USERCOPY_KERNEL),
 256 };
 257
 258
 259 /* Global jprobe entry and crashtype. */
 260 static struct jprobe *lkdtm_jprobe;
 261 struct crashpoint *lkdtm_crashpoint;
 262 struct crashtype *lkdtm_crashtype;
 263
 264 /* Module parameters */
 265 static int recur_count = -1;
 266 module_param(recur_count, int, 0644);
 267 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 268
 269 static char* cpoint_name;
 270 module_param(cpoint_name, charp, 0444);
 271 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 272
 273 static char* cpoint_type;
 274 module_param(cpoint_type, charp, 0444);
 275 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 276                                 "hitting the crash point");
 277
 278 static int cpoint_count = DEFAULT_COUNT;
 279 module_param(cpoint_count, int, 0644);
 280 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 281                                 "crash point is to be hit to trigger action");
 282
 283
 284 /* Return the crashtype number or NULL if the name is invalid */
 285 static struct crashtype *find_crashtype(const char *name)
 286 {
 287         int i;
 288
 289         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 290                 if (!strcmp(name, crashtypes[i].name))
 291                         return &crashtypes[i];
 292         }
 293
 294         return NULL;
 295 }
 296
 297 /*
 298  * This is forced noinline just so it distinctly shows up in the stackdump
 299  * which makes validation of expected lkdtm crashes easier.
 300  */
 301 static noinline void lkdtm_do_action(struct crashtype *crashtype)
 302 {
 303         BUG_ON(!crashtype || !crashtype->func);
 304         crashtype->func();
 305 }
 306
 307 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 308                                  struct crashtype *crashtype)
 309 {
 310         int ret;
 311
 312         /* If this doesn't have a symbol, just call immediately. */
 313         if (!crashpoint->jprobe.kp.symbol_name) {
 314                 lkdtm_do_action(crashtype);
 315                 return 0;
 316         }
 317
 318         if (lkdtm_jprobe != NULL)
 319                 unregister_jprobe(lkdtm_jprobe);
 320
 321         lkdtm_crashpoint = crashpoint;
 322         lkdtm_crashtype = crashtype;
 323         lkdtm_jprobe = &crashpoint->jprobe;
 324         ret = register_jprobe(lkdtm_jprobe);
 325         if (ret < 0) {
 326                 pr_info("Couldn't register jprobe %s\n",
 327                         crashpoint->jprobe.kp.symbol_name);
 328                 lkdtm_jprobe = NULL;
 329                 lkdtm_crashpoint = NULL;
 330                 lkdtm_crashtype = NULL;
 331         }
 332
 333         return ret;
 334 }
 335
 336 #ifdef CONFIG_KPROBES
 337 /* Global crash counter and spinlock. */
 338 static int crash_count = DEFAULT_COUNT;
 339 static DEFINE_SPINLOCK(crash_count_lock);
 340
 341 /* Called by jprobe entry points. */
 342 static void lkdtm_handler(void)
 343 {
 344         unsigned long flags;
 345         bool do_it = false;
 346
 347         BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
 348
 349         spin_lock_irqsave(&crash_count_lock, flags);
 350         crash_count--;
 351         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 352                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
 353
 354         if (crash_count == 0) {
 355                 do_it = true;
 356                 crash_count = cpoint_count;
 357         }
 358         spin_unlock_irqrestore(&crash_count_lock, flags);
 359
 360         if (do_it)
 361                 lkdtm_do_action(lkdtm_crashtype);
 362 }
 363
 364 static ssize_t lkdtm_debugfs_entry(struct file *f,
 365                                    const char __user *user_buf,
 366                                    size_t count, loff_t *off)
 367 {
 368         struct crashpoint *crashpoint = file_inode(f)->i_private;
 369         struct crashtype *crashtype = NULL;
 370         char *buf;
 371         int err;
 372
 373         if (count >= PAGE_SIZE)
 374                 return -EINVAL;
 375
 376         buf = (char *)__get_free_page(GFP_KERNEL);
 377         if (!buf)
 378                 return -ENOMEM;
 379         if (copy_from_user(buf, user_buf, count)) {
 380                 free_page((unsigned long) buf);
 381                 return -EFAULT;
 382         }
 383         /* NULL-terminate and remove enter */
 384         buf[count] = '\0';
 385         strim(buf);
 386
 387         crashtype = find_crashtype(buf);
 388         free_page((unsigned long)buf);
 389
 390         if (!crashtype)
 391                 return -EINVAL;
 392
 393         err = lkdtm_register_cpoint(crashpoint, crashtype);
 394         if (err < 0)
 395                 return err;
 396
 397         *off += count;
 398
 399         return count;
 400 }
 401 #endif
 402
 403 /* Generic read callback that just prints out the available crash types */
 404 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 405                 size_t count, loff_t *off)
 406 {
 407         char *buf;
 408         int i, n, out;
 409
 410         buf = (char *)__get_free_page(GFP_KERNEL);
 411         if (buf == NULL)
 412                 return -ENOMEM;
 413
 414         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 415         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 416                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
 417                               crashtypes[i].name);
 418         }
 419         buf[n] = '\0';
 420
 421         out = simple_read_from_buffer(user_buf, count, off,
 422                                       buf, n);
 423         free_page((unsigned long) buf);
 424
 425         return out;
 426 }
 427
 428 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 429 {
 430         return 0;
 431 }
 432
 433 /* Special entry to just crash directly. Available without KPROBEs */
 434 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 435                 size_t count, loff_t *off)
 436 {
 437         struct crashtype *crashtype;
 438         char *buf;
 439
 440         if (count >= PAGE_SIZE)
 441                 return -EINVAL;
 442         if (count < 1)
 443                 return -EINVAL;
 444
 445         buf = (char *)__get_free_page(GFP_KERNEL);
 446         if (!buf)
 447                 return -ENOMEM;
 448         if (copy_from_user(buf, user_buf, count)) {
 449                 free_page((unsigned long) buf);
 450                 return -EFAULT;
 451         }
 452         /* NULL-terminate and remove enter */
 453         buf[count] = '\0';
 454         strim(buf);
 455
 456         crashtype = find_crashtype(buf);
 457         free_page((unsigned long) buf);
 458         if (!crashtype)
 459                 return -EINVAL;
 460
 461         pr_info("Performing direct entry %s\n", crashtype->name);
 462         lkdtm_do_action(crashtype);
 463         *off += count;
 464
 465         return count;
 466 }
 467
 468 static struct dentry *lkdtm_debugfs_root;
 469
 470 static int __init lkdtm_module_init(void)
 471 {
 472         struct crashpoint *crashpoint = NULL;
 473         struct crashtype *crashtype = NULL;
 474         int ret = -EINVAL;
 475         int i;
 476
 477         /* Neither or both of these need to be set */
 478         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
 479                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
 480                 return -EINVAL;
 481         }
 482
 483         if (cpoint_type) {
 484                 crashtype = find_crashtype(cpoint_type);
 485                 if (!crashtype) {
 486                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
 487                         return -EINVAL;
 488                 }
 489         }
 490
 491         if (cpoint_name) {
 492                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 493                         if (!strcmp(cpoint_name, crashpoints[i].name))
 494                                 crashpoint = &crashpoints[i];
 495                 }
 496
 497                 /* Refuse unknown crashpoints. */
 498                 if (!crashpoint) {
 499                         pr_err("Invalid crashpoint %s\n", cpoint_name);
 500                         return -EINVAL;
 501                 }
 502         }
 503
 504 #ifdef CONFIG_KPROBES
 505         /* Set crash count. */
 506         crash_count = cpoint_count;
 507 #endif
 508
 509         /* Handle test-specific initialization. */
 510         lkdtm_bugs_init(&recur_count);
 511         lkdtm_perms_init();
 512         lkdtm_usercopy_init();
 513
 514         /* Register debugfs interface */
 515         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 516         if (!lkdtm_debugfs_root) {
 517                 pr_err("creating root dir failed\n");
 518                 return -ENODEV;
 519         }
 520
 521         /* Install debugfs trigger files. */
 522         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 523                 struct crashpoint *cur = &crashpoints[i];
 524                 struct dentry *de;
 525
 526                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 527                                          cur, &cur->fops);
 528                 if (de == NULL) {
 529                         pr_err("could not create crashpoint %s\n", cur->name);
 530                         goto out_err;
 531                 }
 532         }
 533
 534         /* Install crashpoint if one was selected. */
 535         if (crashpoint) {
 536                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
 537                 if (ret < 0) {
 538                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
 539                         goto out_err;
 540                 }
 541                 pr_info("Crash point %s of type %s registered\n",
 542                         crashpoint->name, cpoint_type);
 543         } else {
 544                 pr_info("No crash points registered, enable through debugfs\n");
 545         }
 546
 547         return 0;
 548
 549 out_err:
 550         debugfs_remove_recursive(lkdtm_debugfs_root);
 551         return ret;
 552 }
 553
 554 static void __exit lkdtm_module_exit(void)
 555 {
 556         debugfs_remove_recursive(lkdtm_debugfs_root);
 557
 558         /* Handle test-specific clean-up. */
 559         lkdtm_usercopy_exit();
 560
 561         if (lkdtm_jprobe != NULL)
 562                 unregister_jprobe(lkdtm_jprobe);
 563
 564         pr_info("Crash point unregistered\n");
 565 }
 566
 567 module_init(lkdtm_module_init);
 568 module_exit(lkdtm_module_exit);
 569
 570 MODULE_LICENSE("GPL");
 571 MODULE_DESCRIPTION("Kernel crash testing module");