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   1 /*
   2  * Kprobe module for testing crash dumps
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright (C) IBM Corporation, 2006
  19  *
  20  * Author: Ankita Garg <ankita@in.ibm.com>
  21  *
  22  * This module induces system failures at predefined crashpoints to
  23  * evaluate the reliability of crash dumps obtained using different dumping
  24  * solutions.
  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
  34 #include <linux/kernel.h>
  35 #include <linux/fs.h>
  36 #include <linux/module.h>
  37 #include <linux/buffer_head.h>
  38 #include <linux/kprobes.h>
  39 #include <linux/list.h>
  40 #include <linux/init.h>
  41 #include <linux/interrupt.h>
  42 #include <linux/hrtimer.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 #define REC_NUM_DEFAULT 10
  52
  53 enum cname {
  54         INVALID,
  55         INT_HARDWARE_ENTRY,
  56         INT_HW_IRQ_EN,
  57         INT_TASKLET_ENTRY,
  58         FS_DEVRW,
  59         MEM_SWAPOUT,
  60         TIMERADD,
  61         SCSI_DISPATCH_CMD,
  62         IDE_CORE_CP,
  63         DIRECT,
  64 };
  65
  66 enum ctype {
  67         NONE,
  68         PANIC,
  69         BUG,
  70         EXCEPTION,
  71         LOOP,
  72         OVERFLOW,
  73         CORRUPT_STACK,
  74         UNALIGNED_LOAD_STORE_WRITE,
  75         OVERWRITE_ALLOCATION,
  76         WRITE_AFTER_FREE,
  77 };
  78
  79 static char* cp_name[] = {
  80         "INT_HARDWARE_ENTRY",
  81         "INT_HW_IRQ_EN",
  82         "INT_TASKLET_ENTRY",
  83         "FS_DEVRW",
  84         "MEM_SWAPOUT",
  85         "TIMERADD",
  86         "SCSI_DISPATCH_CMD",
  87         "IDE_CORE_CP",
  88         "DIRECT",
  89 };
  90
  91 static char* cp_type[] = {
  92         "PANIC",
  93         "BUG",
  94         "EXCEPTION",
  95         "LOOP",
  96         "OVERFLOW",
  97         "CORRUPT_STACK",
  98         "UNALIGNED_LOAD_STORE_WRITE",
  99         "OVERWRITE_ALLOCATION",
 100         "WRITE_AFTER_FREE",
 101 };
 102
 103 static struct jprobe lkdtm;
 104
 105 static int lkdtm_parse_commandline(void);
 106 static void lkdtm_handler(void);
 107
 108 static char* cpoint_name;
 109 static char* cpoint_type;
 110 static int cpoint_count = DEFAULT_COUNT;
 111 static int recur_count = REC_NUM_DEFAULT;
 112
 113 static enum cname cpoint = INVALID;
 114 static enum ctype cptype = NONE;
 115 static int count = DEFAULT_COUNT;
 116
 117 module_param(recur_count, int, 0644);
 118 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
 119                                  "default is 10");
 120 module_param(cpoint_name, charp, 0644);
 121 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 122 module_param(cpoint_type, charp, 0644);
 123 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 124                                 "hitting the crash point");
 125 module_param(cpoint_count, int, 0644);
 126 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 127                                 "crash point is to be hit to trigger action");
 128
 129 static unsigned int jp_do_irq(unsigned int irq)
 130 {
 131         lkdtm_handler();
 132         jprobe_return();
 133         return 0;
 134 }
 135
 136 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 137                                        struct irqaction *action)
 138 {
 139         lkdtm_handler();
 140         jprobe_return();
 141         return 0;
 142 }
 143
 144 static void jp_tasklet_action(struct softirq_action *a)
 145 {
 146         lkdtm_handler();
 147         jprobe_return();
 148 }
 149
 150 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 151 {
 152         lkdtm_handler();
 153         jprobe_return();
 154 }
 155
 156 struct scan_control;
 157
 158 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 159                                              struct zone *zone,
 160                                              struct scan_control *sc)
 161 {
 162         lkdtm_handler();
 163         jprobe_return();
 164         return 0;
 165 }
 166
 167 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 168                             const enum hrtimer_mode mode)
 169 {
 170         lkdtm_handler();
 171         jprobe_return();
 172         return 0;
 173 }
 174
 175 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 176 {
 177         lkdtm_handler();
 178         jprobe_return();
 179         return 0;
 180 }
 181
 182 #ifdef CONFIG_IDE
 183 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 184                         struct block_device *bdev, unsigned int cmd,
 185                         unsigned long arg)
 186 {
 187         lkdtm_handler();
 188         jprobe_return();
 189         return 0;
 190 }
 191 #endif
 192
 193 /* Return the crashpoint number or NONE if the name is invalid */
 194 static enum ctype parse_cp_type(const char *what, size_t count)
 195 {
 196         int i;
 197
 198         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 199                 if (!strcmp(what, cp_type[i]))
 200                         return i + 1;
 201         }
 202
 203         return NONE;
 204 }
 205
 206 static const char *cp_type_to_str(enum ctype type)
 207 {
 208         if (type == NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 209                 return "None";
 210
 211         return cp_type[type - 1];
 212 }
 213
 214 static const char *cp_name_to_str(enum cname name)
 215 {
 216         if (name == INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 217                 return "INVALID";
 218
 219         return cp_name[name - 1];
 220 }
 221
 222
 223 static int lkdtm_parse_commandline(void)
 224 {
 225         int i;
 226
 227         if (cpoint_count < 1 || recur_count < 1)
 228                 return -EINVAL;
 229
 230         count = cpoint_count;
 231
 232         /* No special parameters */
 233         if (!cpoint_type && !cpoint_name)
 234                 return 0;
 235
 236         /* Neither or both of these need to be set */
 237         if (!cpoint_type || !cpoint_name)
 238                 return -EINVAL;
 239
 240         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 241         if (cptype == NONE)
 242                 return -EINVAL;
 243
 244         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 245                 if (!strcmp(cpoint_name, cp_name[i])) {
 246                         cpoint = i + 1;
 247                         return 0;
 248                 }
 249         }
 250
 251         /* Could not find a valid crash point */
 252         return -EINVAL;
 253 }
 254
 255 static int recursive_loop(int a)
 256 {
 257         char buf[1024];
 258
 259         memset(buf,0xFF,1024);
 260         recur_count--;
 261         if (!recur_count)
 262                 return 0;
 263         else
 264                 return recursive_loop(a);
 265 }
 266
 267 static void lkdtm_do_action(enum ctype which)
 268 {
 269         switch (which) {
 270         case PANIC:
 271                 panic("dumptest");
 272                 break;
 273         case BUG:
 274                 BUG();
 275                 break;
 276         case EXCEPTION:
 277                 *((int *) 0) = 0;
 278                 break;
 279         case LOOP:
 280                 for (;;)
 281                         ;
 282                 break;
 283         case OVERFLOW:
 284                 (void) recursive_loop(0);
 285                 break;
 286         case CORRUPT_STACK: {
 287                 volatile u32 data[8];
 288                 volatile u32 *p = data;
 289
 290                 p[12] = 0x12345678;
 291                 break;
 292         }
 293         case UNALIGNED_LOAD_STORE_WRITE: {
 294                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 295                                 3, 4, 5};
 296                 u32 *p;
 297                 u32 val = 0x12345678;
 298
 299                 p = (u32 *)(data + 1);
 300                 if (*p == 0)
 301                         val = 0x87654321;
 302                 *p = val;
 303                  break;
 304         }
 305         case OVERWRITE_ALLOCATION: {
 306                 size_t len = 1020;
 307                 u32 *data = kmalloc(len, GFP_KERNEL);
 308
 309                 data[1024 / sizeof(u32)] = 0x12345678;
 310                 kfree(data);
 311                 break;
 312         }
 313         case WRITE_AFTER_FREE: {
 314                 size_t len = 1024;
 315                 u32 *data = kmalloc(len, GFP_KERNEL);
 316
 317                 kfree(data);
 318                 schedule();
 319                 memset(data, 0x78, len);
 320                 break;
 321         }
 322         case NONE:
 323         default:
 324                 break;
 325         }
 326
 327 }
 328
 329 static void lkdtm_handler(void)
 330 {
 331         count--;
 332         printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 333                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 334
 335         if (count == 0) {
 336                 lkdtm_do_action(cptype);
 337                 count = cpoint_count;
 338         }
 339 }
 340
 341 static int lkdtm_register_cpoint(enum cname which)
 342 {
 343         int ret;
 344
 345         cpoint = INVALID;
 346         if (lkdtm.entry != NULL)
 347                 unregister_jprobe(&lkdtm);
 348
 349         switch (which) {
 350         case DIRECT:
 351                 lkdtm_do_action(cptype);
 352                 return 0;
 353         case INT_HARDWARE_ENTRY:
 354                 lkdtm.kp.symbol_name = "do_IRQ";
 355                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 356                 break;
 357         case INT_HW_IRQ_EN:
 358                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 359                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 360                 break;
 361         case INT_TASKLET_ENTRY:
 362                 lkdtm.kp.symbol_name = "tasklet_action";
 363                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 364                 break;
 365         case FS_DEVRW:
 366                 lkdtm.kp.symbol_name = "ll_rw_block";
 367                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 368                 break;
 369         case MEM_SWAPOUT:
 370                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 371                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 372                 break;
 373         case TIMERADD:
 374                 lkdtm.kp.symbol_name = "hrtimer_start";
 375                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 376                 break;
 377         case SCSI_DISPATCH_CMD:
 378                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 379                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 380                 break;
 381         case IDE_CORE_CP:
 382 #ifdef CONFIG_IDE
 383                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 384                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 385 #else
 386                 printk(KERN_INFO "lkdtm: Crash point not available\n");
 387                 return -EINVAL;
 388 #endif
 389                 break;
 390         default:
 391                 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
 392                 return -EINVAL;
 393         }
 394
 395         cpoint = which;
 396         if ((ret = register_jprobe(&lkdtm)) < 0) {
 397                 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
 398                 cpoint = INVALID;
 399         }
 400
 401         return ret;
 402 }
 403
 404 static ssize_t do_register_entry(enum cname which, struct file *f,
 405                 const char __user *user_buf, size_t count, loff_t *off)
 406 {
 407         char *buf;
 408         int err;
 409
 410         if (count >= PAGE_SIZE)
 411                 return -EINVAL;
 412
 413         buf = (char *)__get_free_page(GFP_KERNEL);
 414         if (!buf)
 415                 return -ENOMEM;
 416         if (copy_from_user(buf, user_buf, count)) {
 417                 free_page((unsigned long) buf);
 418                 return -EFAULT;
 419         }
 420         /* NULL-terminate and remove enter */
 421         buf[count] = '\0';
 422         strim(buf);
 423
 424         cptype = parse_cp_type(buf, count);
 425         free_page((unsigned long) buf);
 426
 427         if (cptype == NONE)
 428                 return -EINVAL;
 429
 430         err = lkdtm_register_cpoint(which);
 431         if (err < 0)
 432                 return err;
 433
 434         *off += count;
 435
 436         return count;
 437 }
 438
 439 /* Generic read callback that just prints out the available crash types */
 440 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 441                 size_t count, loff_t *off)
 442 {
 443         char *buf;
 444         int i, n, out;
 445
 446         buf = (char *)__get_free_page(GFP_KERNEL);
 447
 448         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 449         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 450                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 451         buf[n] = '\0';
 452
 453         out = simple_read_from_buffer(user_buf, count, off,
 454                                       buf, n);
 455         free_page((unsigned long) buf);
 456
 457         return out;
 458 }
 459
 460 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 461 {
 462         return 0;
 463 }
 464
 465
 466 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 467                 size_t count, loff_t *off)
 468 {
 469         return do_register_entry(INT_HARDWARE_ENTRY, f, buf, count, off);
 470 }
 471
 472 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 473                 size_t count, loff_t *off)
 474 {
 475         return do_register_entry(INT_HW_IRQ_EN, f, buf, count, off);
 476 }
 477
 478 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 479                 size_t count, loff_t *off)
 480 {
 481         return do_register_entry(INT_TASKLET_ENTRY, f, buf, count, off);
 482 }
 483
 484 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 485                 size_t count, loff_t *off)
 486 {
 487         return do_register_entry(FS_DEVRW, f, buf, count, off);
 488 }
 489
 490 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 491                 size_t count, loff_t *off)
 492 {
 493         return do_register_entry(MEM_SWAPOUT, f, buf, count, off);
 494 }
 495
 496 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 497                 size_t count, loff_t *off)
 498 {
 499         return do_register_entry(TIMERADD, f, buf, count, off);
 500 }
 501
 502 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 503                 const char __user *buf, size_t count, loff_t *off)
 504 {
 505         return do_register_entry(SCSI_DISPATCH_CMD, f, buf, count, off);
 506 }
 507
 508 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 509                 size_t count, loff_t *off)
 510 {
 511         return do_register_entry(IDE_CORE_CP, f, buf, count, off);
 512 }
 513
 514 /* Special entry to just crash directly. Available without KPROBEs */
 515 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 516                 size_t count, loff_t *off)
 517 {
 518         enum ctype type;
 519         char *buf;
 520
 521         if (count >= PAGE_SIZE)
 522                 return -EINVAL;
 523         if (count < 1)
 524                 return -EINVAL;
 525
 526         buf = (char *)__get_free_page(GFP_KERNEL);
 527         if (!buf)
 528                 return -ENOMEM;
 529         if (copy_from_user(buf, user_buf, count)) {
 530                 free_page((unsigned long) buf);
 531                 return -EFAULT;
 532         }
 533         /* NULL-terminate and remove enter */
 534         buf[count] = '\0';
 535         strim(buf);
 536
 537         type = parse_cp_type(buf, count);
 538         free_page((unsigned long) buf);
 539         if (type == NONE)
 540                 return -EINVAL;
 541
 542         printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
 543                         cp_type_to_str(type));
 544         lkdtm_do_action(type);
 545         *off += count;
 546
 547         return count;
 548 }
 549
 550 struct crash_entry {
 551         const char *name;
 552         const struct file_operations fops;
 553 };
 554
 555 static const struct crash_entry crash_entries[] = {
 556         {"DIRECT", {.read = lkdtm_debugfs_read,
 557                         .open = lkdtm_debugfs_open,
 558                         .write = direct_entry} },
 559         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 560                         .open = lkdtm_debugfs_open,
 561                         .write = int_hardware_entry} },
 562         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 563                         .open = lkdtm_debugfs_open,
 564                         .write = int_hw_irq_en} },
 565         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 566                         .open = lkdtm_debugfs_open,
 567                         .write = int_tasklet_entry} },
 568         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 569                         .open = lkdtm_debugfs_open,
 570                         .write = fs_devrw_entry} },
 571         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 572                         .open = lkdtm_debugfs_open,
 573                         .write = mem_swapout_entry} },
 574         {"TIMERADD", {.read = lkdtm_debugfs_read,
 575                         .open = lkdtm_debugfs_open,
 576                         .write = timeradd_entry} },
 577         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 578                         .open = lkdtm_debugfs_open,
 579                         .write = scsi_dispatch_cmd_entry} },
 580         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 581                         .open = lkdtm_debugfs_open,
 582                         .write = ide_core_cp_entry} },
 583 };
 584
 585 static struct dentry *lkdtm_debugfs_root;
 586
 587 static int __init lkdtm_module_init(void)
 588 {
 589         int ret = -EINVAL;
 590         int n_debugfs_entries = 1; /* Assume only the direct entry */
 591         int i;
 592
 593         /* Register debugfs interface */
 594         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 595         if (!lkdtm_debugfs_root) {
 596                 printk(KERN_ERR "lkdtm: creating root dir failed\n");
 597                 return -ENODEV;
 598         }
 599
 600 #ifdef CONFIG_KPROBES
 601         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 602 #endif
 603
 604         for (i = 0; i < n_debugfs_entries; i++) {
 605                 const struct crash_entry *cur = &crash_entries[i];
 606                 struct dentry *de;
 607
 608                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 609                                 NULL, &cur->fops);
 610                 if (de == NULL) {
 611                         printk(KERN_ERR "lkdtm: could not create %s\n",
 612                                         cur->name);
 613                         goto out_err;
 614                 }
 615         }
 616
 617         if (lkdtm_parse_commandline() == -EINVAL) {
 618                 printk(KERN_INFO "lkdtm: Invalid command\n");
 619                 goto out_err;
 620         }
 621
 622         if (cpoint != INVALID && cptype != NONE) {
 623                 ret = lkdtm_register_cpoint(cpoint);
 624                 if (ret < 0) {
 625                         printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
 626                                         cpoint);
 627                         goto out_err;
 628                 }
 629                 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
 630                                 cpoint_name, cpoint_type);
 631         } else {
 632                 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
 633         }
 634
 635         return 0;
 636
 637 out_err:
 638         debugfs_remove_recursive(lkdtm_debugfs_root);
 639         return ret;
 640 }
 641
 642 static void __exit lkdtm_module_exit(void)
 643 {
 644         debugfs_remove_recursive(lkdtm_debugfs_root);
 645
 646         unregister_jprobe(&lkdtm);
 647         printk(KERN_INFO "lkdtm: Crash point unregistered\n");
 648 }
 649
 650 module_init(lkdtm_module_init);
 651 module_exit(lkdtm_module_exit);
 652
 653 MODULE_LICENSE("GPL");