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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 <linux/slab.h>
  44 #include <scsi/scsi_cmnd.h>
  45 #include <linux/debugfs.h>
  46
  47 #ifdef CONFIG_IDE
  48 #include <linux/ide.h>
  49 #endif
  50
  51 #define DEFAULT_COUNT 10
  52 #define REC_NUM_DEFAULT 10
  53
  54 enum cname {
  55         INVALID,
  56         INT_HARDWARE_ENTRY,
  57         INT_HW_IRQ_EN,
  58         INT_TASKLET_ENTRY,
  59         FS_DEVRW,
  60         MEM_SWAPOUT,
  61         TIMERADD,
  62         SCSI_DISPATCH_CMD,
  63         IDE_CORE_CP,
  64         DIRECT,
  65 };
  66
  67 enum ctype {
  68         NONE,
  69         PANIC,
  70         BUG,
  71         EXCEPTION,
  72         LOOP,
  73         OVERFLOW,
  74         CORRUPT_STACK,
  75         UNALIGNED_LOAD_STORE_WRITE,
  76         OVERWRITE_ALLOCATION,
  77         WRITE_AFTER_FREE,
  78 };
  79
  80 static char* cp_name[] = {
  81         "INT_HARDWARE_ENTRY",
  82         "INT_HW_IRQ_EN",
  83         "INT_TASKLET_ENTRY",
  84         "FS_DEVRW",
  85         "MEM_SWAPOUT",
  86         "TIMERADD",
  87         "SCSI_DISPATCH_CMD",
  88         "IDE_CORE_CP",
  89         "DIRECT",
  90 };
  91
  92 static char* cp_type[] = {
  93         "PANIC",
  94         "BUG",
  95         "EXCEPTION",
  96         "LOOP",
  97         "OVERFLOW",
  98         "CORRUPT_STACK",
  99         "UNALIGNED_LOAD_STORE_WRITE",
 100         "OVERWRITE_ALLOCATION",
 101         "WRITE_AFTER_FREE",
 102 };
 103
 104 static struct jprobe lkdtm;
 105
 106 static int lkdtm_parse_commandline(void);
 107 static void lkdtm_handler(void);
 108
 109 static char* cpoint_name;
 110 static char* cpoint_type;
 111 static int cpoint_count = DEFAULT_COUNT;
 112 static int recur_count = REC_NUM_DEFAULT;
 113
 114 static enum cname cpoint = INVALID;
 115 static enum ctype cptype = NONE;
 116 static int count = DEFAULT_COUNT;
 117
 118 module_param(recur_count, int, 0644);
 119 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
 120                                  "default is 10");
 121 module_param(cpoint_name, charp, 0644);
 122 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 123 module_param(cpoint_type, charp, 0644);
 124 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 125                                 "hitting the crash point");
 126 module_param(cpoint_count, int, 0644);
 127 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 128                                 "crash point is to be hit to trigger action");
 129
 130 static unsigned int jp_do_irq(unsigned int irq)
 131 {
 132         lkdtm_handler();
 133         jprobe_return();
 134         return 0;
 135 }
 136
 137 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 138                                        struct irqaction *action)
 139 {
 140         lkdtm_handler();
 141         jprobe_return();
 142         return 0;
 143 }
 144
 145 static void jp_tasklet_action(struct softirq_action *a)
 146 {
 147         lkdtm_handler();
 148         jprobe_return();
 149 }
 150
 151 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 152 {
 153         lkdtm_handler();
 154         jprobe_return();
 155 }
 156
 157 struct scan_control;
 158
 159 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 160                                              struct zone *zone,
 161                                              struct scan_control *sc)
 162 {
 163         lkdtm_handler();
 164         jprobe_return();
 165         return 0;
 166 }
 167
 168 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 169                             const enum hrtimer_mode mode)
 170 {
 171         lkdtm_handler();
 172         jprobe_return();
 173         return 0;
 174 }
 175
 176 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 177 {
 178         lkdtm_handler();
 179         jprobe_return();
 180         return 0;
 181 }
 182
 183 #ifdef CONFIG_IDE
 184 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 185                         struct block_device *bdev, unsigned int cmd,
 186                         unsigned long arg)
 187 {
 188         lkdtm_handler();
 189         jprobe_return();
 190         return 0;
 191 }
 192 #endif
 193
 194 /* Return the crashpoint number or NONE if the name is invalid */
 195 static enum ctype parse_cp_type(const char *what, size_t count)
 196 {
 197         int i;
 198
 199         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 200                 if (!strcmp(what, cp_type[i]))
 201                         return i + 1;
 202         }
 203
 204         return NONE;
 205 }
 206
 207 static const char *cp_type_to_str(enum ctype type)
 208 {
 209         if (type == NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 210                 return "None";
 211
 212         return cp_type[type - 1];
 213 }
 214
 215 static const char *cp_name_to_str(enum cname name)
 216 {
 217         if (name == INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 218                 return "INVALID";
 219
 220         return cp_name[name - 1];
 221 }
 222
 223
 224 static int lkdtm_parse_commandline(void)
 225 {
 226         int i;
 227
 228         if (cpoint_count < 1 || recur_count < 1)
 229                 return -EINVAL;
 230
 231         count = cpoint_count;
 232
 233         /* No special parameters */
 234         if (!cpoint_type && !cpoint_name)
 235                 return 0;
 236
 237         /* Neither or both of these need to be set */
 238         if (!cpoint_type || !cpoint_name)
 239                 return -EINVAL;
 240
 241         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 242         if (cptype == NONE)
 243                 return -EINVAL;
 244
 245         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 246                 if (!strcmp(cpoint_name, cp_name[i])) {
 247                         cpoint = i + 1;
 248                         return 0;
 249                 }
 250         }
 251
 252         /* Could not find a valid crash point */
 253         return -EINVAL;
 254 }
 255
 256 static int recursive_loop(int a)
 257 {
 258         char buf[1024];
 259
 260         memset(buf,0xFF,1024);
 261         recur_count--;
 262         if (!recur_count)
 263                 return 0;
 264         else
 265                 return recursive_loop(a);
 266 }
 267
 268 static void lkdtm_do_action(enum ctype which)
 269 {
 270         switch (which) {
 271         case PANIC:
 272                 panic("dumptest");
 273                 break;
 274         case BUG:
 275                 BUG();
 276                 break;
 277         case EXCEPTION:
 278                 *((int *) 0) = 0;
 279                 break;
 280         case LOOP:
 281                 for (;;)
 282                         ;
 283                 break;
 284         case OVERFLOW:
 285                 (void) recursive_loop(0);
 286                 break;
 287         case CORRUPT_STACK: {
 288                 volatile u32 data[8];
 289                 volatile u32 *p = data;
 290
 291                 p[12] = 0x12345678;
 292                 break;
 293         }
 294         case UNALIGNED_LOAD_STORE_WRITE: {
 295                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 296                                 3, 4, 5};
 297                 u32 *p;
 298                 u32 val = 0x12345678;
 299
 300                 p = (u32 *)(data + 1);
 301                 if (*p == 0)
 302                         val = 0x87654321;
 303                 *p = val;
 304                  break;
 305         }
 306         case OVERWRITE_ALLOCATION: {
 307                 size_t len = 1020;
 308                 u32 *data = kmalloc(len, GFP_KERNEL);
 309
 310                 data[1024 / sizeof(u32)] = 0x12345678;
 311                 kfree(data);
 312                 break;
 313         }
 314         case WRITE_AFTER_FREE: {
 315                 size_t len = 1024;
 316                 u32 *data = kmalloc(len, GFP_KERNEL);
 317
 318                 kfree(data);
 319                 schedule();
 320                 memset(data, 0x78, len);
 321                 break;
 322         }
 323         case NONE:
 324         default:
 325                 break;
 326         }
 327
 328 }
 329
 330 static void lkdtm_handler(void)
 331 {
 332         count--;
 333         printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 334                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 335
 336         if (count == 0) {
 337                 lkdtm_do_action(cptype);
 338                 count = cpoint_count;
 339         }
 340 }
 341
 342 static int lkdtm_register_cpoint(enum cname which)
 343 {
 344         int ret;
 345
 346         cpoint = INVALID;
 347         if (lkdtm.entry != NULL)
 348                 unregister_jprobe(&lkdtm);
 349
 350         switch (which) {
 351         case DIRECT:
 352                 lkdtm_do_action(cptype);
 353                 return 0;
 354         case INT_HARDWARE_ENTRY:
 355                 lkdtm.kp.symbol_name = "do_IRQ";
 356                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 357                 break;
 358         case INT_HW_IRQ_EN:
 359                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 360                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 361                 break;
 362         case INT_TASKLET_ENTRY:
 363                 lkdtm.kp.symbol_name = "tasklet_action";
 364                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 365                 break;
 366         case FS_DEVRW:
 367                 lkdtm.kp.symbol_name = "ll_rw_block";
 368                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 369                 break;
 370         case MEM_SWAPOUT:
 371                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 372                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 373                 break;
 374         case TIMERADD:
 375                 lkdtm.kp.symbol_name = "hrtimer_start";
 376                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 377                 break;
 378         case SCSI_DISPATCH_CMD:
 379                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 380                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 381                 break;
 382         case IDE_CORE_CP:
 383 #ifdef CONFIG_IDE
 384                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 385                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 386 #else
 387                 printk(KERN_INFO "lkdtm: Crash point not available\n");
 388                 return -EINVAL;
 389 #endif
 390                 break;
 391         default:
 392                 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
 393                 return -EINVAL;
 394         }
 395
 396         cpoint = which;
 397         if ((ret = register_jprobe(&lkdtm)) < 0) {
 398                 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
 399                 cpoint = INVALID;
 400         }
 401
 402         return ret;
 403 }
 404
 405 static ssize_t do_register_entry(enum cname which, struct file *f,
 406                 const char __user *user_buf, size_t count, loff_t *off)
 407 {
 408         char *buf;
 409         int err;
 410
 411         if (count >= PAGE_SIZE)
 412                 return -EINVAL;
 413
 414         buf = (char *)__get_free_page(GFP_KERNEL);
 415         if (!buf)
 416                 return -ENOMEM;
 417         if (copy_from_user(buf, user_buf, count)) {
 418                 free_page((unsigned long) buf);
 419                 return -EFAULT;
 420         }
 421         /* NULL-terminate and remove enter */
 422         buf[count] = '\0';
 423         strim(buf);
 424
 425         cptype = parse_cp_type(buf, count);
 426         free_page((unsigned long) buf);
 427
 428         if (cptype == NONE)
 429                 return -EINVAL;
 430
 431         err = lkdtm_register_cpoint(which);
 432         if (err < 0)
 433                 return err;
 434
 435         *off += count;
 436
 437         return count;
 438 }
 439
 440 /* Generic read callback that just prints out the available crash types */
 441 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 442                 size_t count, loff_t *off)
 443 {
 444         char *buf;
 445         int i, n, out;
 446
 447         buf = (char *)__get_free_page(GFP_KERNEL);
 448
 449         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 450         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 451                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 452         buf[n] = '\0';
 453
 454         out = simple_read_from_buffer(user_buf, count, off,
 455                                       buf, n);
 456         free_page((unsigned long) buf);
 457
 458         return out;
 459 }
 460
 461 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 462 {
 463         return 0;
 464 }
 465
 466
 467 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 468                 size_t count, loff_t *off)
 469 {
 470         return do_register_entry(INT_HARDWARE_ENTRY, f, buf, count, off);
 471 }
 472
 473 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 474                 size_t count, loff_t *off)
 475 {
 476         return do_register_entry(INT_HW_IRQ_EN, f, buf, count, off);
 477 }
 478
 479 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 480                 size_t count, loff_t *off)
 481 {
 482         return do_register_entry(INT_TASKLET_ENTRY, f, buf, count, off);
 483 }
 484
 485 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 486                 size_t count, loff_t *off)
 487 {
 488         return do_register_entry(FS_DEVRW, f, buf, count, off);
 489 }
 490
 491 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 492                 size_t count, loff_t *off)
 493 {
 494         return do_register_entry(MEM_SWAPOUT, f, buf, count, off);
 495 }
 496
 497 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 498                 size_t count, loff_t *off)
 499 {
 500         return do_register_entry(TIMERADD, f, buf, count, off);
 501 }
 502
 503 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 504                 const char __user *buf, size_t count, loff_t *off)
 505 {
 506         return do_register_entry(SCSI_DISPATCH_CMD, f, buf, count, off);
 507 }
 508
 509 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 510                 size_t count, loff_t *off)
 511 {
 512         return do_register_entry(IDE_CORE_CP, f, buf, count, off);
 513 }
 514
 515 /* Special entry to just crash directly. Available without KPROBEs */
 516 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 517                 size_t count, loff_t *off)
 518 {
 519         enum ctype type;
 520         char *buf;
 521
 522         if (count >= PAGE_SIZE)
 523                 return -EINVAL;
 524         if (count < 1)
 525                 return -EINVAL;
 526
 527         buf = (char *)__get_free_page(GFP_KERNEL);
 528         if (!buf)
 529                 return -ENOMEM;
 530         if (copy_from_user(buf, user_buf, count)) {
 531                 free_page((unsigned long) buf);
 532                 return -EFAULT;
 533         }
 534         /* NULL-terminate and remove enter */
 535         buf[count] = '\0';
 536         strim(buf);
 537
 538         type = parse_cp_type(buf, count);
 539         free_page((unsigned long) buf);
 540         if (type == NONE)
 541                 return -EINVAL;
 542
 543         printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
 544                         cp_type_to_str(type));
 545         lkdtm_do_action(type);
 546         *off += count;
 547
 548         return count;
 549 }
 550
 551 struct crash_entry {
 552         const char *name;
 553         const struct file_operations fops;
 554 };
 555
 556 static const struct crash_entry crash_entries[] = {
 557         {"DIRECT", {.read = lkdtm_debugfs_read,
 558                         .open = lkdtm_debugfs_open,
 559                         .write = direct_entry} },
 560         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 561                         .open = lkdtm_debugfs_open,
 562                         .write = int_hardware_entry} },
 563         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 564                         .open = lkdtm_debugfs_open,
 565                         .write = int_hw_irq_en} },
 566         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 567                         .open = lkdtm_debugfs_open,
 568                         .write = int_tasklet_entry} },
 569         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 570                         .open = lkdtm_debugfs_open,
 571                         .write = fs_devrw_entry} },
 572         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 573                         .open = lkdtm_debugfs_open,
 574                         .write = mem_swapout_entry} },
 575         {"TIMERADD", {.read = lkdtm_debugfs_read,
 576                         .open = lkdtm_debugfs_open,
 577                         .write = timeradd_entry} },
 578         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 579                         .open = lkdtm_debugfs_open,
 580                         .write = scsi_dispatch_cmd_entry} },
 581         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 582                         .open = lkdtm_debugfs_open,
 583                         .write = ide_core_cp_entry} },
 584 };
 585
 586 static struct dentry *lkdtm_debugfs_root;
 587
 588 static int __init lkdtm_module_init(void)
 589 {
 590         int ret = -EINVAL;
 591         int n_debugfs_entries = 1; /* Assume only the direct entry */
 592         int i;
 593
 594         /* Register debugfs interface */
 595         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 596         if (!lkdtm_debugfs_root) {
 597                 printk(KERN_ERR "lkdtm: creating root dir failed\n");
 598                 return -ENODEV;
 599         }
 600
 601 #ifdef CONFIG_KPROBES
 602         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 603 #endif
 604
 605         for (i = 0; i < n_debugfs_entries; i++) {
 606                 const struct crash_entry *cur = &crash_entries[i];
 607                 struct dentry *de;
 608
 609                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 610                                 NULL, &cur->fops);
 611                 if (de == NULL) {
 612                         printk(KERN_ERR "lkdtm: could not create %s\n",
 613                                         cur->name);
 614                         goto out_err;
 615                 }
 616         }
 617
 618         if (lkdtm_parse_commandline() == -EINVAL) {
 619                 printk(KERN_INFO "lkdtm: Invalid command\n");
 620                 goto out_err;
 621         }
 622
 623         if (cpoint != INVALID && cptype != NONE) {
 624                 ret = lkdtm_register_cpoint(cpoint);
 625                 if (ret < 0) {
 626                         printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
 627                                         cpoint);
 628                         goto out_err;
 629                 }
 630                 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
 631                                 cpoint_name, cpoint_type);
 632         } else {
 633                 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
 634         }
 635
 636         return 0;
 637
 638 out_err:
 639         debugfs_remove_recursive(lkdtm_debugfs_root);
 640         return ret;
 641 }
 642
 643 static void __exit lkdtm_module_exit(void)
 644 {
 645         debugfs_remove_recursive(lkdtm_debugfs_root);
 646
 647         unregister_jprobe(&lkdtm);
 648         printk(KERN_INFO "lkdtm: Crash point unregistered\n");
 649 }
 650
 651 module_init(lkdtm_module_init);
 652 module_exit(lkdtm_module_exit);
 653
 654 MODULE_LICENSE("GPL");