drivers/misc/lkdtm.c

   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 #include <linux/vmalloc.h>
  47
  48 #ifdef CONFIG_IDE
  49 #include <linux/ide.h>
  50 #endif
  51
  52 /*
  53  * Make sure our attempts to over run the kernel stack doesn't trigger
  54  * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
  55  * recurse past the end of THREAD_SIZE by default.
  56  */
  57 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
  58 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
  59 #else
  60 #define REC_STACK_SIZE (THREAD_SIZE / 8)
  61 #endif
  62 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
  63
  64 #define DEFAULT_COUNT 10
  65 #define EXEC_SIZE 64
  66
  67 enum cname {
  68         CN_INVALID,
  69         CN_INT_HARDWARE_ENTRY,
  70         CN_INT_HW_IRQ_EN,
  71         CN_INT_TASKLET_ENTRY,
  72         CN_FS_DEVRW,
  73         CN_MEM_SWAPOUT,
  74         CN_TIMERADD,
  75         CN_SCSI_DISPATCH_CMD,
  76         CN_IDE_CORE_CP,
  77         CN_DIRECT,
  78 };
  79
  80 enum ctype {
  81         CT_NONE,
  82         CT_PANIC,
  83         CT_BUG,
  84         CT_WARNING,
  85         CT_EXCEPTION,
  86         CT_LOOP,
  87         CT_OVERFLOW,
  88         CT_CORRUPT_STACK,
  89         CT_UNALIGNED_LOAD_STORE_WRITE,
  90         CT_OVERWRITE_ALLOCATION,
  91         CT_WRITE_AFTER_FREE,
  92         CT_SOFTLOCKUP,
  93         CT_HARDLOCKUP,
  94         CT_SPINLOCKUP,
  95         CT_HUNG_TASK,
  96         CT_EXEC_DATA,
  97         CT_EXEC_STACK,
  98         CT_EXEC_KMALLOC,
  99         CT_EXEC_VMALLOC,
 100 };
 101
 102 static char* cp_name[] = {
 103         "INT_HARDWARE_ENTRY",
 104         "INT_HW_IRQ_EN",
 105         "INT_TASKLET_ENTRY",
 106         "FS_DEVRW",
 107         "MEM_SWAPOUT",
 108         "TIMERADD",
 109         "SCSI_DISPATCH_CMD",
 110         "IDE_CORE_CP",
 111         "DIRECT",
 112 };
 113
 114 static char* cp_type[] = {
 115         "PANIC",
 116         "BUG",
 117         "WARNING",
 118         "EXCEPTION",
 119         "LOOP",
 120         "OVERFLOW",
 121         "CORRUPT_STACK",
 122         "UNALIGNED_LOAD_STORE_WRITE",
 123         "OVERWRITE_ALLOCATION",
 124         "WRITE_AFTER_FREE",
 125         "SOFTLOCKUP",
 126         "HARDLOCKUP",
 127         "SPINLOCKUP",
 128         "HUNG_TASK",
 129         "EXEC_DATA",
 130         "EXEC_STACK",
 131         "EXEC_KMALLOC",
 132         "EXEC_VMALLOC",
 133 };
 134
 135 static struct jprobe lkdtm;
 136
 137 static int lkdtm_parse_commandline(void);
 138 static void lkdtm_handler(void);
 139
 140 static char* cpoint_name;
 141 static char* cpoint_type;
 142 static int cpoint_count = DEFAULT_COUNT;
 143 static int recur_count = REC_NUM_DEFAULT;
 144
 145 static enum cname cpoint = CN_INVALID;
 146 static enum ctype cptype = CT_NONE;
 147 static int count = DEFAULT_COUNT;
 148 static DEFINE_SPINLOCK(count_lock);
 149 static DEFINE_SPINLOCK(lock_me_up);
 150
 151 static u8 data_area[EXEC_SIZE];
 152
 153 module_param(recur_count, int, 0644);
 154 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 155 module_param(cpoint_name, charp, 0444);
 156 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 157 module_param(cpoint_type, charp, 0444);
 158 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 159                                 "hitting the crash point");
 160 module_param(cpoint_count, int, 0644);
 161 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 162                                 "crash point is to be hit to trigger action");
 163
 164 static unsigned int jp_do_irq(unsigned int irq)
 165 {
 166         lkdtm_handler();
 167         jprobe_return();
 168         return 0;
 169 }
 170
 171 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 172                                        struct irqaction *action)
 173 {
 174         lkdtm_handler();
 175         jprobe_return();
 176         return 0;
 177 }
 178
 179 static void jp_tasklet_action(struct softirq_action *a)
 180 {
 181         lkdtm_handler();
 182         jprobe_return();
 183 }
 184
 185 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 186 {
 187         lkdtm_handler();
 188         jprobe_return();
 189 }
 190
 191 struct scan_control;
 192
 193 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 194                                              struct zone *zone,
 195                                              struct scan_control *sc)
 196 {
 197         lkdtm_handler();
 198         jprobe_return();
 199         return 0;
 200 }
 201
 202 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 203                             const enum hrtimer_mode mode)
 204 {
 205         lkdtm_handler();
 206         jprobe_return();
 207         return 0;
 208 }
 209
 210 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 211 {
 212         lkdtm_handler();
 213         jprobe_return();
 214         return 0;
 215 }
 216
 217 #ifdef CONFIG_IDE
 218 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 219                         struct block_device *bdev, unsigned int cmd,
 220                         unsigned long arg)
 221 {
 222         lkdtm_handler();
 223         jprobe_return();
 224         return 0;
 225 }
 226 #endif
 227
 228 /* Return the crashpoint number or NONE if the name is invalid */
 229 static enum ctype parse_cp_type(const char *what, size_t count)
 230 {
 231         int i;
 232
 233         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 234                 if (!strcmp(what, cp_type[i]))
 235                         return i + 1;
 236         }
 237
 238         return CT_NONE;
 239 }
 240
 241 static const char *cp_type_to_str(enum ctype type)
 242 {
 243         if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 244                 return "None";
 245
 246         return cp_type[type - 1];
 247 }
 248
 249 static const char *cp_name_to_str(enum cname name)
 250 {
 251         if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 252                 return "INVALID";
 253
 254         return cp_name[name - 1];
 255 }
 256
 257
 258 static int lkdtm_parse_commandline(void)
 259 {
 260         int i;
 261         unsigned long flags;
 262
 263         if (cpoint_count < 1 || recur_count < 1)
 264                 return -EINVAL;
 265
 266         spin_lock_irqsave(&count_lock, flags);
 267         count = cpoint_count;
 268         spin_unlock_irqrestore(&count_lock, flags);
 269
 270         /* No special parameters */
 271         if (!cpoint_type && !cpoint_name)
 272                 return 0;
 273
 274         /* Neither or both of these need to be set */
 275         if (!cpoint_type || !cpoint_name)
 276                 return -EINVAL;
 277
 278         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 279         if (cptype == CT_NONE)
 280                 return -EINVAL;
 281
 282         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 283                 if (!strcmp(cpoint_name, cp_name[i])) {
 284                         cpoint = i + 1;
 285                         return 0;
 286                 }
 287         }
 288
 289         /* Could not find a valid crash point */
 290         return -EINVAL;
 291 }
 292
 293 static int recursive_loop(int remaining)
 294 {
 295         char buf[REC_STACK_SIZE];
 296
 297         /* Make sure compiler does not optimize this away. */
 298         memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
 299         if (!remaining)
 300                 return 0;
 301         else
 302                 return recursive_loop(remaining - 1);
 303 }
 304
 305 static void do_nothing(void)
 306 {
 307         return;
 308 }
 309
 310 static noinline void corrupt_stack(void)
 311 {
 312         /* Use default char array length that triggers stack protection. */
 313         char data[8];
 314
 315         memset((void *)data, 0, 64);
 316 }
 317
 318 static void execute_location(void *dst)
 319 {
 320         void (*func)(void) = dst;
 321
 322         memcpy(dst, do_nothing, EXEC_SIZE);
 323         func();
 324 }
 325
 326 static void lkdtm_do_action(enum ctype which)
 327 {
 328         switch (which) {
 329         case CT_PANIC:
 330                 panic("dumptest");
 331                 break;
 332         case CT_BUG:
 333                 BUG();
 334                 break;
 335         case CT_WARNING:
 336                 WARN_ON(1);
 337                 break;
 338         case CT_EXCEPTION:
 339                 *((int *) 0) = 0;
 340                 break;
 341         case CT_LOOP:
 342                 for (;;)
 343                         ;
 344                 break;
 345         case CT_OVERFLOW:
 346                 (void) recursive_loop(recur_count);
 347                 break;
 348         case CT_CORRUPT_STACK:
 349                 corrupt_stack();
 350                 break;
 351         case CT_UNALIGNED_LOAD_STORE_WRITE: {
 352                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 353                                 3, 4, 5};
 354                 u32 *p;
 355                 u32 val = 0x12345678;
 356
 357                 p = (u32 *)(data + 1);
 358                 if (*p == 0)
 359                         val = 0x87654321;
 360                 *p = val;
 361                  break;
 362         }
 363         case CT_OVERWRITE_ALLOCATION: {
 364                 size_t len = 1020;
 365                 u32 *data = kmalloc(len, GFP_KERNEL);
 366
 367                 data[1024 / sizeof(u32)] = 0x12345678;
 368                 kfree(data);
 369                 break;
 370         }
 371         case CT_WRITE_AFTER_FREE: {
 372                 size_t len = 1024;
 373                 u32 *data = kmalloc(len, GFP_KERNEL);
 374
 375                 kfree(data);
 376                 schedule();
 377                 memset(data, 0x78, len);
 378                 break;
 379         }
 380         case CT_SOFTLOCKUP:
 381                 preempt_disable();
 382                 for (;;)
 383                         cpu_relax();
 384                 break;
 385         case CT_HARDLOCKUP:
 386                 local_irq_disable();
 387                 for (;;)
 388                         cpu_relax();
 389                 break;
 390         case CT_SPINLOCKUP:
 391                 /* Must be called twice to trigger. */
 392                 spin_lock(&lock_me_up);
 393                 break;
 394         case CT_HUNG_TASK:
 395                 set_current_state(TASK_UNINTERRUPTIBLE);
 396                 schedule();
 397                 break;
 398         case CT_EXEC_DATA:
 399                 execute_location(data_area);
 400                 break;
 401         case CT_EXEC_STACK: {
 402                 u8 stack_area[EXEC_SIZE];
 403                 execute_location(stack_area);
 404                 break;
 405         }
 406         case CT_EXEC_KMALLOC: {
 407                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 408                 execute_location(kmalloc_area);
 409                 kfree(kmalloc_area);
 410                 break;
 411         }
 412         case CT_EXEC_VMALLOC: {
 413                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 414                 execute_location(vmalloc_area);
 415                 vfree(vmalloc_area);
 416                 break;
 417         }
 418         case CT_NONE:
 419         default:
 420                 break;
 421         }
 422
 423 }
 424
 425 static void lkdtm_handler(void)
 426 {
 427         unsigned long flags;
 428         bool do_it = false;
 429
 430         spin_lock_irqsave(&count_lock, flags);
 431         count--;
 432         printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 433                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 434
 435         if (count == 0) {
 436                 do_it = true;
 437                 count = cpoint_count;
 438         }
 439         spin_unlock_irqrestore(&count_lock, flags);
 440
 441         if (do_it)
 442                 lkdtm_do_action(cptype);
 443 }
 444
 445 static int lkdtm_register_cpoint(enum cname which)
 446 {
 447         int ret;
 448
 449         cpoint = CN_INVALID;
 450         if (lkdtm.entry != NULL)
 451                 unregister_jprobe(&lkdtm);
 452
 453         switch (which) {
 454         case CN_DIRECT:
 455                 lkdtm_do_action(cptype);
 456                 return 0;
 457         case CN_INT_HARDWARE_ENTRY:
 458                 lkdtm.kp.symbol_name = "do_IRQ";
 459                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 460                 break;
 461         case CN_INT_HW_IRQ_EN:
 462                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 463                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 464                 break;
 465         case CN_INT_TASKLET_ENTRY:
 466                 lkdtm.kp.symbol_name = "tasklet_action";
 467                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 468                 break;
 469         case CN_FS_DEVRW:
 470                 lkdtm.kp.symbol_name = "ll_rw_block";
 471                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 472                 break;
 473         case CN_MEM_SWAPOUT:
 474                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 475                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 476                 break;
 477         case CN_TIMERADD:
 478                 lkdtm.kp.symbol_name = "hrtimer_start";
 479                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 480                 break;
 481         case CN_SCSI_DISPATCH_CMD:
 482                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 483                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 484                 break;
 485         case CN_IDE_CORE_CP:
 486 #ifdef CONFIG_IDE
 487                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 488                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 489 #else
 490                 printk(KERN_INFO "lkdtm: Crash point not available\n");
 491                 return -EINVAL;
 492 #endif
 493                 break;
 494         default:
 495                 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
 496                 return -EINVAL;
 497         }
 498
 499         cpoint = which;
 500         if ((ret = register_jprobe(&lkdtm)) < 0) {
 501                 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
 502                 cpoint = CN_INVALID;
 503         }
 504
 505         return ret;
 506 }
 507
 508 static ssize_t do_register_entry(enum cname which, struct file *f,
 509                 const char __user *user_buf, size_t count, loff_t *off)
 510 {
 511         char *buf;
 512         int err;
 513
 514         if (count >= PAGE_SIZE)
 515                 return -EINVAL;
 516
 517         buf = (char *)__get_free_page(GFP_KERNEL);
 518         if (!buf)
 519                 return -ENOMEM;
 520         if (copy_from_user(buf, user_buf, count)) {
 521                 free_page((unsigned long) buf);
 522                 return -EFAULT;
 523         }
 524         /* NULL-terminate and remove enter */
 525         buf[count] = '\0';
 526         strim(buf);
 527
 528         cptype = parse_cp_type(buf, count);
 529         free_page((unsigned long) buf);
 530
 531         if (cptype == CT_NONE)
 532                 return -EINVAL;
 533
 534         err = lkdtm_register_cpoint(which);
 535         if (err < 0)
 536                 return err;
 537
 538         *off += count;
 539
 540         return count;
 541 }
 542
 543 /* Generic read callback that just prints out the available crash types */
 544 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 545                 size_t count, loff_t *off)
 546 {
 547         char *buf;
 548         int i, n, out;
 549
 550         buf = (char *)__get_free_page(GFP_KERNEL);
 551         if (buf == NULL)
 552                 return -ENOMEM;
 553
 554         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 555         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 556                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 557         buf[n] = '\0';
 558
 559         out = simple_read_from_buffer(user_buf, count, off,
 560                                       buf, n);
 561         free_page((unsigned long) buf);
 562
 563         return out;
 564 }
 565
 566 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 567 {
 568         return 0;
 569 }
 570
 571
 572 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 573                 size_t count, loff_t *off)
 574 {
 575         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 576 }
 577
 578 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 579                 size_t count, loff_t *off)
 580 {
 581         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 582 }
 583
 584 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 585                 size_t count, loff_t *off)
 586 {
 587         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 588 }
 589
 590 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 591                 size_t count, loff_t *off)
 592 {
 593         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 594 }
 595
 596 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 597                 size_t count, loff_t *off)
 598 {
 599         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 600 }
 601
 602 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 603                 size_t count, loff_t *off)
 604 {
 605         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 606 }
 607
 608 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 609                 const char __user *buf, size_t count, loff_t *off)
 610 {
 611         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 612 }
 613
 614 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 615                 size_t count, loff_t *off)
 616 {
 617         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 618 }
 619
 620 /* Special entry to just crash directly. Available without KPROBEs */
 621 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 622                 size_t count, loff_t *off)
 623 {
 624         enum ctype type;
 625         char *buf;
 626
 627         if (count >= PAGE_SIZE)
 628                 return -EINVAL;
 629         if (count < 1)
 630                 return -EINVAL;
 631
 632         buf = (char *)__get_free_page(GFP_KERNEL);
 633         if (!buf)
 634                 return -ENOMEM;
 635         if (copy_from_user(buf, user_buf, count)) {
 636                 free_page((unsigned long) buf);
 637                 return -EFAULT;
 638         }
 639         /* NULL-terminate and remove enter */
 640         buf[count] = '\0';
 641         strim(buf);
 642
 643         type = parse_cp_type(buf, count);
 644         free_page((unsigned long) buf);
 645         if (type == CT_NONE)
 646                 return -EINVAL;
 647
 648         printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
 649                         cp_type_to_str(type));
 650         lkdtm_do_action(type);
 651         *off += count;
 652
 653         return count;
 654 }
 655
 656 struct crash_entry {
 657         const char *name;
 658         const struct file_operations fops;
 659 };
 660
 661 static const struct crash_entry crash_entries[] = {
 662         {"DIRECT", {.read = lkdtm_debugfs_read,
 663                         .llseek = generic_file_llseek,
 664                         .open = lkdtm_debugfs_open,
 665                         .write = direct_entry} },
 666         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 667                         .llseek = generic_file_llseek,
 668                         .open = lkdtm_debugfs_open,
 669                         .write = int_hardware_entry} },
 670         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 671                         .llseek = generic_file_llseek,
 672                         .open = lkdtm_debugfs_open,
 673                         .write = int_hw_irq_en} },
 674         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 675                         .llseek = generic_file_llseek,
 676                         .open = lkdtm_debugfs_open,
 677                         .write = int_tasklet_entry} },
 678         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 679                         .llseek = generic_file_llseek,
 680                         .open = lkdtm_debugfs_open,
 681                         .write = fs_devrw_entry} },
 682         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 683                         .llseek = generic_file_llseek,
 684                         .open = lkdtm_debugfs_open,
 685                         .write = mem_swapout_entry} },
 686         {"TIMERADD", {.read = lkdtm_debugfs_read,
 687                         .llseek = generic_file_llseek,
 688                         .open = lkdtm_debugfs_open,
 689                         .write = timeradd_entry} },
 690         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 691                         .llseek = generic_file_llseek,
 692                         .open = lkdtm_debugfs_open,
 693                         .write = scsi_dispatch_cmd_entry} },
 694         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 695                         .llseek = generic_file_llseek,
 696                         .open = lkdtm_debugfs_open,
 697                         .write = ide_core_cp_entry} },
 698 };
 699
 700 static struct dentry *lkdtm_debugfs_root;
 701
 702 static int __init lkdtm_module_init(void)
 703 {
 704         int ret = -EINVAL;
 705         int n_debugfs_entries = 1; /* Assume only the direct entry */
 706         int i;
 707
 708         /* Register debugfs interface */
 709         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 710         if (!lkdtm_debugfs_root) {
 711                 printk(KERN_ERR "lkdtm: creating root dir failed\n");
 712                 return -ENODEV;
 713         }
 714
 715 #ifdef CONFIG_KPROBES
 716         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 717 #endif
 718
 719         for (i = 0; i < n_debugfs_entries; i++) {
 720                 const struct crash_entry *cur = &crash_entries[i];
 721                 struct dentry *de;
 722
 723                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 724                                 NULL, &cur->fops);
 725                 if (de == NULL) {
 726                         printk(KERN_ERR "lkdtm: could not create %s\n",
 727                                         cur->name);
 728                         goto out_err;
 729                 }
 730         }
 731
 732         if (lkdtm_parse_commandline() == -EINVAL) {
 733                 printk(KERN_INFO "lkdtm: Invalid command\n");
 734                 goto out_err;
 735         }
 736
 737         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 738                 ret = lkdtm_register_cpoint(cpoint);
 739                 if (ret < 0) {
 740                         printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
 741                                         cpoint);
 742                         goto out_err;
 743                 }
 744                 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
 745                                 cpoint_name, cpoint_type);
 746         } else {
 747                 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
 748         }
 749
 750         return 0;
 751
 752 out_err:
 753         debugfs_remove_recursive(lkdtm_debugfs_root);
 754         return ret;
 755 }
 756
 757 static void __exit lkdtm_module_exit(void)
 758 {
 759         debugfs_remove_recursive(lkdtm_debugfs_root);
 760
 761         unregister_jprobe(&lkdtm);
 762         printk(KERN_INFO "lkdtm: Crash point unregistered\n");
 763 }
 764
 765 module_init(lkdtm_module_init);
 766 module_exit(lkdtm_module_exit);
 767
 768 MODULE_LICENSE("GPL");