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