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 noinline void corrupt_stack(void)
 301 {
 302         /* Use default char array length that triggers stack protection. */
 303         char data[8];
 304
 305         memset((void *)data, 0, 64);
 306 }
 307
 308 static void execute_location(void *dst)
 309 {
 310         void (*func)(void) = dst;
 311
 312         memcpy(dst, do_nothing, EXEC_SIZE);
 313         func();
 314 }
 315
 316 static void lkdtm_do_action(enum ctype which)
 317 {
 318         switch (which) {
 319         case CT_PANIC:
 320                 panic("dumptest");
 321                 break;
 322         case CT_BUG:
 323                 BUG();
 324                 break;
 325         case CT_WARNING:
 326                 WARN_ON(1);
 327                 break;
 328         case CT_EXCEPTION:
 329                 *((int *) 0) = 0;
 330                 break;
 331         case CT_LOOP:
 332                 for (;;)
 333                         ;
 334                 break;
 335         case CT_OVERFLOW:
 336                 (void) recursive_loop(0);
 337                 break;
 338         case CT_CORRUPT_STACK:
 339                 corrupt_stack();
 340                 break;
 341         case CT_UNALIGNED_LOAD_STORE_WRITE: {
 342                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 343                                 3, 4, 5};
 344                 u32 *p;
 345                 u32 val = 0x12345678;
 346
 347                 p = (u32 *)(data + 1);
 348                 if (*p == 0)
 349                         val = 0x87654321;
 350                 *p = val;
 351                  break;
 352         }
 353         case CT_OVERWRITE_ALLOCATION: {
 354                 size_t len = 1020;
 355                 u32 *data = kmalloc(len, GFP_KERNEL);
 356
 357                 data[1024 / sizeof(u32)] = 0x12345678;
 358                 kfree(data);
 359                 break;
 360         }
 361         case CT_WRITE_AFTER_FREE: {
 362                 size_t len = 1024;
 363                 u32 *data = kmalloc(len, GFP_KERNEL);
 364
 365                 kfree(data);
 366                 schedule();
 367                 memset(data, 0x78, len);
 368                 break;
 369         }
 370         case CT_SOFTLOCKUP:
 371                 preempt_disable();
 372                 for (;;)
 373                         cpu_relax();
 374                 break;
 375         case CT_HARDLOCKUP:
 376                 local_irq_disable();
 377                 for (;;)
 378                         cpu_relax();
 379                 break;
 380         case CT_SPINLOCKUP:
 381                 /* Must be called twice to trigger. */
 382                 spin_lock(&lock_me_up);
 383                 break;
 384         case CT_HUNG_TASK:
 385                 set_current_state(TASK_UNINTERRUPTIBLE);
 386                 schedule();
 387                 break;
 388         case CT_EXEC_DATA:
 389                 execute_location(data_area);
 390                 break;
 391         case CT_EXEC_STACK: {
 392                 u8 stack_area[EXEC_SIZE];
 393                 execute_location(stack_area);
 394                 break;
 395         }
 396         case CT_EXEC_KMALLOC: {
 397                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 398                 execute_location(kmalloc_area);
 399                 kfree(kmalloc_area);
 400                 break;
 401         }
 402         case CT_EXEC_VMALLOC: {
 403                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 404                 execute_location(vmalloc_area);
 405                 vfree(vmalloc_area);
 406                 break;
 407         }
 408         case CT_NONE:
 409         default:
 410                 break;
 411         }
 412
 413 }
 414
 415 static void lkdtm_handler(void)
 416 {
 417         unsigned long flags;
 418         bool do_it = false;
 419
 420         spin_lock_irqsave(&count_lock, flags);
 421         count--;
 422         printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 423                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 424
 425         if (count == 0) {
 426                 do_it = true;
 427                 count = cpoint_count;
 428         }
 429         spin_unlock_irqrestore(&count_lock, flags);
 430
 431         if (do_it)
 432                 lkdtm_do_action(cptype);
 433 }
 434
 435 static int lkdtm_register_cpoint(enum cname which)
 436 {
 437         int ret;
 438
 439         cpoint = CN_INVALID;
 440         if (lkdtm.entry != NULL)
 441                 unregister_jprobe(&lkdtm);
 442
 443         switch (which) {
 444         case CN_DIRECT:
 445                 lkdtm_do_action(cptype);
 446                 return 0;
 447         case CN_INT_HARDWARE_ENTRY:
 448                 lkdtm.kp.symbol_name = "do_IRQ";
 449                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 450                 break;
 451         case CN_INT_HW_IRQ_EN:
 452                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 453                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 454                 break;
 455         case CN_INT_TASKLET_ENTRY:
 456                 lkdtm.kp.symbol_name = "tasklet_action";
 457                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 458                 break;
 459         case CN_FS_DEVRW:
 460                 lkdtm.kp.symbol_name = "ll_rw_block";
 461                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 462                 break;
 463         case CN_MEM_SWAPOUT:
 464                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 465                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 466                 break;
 467         case CN_TIMERADD:
 468                 lkdtm.kp.symbol_name = "hrtimer_start";
 469                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 470                 break;
 471         case CN_SCSI_DISPATCH_CMD:
 472                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 473                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 474                 break;
 475         case CN_IDE_CORE_CP:
 476 #ifdef CONFIG_IDE
 477                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 478                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 479 #else
 480                 printk(KERN_INFO "lkdtm: Crash point not available\n");
 481                 return -EINVAL;
 482 #endif
 483                 break;
 484         default:
 485                 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
 486                 return -EINVAL;
 487         }
 488
 489         cpoint = which;
 490         if ((ret = register_jprobe(&lkdtm)) < 0) {
 491                 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
 492                 cpoint = CN_INVALID;
 493         }
 494
 495         return ret;
 496 }
 497
 498 static ssize_t do_register_entry(enum cname which, struct file *f,
 499                 const char __user *user_buf, size_t count, loff_t *off)
 500 {
 501         char *buf;
 502         int err;
 503
 504         if (count >= PAGE_SIZE)
 505                 return -EINVAL;
 506
 507         buf = (char *)__get_free_page(GFP_KERNEL);
 508         if (!buf)
 509                 return -ENOMEM;
 510         if (copy_from_user(buf, user_buf, count)) {
 511                 free_page((unsigned long) buf);
 512                 return -EFAULT;
 513         }
 514         /* NULL-terminate and remove enter */
 515         buf[count] = '\0';
 516         strim(buf);
 517
 518         cptype = parse_cp_type(buf, count);
 519         free_page((unsigned long) buf);
 520
 521         if (cptype == CT_NONE)
 522                 return -EINVAL;
 523
 524         err = lkdtm_register_cpoint(which);
 525         if (err < 0)
 526                 return err;
 527
 528         *off += count;
 529
 530         return count;
 531 }
 532
 533 /* Generic read callback that just prints out the available crash types */
 534 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 535                 size_t count, loff_t *off)
 536 {
 537         char *buf;
 538         int i, n, out;
 539
 540         buf = (char *)__get_free_page(GFP_KERNEL);
 541         if (buf == NULL)
 542                 return -ENOMEM;
 543
 544         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 545         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 546                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 547         buf[n] = '\0';
 548
 549         out = simple_read_from_buffer(user_buf, count, off,
 550                                       buf, n);
 551         free_page((unsigned long) buf);
 552
 553         return out;
 554 }
 555
 556 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 557 {
 558         return 0;
 559 }
 560
 561
 562 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 563                 size_t count, loff_t *off)
 564 {
 565         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 566 }
 567
 568 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 569                 size_t count, loff_t *off)
 570 {
 571         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 572 }
 573
 574 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 575                 size_t count, loff_t *off)
 576 {
 577         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 578 }
 579
 580 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 581                 size_t count, loff_t *off)
 582 {
 583         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 584 }
 585
 586 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 587                 size_t count, loff_t *off)
 588 {
 589         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 590 }
 591
 592 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 593                 size_t count, loff_t *off)
 594 {
 595         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 596 }
 597
 598 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 599                 const char __user *buf, size_t count, loff_t *off)
 600 {
 601         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 602 }
 603
 604 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 605                 size_t count, loff_t *off)
 606 {
 607         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 608 }
 609
 610 /* Special entry to just crash directly. Available without KPROBEs */
 611 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 612                 size_t count, loff_t *off)
 613 {
 614         enum ctype type;
 615         char *buf;
 616
 617         if (count >= PAGE_SIZE)
 618                 return -EINVAL;
 619         if (count < 1)
 620                 return -EINVAL;
 621
 622         buf = (char *)__get_free_page(GFP_KERNEL);
 623         if (!buf)
 624                 return -ENOMEM;
 625         if (copy_from_user(buf, user_buf, count)) {
 626                 free_page((unsigned long) buf);
 627                 return -EFAULT;
 628         }
 629         /* NULL-terminate and remove enter */
 630         buf[count] = '\0';
 631         strim(buf);
 632
 633         type = parse_cp_type(buf, count);
 634         free_page((unsigned long) buf);
 635         if (type == CT_NONE)
 636                 return -EINVAL;
 637
 638         printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
 639                         cp_type_to_str(type));
 640         lkdtm_do_action(type);
 641         *off += count;
 642
 643         return count;
 644 }
 645
 646 struct crash_entry {
 647         const char *name;
 648         const struct file_operations fops;
 649 };
 650
 651 static const struct crash_entry crash_entries[] = {
 652         {"DIRECT", {.read = lkdtm_debugfs_read,
 653                         .llseek = generic_file_llseek,
 654                         .open = lkdtm_debugfs_open,
 655                         .write = direct_entry} },
 656         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 657                         .llseek = generic_file_llseek,
 658                         .open = lkdtm_debugfs_open,
 659                         .write = int_hardware_entry} },
 660         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 661                         .llseek = generic_file_llseek,
 662                         .open = lkdtm_debugfs_open,
 663                         .write = int_hw_irq_en} },
 664         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 665                         .llseek = generic_file_llseek,
 666                         .open = lkdtm_debugfs_open,
 667                         .write = int_tasklet_entry} },
 668         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 669                         .llseek = generic_file_llseek,
 670                         .open = lkdtm_debugfs_open,
 671                         .write = fs_devrw_entry} },
 672         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 673                         .llseek = generic_file_llseek,
 674                         .open = lkdtm_debugfs_open,
 675                         .write = mem_swapout_entry} },
 676         {"TIMERADD", {.read = lkdtm_debugfs_read,
 677                         .llseek = generic_file_llseek,
 678                         .open = lkdtm_debugfs_open,
 679                         .write = timeradd_entry} },
 680         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 681                         .llseek = generic_file_llseek,
 682                         .open = lkdtm_debugfs_open,
 683                         .write = scsi_dispatch_cmd_entry} },
 684         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 685                         .llseek = generic_file_llseek,
 686                         .open = lkdtm_debugfs_open,
 687                         .write = ide_core_cp_entry} },
 688 };
 689
 690 static struct dentry *lkdtm_debugfs_root;
 691
 692 static int __init lkdtm_module_init(void)
 693 {
 694         int ret = -EINVAL;
 695         int n_debugfs_entries = 1; /* Assume only the direct entry */
 696         int i;
 697
 698         /* Register debugfs interface */
 699         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 700         if (!lkdtm_debugfs_root) {
 701                 printk(KERN_ERR "lkdtm: creating root dir failed\n");
 702                 return -ENODEV;
 703         }
 704
 705 #ifdef CONFIG_KPROBES
 706         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 707 #endif
 708
 709         for (i = 0; i < n_debugfs_entries; i++) {
 710                 const struct crash_entry *cur = &crash_entries[i];
 711                 struct dentry *de;
 712
 713                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 714                                 NULL, &cur->fops);
 715                 if (de == NULL) {
 716                         printk(KERN_ERR "lkdtm: could not create %s\n",
 717                                         cur->name);
 718                         goto out_err;
 719                 }
 720         }
 721
 722         if (lkdtm_parse_commandline() == -EINVAL) {
 723                 printk(KERN_INFO "lkdtm: Invalid command\n");
 724                 goto out_err;
 725         }
 726
 727         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 728                 ret = lkdtm_register_cpoint(cpoint);
 729                 if (ret < 0) {
 730                         printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
 731                                         cpoint);
 732                         goto out_err;
 733                 }
 734                 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
 735                                 cpoint_name, cpoint_type);
 736         } else {
 737                 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
 738         }
 739
 740         return 0;
 741
 742 out_err:
 743         debugfs_remove_recursive(lkdtm_debugfs_root);
 744         return ret;
 745 }
 746
 747 static void __exit lkdtm_module_exit(void)
 748 {
 749         debugfs_remove_recursive(lkdtm_debugfs_root);
 750
 751         unregister_jprobe(&lkdtm);
 752         printk(KERN_INFO "lkdtm: Crash point unregistered\n");
 753 }
 754
 755 module_init(lkdtm_module_init);
 756 module_exit(lkdtm_module_exit);
 757
 758 MODULE_LICENSE("GPL");