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 #include <linux/mman.h>
  48
  49 #ifdef CONFIG_IDE
  50 #include <linux/ide.h>
  51 #endif
  52
  53 /*
  54  * Make sure our attempts to over run the kernel stack doesn't trigger
  55  * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
  56  * recurse past the end of THREAD_SIZE by default.
  57  */
  58 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
  59 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
  60 #else
  61 #define REC_STACK_SIZE (THREAD_SIZE / 8)
  62 #endif
  63 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
  64
  65 #define DEFAULT_COUNT 10
  66 #define EXEC_SIZE 64
  67
  68 enum cname {
  69         CN_INVALID,
  70         CN_INT_HARDWARE_ENTRY,
  71         CN_INT_HW_IRQ_EN,
  72         CN_INT_TASKLET_ENTRY,
  73         CN_FS_DEVRW,
  74         CN_MEM_SWAPOUT,
  75         CN_TIMERADD,
  76         CN_SCSI_DISPATCH_CMD,
  77         CN_IDE_CORE_CP,
  78         CN_DIRECT,
  79 };
  80
  81 enum ctype {
  82         CT_NONE,
  83         CT_PANIC,
  84         CT_BUG,
  85         CT_WARNING,
  86         CT_EXCEPTION,
  87         CT_LOOP,
  88         CT_OVERFLOW,
  89         CT_CORRUPT_STACK,
  90         CT_UNALIGNED_LOAD_STORE_WRITE,
  91         CT_OVERWRITE_ALLOCATION,
  92         CT_WRITE_AFTER_FREE,
  93         CT_SOFTLOCKUP,
  94         CT_HARDLOCKUP,
  95         CT_SPINLOCKUP,
  96         CT_HUNG_TASK,
  97         CT_EXEC_DATA,
  98         CT_EXEC_STACK,
  99         CT_EXEC_KMALLOC,
 100         CT_EXEC_VMALLOC,
 101         CT_EXEC_USERSPACE,
 102         CT_ACCESS_USERSPACE,
 103         CT_WRITE_RO,
 104 };
 105
 106 static char* cp_name[] = {
 107         "INT_HARDWARE_ENTRY",
 108         "INT_HW_IRQ_EN",
 109         "INT_TASKLET_ENTRY",
 110         "FS_DEVRW",
 111         "MEM_SWAPOUT",
 112         "TIMERADD",
 113         "SCSI_DISPATCH_CMD",
 114         "IDE_CORE_CP",
 115         "DIRECT",
 116 };
 117
 118 static char* cp_type[] = {
 119         "PANIC",
 120         "BUG",
 121         "WARNING",
 122         "EXCEPTION",
 123         "LOOP",
 124         "OVERFLOW",
 125         "CORRUPT_STACK",
 126         "UNALIGNED_LOAD_STORE_WRITE",
 127         "OVERWRITE_ALLOCATION",
 128         "WRITE_AFTER_FREE",
 129         "SOFTLOCKUP",
 130         "HARDLOCKUP",
 131         "SPINLOCKUP",
 132         "HUNG_TASK",
 133         "EXEC_DATA",
 134         "EXEC_STACK",
 135         "EXEC_KMALLOC",
 136         "EXEC_VMALLOC",
 137         "EXEC_USERSPACE",
 138         "ACCESS_USERSPACE",
 139         "WRITE_RO",
 140 };
 141
 142 static struct jprobe lkdtm;
 143
 144 static int lkdtm_parse_commandline(void);
 145 static void lkdtm_handler(void);
 146
 147 static char* cpoint_name;
 148 static char* cpoint_type;
 149 static int cpoint_count = DEFAULT_COUNT;
 150 static int recur_count = REC_NUM_DEFAULT;
 151
 152 static enum cname cpoint = CN_INVALID;
 153 static enum ctype cptype = CT_NONE;
 154 static int count = DEFAULT_COUNT;
 155 static DEFINE_SPINLOCK(count_lock);
 156 static DEFINE_SPINLOCK(lock_me_up);
 157
 158 static u8 data_area[EXEC_SIZE];
 159
 160 static const unsigned long rodata = 0xAA55AA55;
 161
 162 module_param(recur_count, int, 0644);
 163 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 164 module_param(cpoint_name, charp, 0444);
 165 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 166 module_param(cpoint_type, charp, 0444);
 167 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 168                                 "hitting the crash point");
 169 module_param(cpoint_count, int, 0644);
 170 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 171                                 "crash point is to be hit to trigger action");
 172
 173 static unsigned int jp_do_irq(unsigned int irq)
 174 {
 175         lkdtm_handler();
 176         jprobe_return();
 177         return 0;
 178 }
 179
 180 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 181                                        struct irqaction *action)
 182 {
 183         lkdtm_handler();
 184         jprobe_return();
 185         return 0;
 186 }
 187
 188 static void jp_tasklet_action(struct softirq_action *a)
 189 {
 190         lkdtm_handler();
 191         jprobe_return();
 192 }
 193
 194 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 195 {
 196         lkdtm_handler();
 197         jprobe_return();
 198 }
 199
 200 struct scan_control;
 201
 202 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 203                                              struct zone *zone,
 204                                              struct scan_control *sc)
 205 {
 206         lkdtm_handler();
 207         jprobe_return();
 208         return 0;
 209 }
 210
 211 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 212                             const enum hrtimer_mode mode)
 213 {
 214         lkdtm_handler();
 215         jprobe_return();
 216         return 0;
 217 }
 218
 219 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 220 {
 221         lkdtm_handler();
 222         jprobe_return();
 223         return 0;
 224 }
 225
 226 #ifdef CONFIG_IDE
 227 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 228                         struct block_device *bdev, unsigned int cmd,
 229                         unsigned long arg)
 230 {
 231         lkdtm_handler();
 232         jprobe_return();
 233         return 0;
 234 }
 235 #endif
 236
 237 /* Return the crashpoint number or NONE if the name is invalid */
 238 static enum ctype parse_cp_type(const char *what, size_t count)
 239 {
 240         int i;
 241
 242         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 243                 if (!strcmp(what, cp_type[i]))
 244                         return i + 1;
 245         }
 246
 247         return CT_NONE;
 248 }
 249
 250 static const char *cp_type_to_str(enum ctype type)
 251 {
 252         if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 253                 return "None";
 254
 255         return cp_type[type - 1];
 256 }
 257
 258 static const char *cp_name_to_str(enum cname name)
 259 {
 260         if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 261                 return "INVALID";
 262
 263         return cp_name[name - 1];
 264 }
 265
 266
 267 static int lkdtm_parse_commandline(void)
 268 {
 269         int i;
 270         unsigned long flags;
 271
 272         if (cpoint_count < 1 || recur_count < 1)
 273                 return -EINVAL;
 274
 275         spin_lock_irqsave(&count_lock, flags);
 276         count = cpoint_count;
 277         spin_unlock_irqrestore(&count_lock, flags);
 278
 279         /* No special parameters */
 280         if (!cpoint_type && !cpoint_name)
 281                 return 0;
 282
 283         /* Neither or both of these need to be set */
 284         if (!cpoint_type || !cpoint_name)
 285                 return -EINVAL;
 286
 287         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 288         if (cptype == CT_NONE)
 289                 return -EINVAL;
 290
 291         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 292                 if (!strcmp(cpoint_name, cp_name[i])) {
 293                         cpoint = i + 1;
 294                         return 0;
 295                 }
 296         }
 297
 298         /* Could not find a valid crash point */
 299         return -EINVAL;
 300 }
 301
 302 static int recursive_loop(int remaining)
 303 {
 304         char buf[REC_STACK_SIZE];
 305
 306         /* Make sure compiler does not optimize this away. */
 307         memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
 308         if (!remaining)
 309                 return 0;
 310         else
 311                 return recursive_loop(remaining - 1);
 312 }
 313
 314 static void do_nothing(void)
 315 {
 316         return;
 317 }
 318
 319 static noinline void corrupt_stack(void)
 320 {
 321         /* Use default char array length that triggers stack protection. */
 322         char data[8];
 323
 324         memset((void *)data, 0, 64);
 325 }
 326
 327 static void execute_location(void *dst)
 328 {
 329         void (*func)(void) = dst;
 330
 331         memcpy(dst, do_nothing, EXEC_SIZE);
 332         func();
 333 }
 334
 335 static void execute_user_location(void *dst)
 336 {
 337         /* Intentionally crossing kernel/user memory boundary. */
 338         void (*func)(void) = dst;
 339
 340         if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
 341                 return;
 342         func();
 343 }
 344
 345 static void lkdtm_do_action(enum ctype which)
 346 {
 347         switch (which) {
 348         case CT_PANIC:
 349                 panic("dumptest");
 350                 break;
 351         case CT_BUG:
 352                 BUG();
 353                 break;
 354         case CT_WARNING:
 355                 WARN_ON(1);
 356                 break;
 357         case CT_EXCEPTION:
 358                 *((int *) 0) = 0;
 359                 break;
 360         case CT_LOOP:
 361                 for (;;)
 362                         ;
 363                 break;
 364         case CT_OVERFLOW:
 365                 (void) recursive_loop(recur_count);
 366                 break;
 367         case CT_CORRUPT_STACK:
 368                 corrupt_stack();
 369                 break;
 370         case CT_UNALIGNED_LOAD_STORE_WRITE: {
 371                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 372                                 3, 4, 5};
 373                 u32 *p;
 374                 u32 val = 0x12345678;
 375
 376                 p = (u32 *)(data + 1);
 377                 if (*p == 0)
 378                         val = 0x87654321;
 379                 *p = val;
 380                  break;
 381         }
 382         case CT_OVERWRITE_ALLOCATION: {
 383                 size_t len = 1020;
 384                 u32 *data = kmalloc(len, GFP_KERNEL);
 385
 386                 data[1024 / sizeof(u32)] = 0x12345678;
 387                 kfree(data);
 388                 break;
 389         }
 390         case CT_WRITE_AFTER_FREE: {
 391                 size_t len = 1024;
 392                 u32 *data = kmalloc(len, GFP_KERNEL);
 393
 394                 kfree(data);
 395                 schedule();
 396                 memset(data, 0x78, len);
 397                 break;
 398         }
 399         case CT_SOFTLOCKUP:
 400                 preempt_disable();
 401                 for (;;)
 402                         cpu_relax();
 403                 break;
 404         case CT_HARDLOCKUP:
 405                 local_irq_disable();
 406                 for (;;)
 407                         cpu_relax();
 408                 break;
 409         case CT_SPINLOCKUP:
 410                 /* Must be called twice to trigger. */
 411                 spin_lock(&lock_me_up);
 412                 /* Let sparse know we intended to exit holding the lock. */
 413                 __release(&lock_me_up);
 414                 break;
 415         case CT_HUNG_TASK:
 416                 set_current_state(TASK_UNINTERRUPTIBLE);
 417                 schedule();
 418                 break;
 419         case CT_EXEC_DATA:
 420                 execute_location(data_area);
 421                 break;
 422         case CT_EXEC_STACK: {
 423                 u8 stack_area[EXEC_SIZE];
 424                 execute_location(stack_area);
 425                 break;
 426         }
 427         case CT_EXEC_KMALLOC: {
 428                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 429                 execute_location(kmalloc_area);
 430                 kfree(kmalloc_area);
 431                 break;
 432         }
 433         case CT_EXEC_VMALLOC: {
 434                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 435                 execute_location(vmalloc_area);
 436                 vfree(vmalloc_area);
 437                 break;
 438         }
 439         case CT_EXEC_USERSPACE: {
 440                 unsigned long user_addr;
 441
 442                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 443                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 444                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 445                 if (user_addr >= TASK_SIZE) {
 446                         pr_warn("Failed to allocate user memory\n");
 447                         return;
 448                 }
 449                 execute_user_location((void *)user_addr);
 450                 vm_munmap(user_addr, PAGE_SIZE);
 451                 break;
 452         }
 453         case CT_ACCESS_USERSPACE: {
 454                 unsigned long user_addr, tmp;
 455                 unsigned long *ptr;
 456
 457                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 458                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 459                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 460                 if (user_addr >= TASK_SIZE) {
 461                         pr_warn("Failed to allocate user memory\n");
 462                         return;
 463                 }
 464
 465                 ptr = (unsigned long *)user_addr;
 466                 tmp = *ptr;
 467                 tmp += 0xc0dec0de;
 468                 *ptr = tmp;
 469
 470                 vm_munmap(user_addr, PAGE_SIZE);
 471
 472                 break;
 473         }
 474         case CT_WRITE_RO: {
 475                 unsigned long *ptr;
 476
 477                 ptr = (unsigned long *)&rodata;
 478                 *ptr ^= 0xabcd1234;
 479
 480                 break;
 481         }
 482         case CT_NONE:
 483         default:
 484                 break;
 485         }
 486
 487 }
 488
 489 static void lkdtm_handler(void)
 490 {
 491         unsigned long flags;
 492         bool do_it = false;
 493
 494         spin_lock_irqsave(&count_lock, flags);
 495         count--;
 496         printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 497                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 498
 499         if (count == 0) {
 500                 do_it = true;
 501                 count = cpoint_count;
 502         }
 503         spin_unlock_irqrestore(&count_lock, flags);
 504
 505         if (do_it)
 506                 lkdtm_do_action(cptype);
 507 }
 508
 509 static int lkdtm_register_cpoint(enum cname which)
 510 {
 511         int ret;
 512
 513         cpoint = CN_INVALID;
 514         if (lkdtm.entry != NULL)
 515                 unregister_jprobe(&lkdtm);
 516
 517         switch (which) {
 518         case CN_DIRECT:
 519                 lkdtm_do_action(cptype);
 520                 return 0;
 521         case CN_INT_HARDWARE_ENTRY:
 522                 lkdtm.kp.symbol_name = "do_IRQ";
 523                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 524                 break;
 525         case CN_INT_HW_IRQ_EN:
 526                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 527                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 528                 break;
 529         case CN_INT_TASKLET_ENTRY:
 530                 lkdtm.kp.symbol_name = "tasklet_action";
 531                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 532                 break;
 533         case CN_FS_DEVRW:
 534                 lkdtm.kp.symbol_name = "ll_rw_block";
 535                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 536                 break;
 537         case CN_MEM_SWAPOUT:
 538                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 539                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 540                 break;
 541         case CN_TIMERADD:
 542                 lkdtm.kp.symbol_name = "hrtimer_start";
 543                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 544                 break;
 545         case CN_SCSI_DISPATCH_CMD:
 546                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 547                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 548                 break;
 549         case CN_IDE_CORE_CP:
 550 #ifdef CONFIG_IDE
 551                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 552                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 553 #else
 554                 printk(KERN_INFO "lkdtm: Crash point not available\n");
 555                 return -EINVAL;
 556 #endif
 557                 break;
 558         default:
 559                 printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
 560                 return -EINVAL;
 561         }
 562
 563         cpoint = which;
 564         if ((ret = register_jprobe(&lkdtm)) < 0) {
 565                 printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
 566                 cpoint = CN_INVALID;
 567         }
 568
 569         return ret;
 570 }
 571
 572 static ssize_t do_register_entry(enum cname which, struct file *f,
 573                 const char __user *user_buf, size_t count, loff_t *off)
 574 {
 575         char *buf;
 576         int err;
 577
 578         if (count >= PAGE_SIZE)
 579                 return -EINVAL;
 580
 581         buf = (char *)__get_free_page(GFP_KERNEL);
 582         if (!buf)
 583                 return -ENOMEM;
 584         if (copy_from_user(buf, user_buf, count)) {
 585                 free_page((unsigned long) buf);
 586                 return -EFAULT;
 587         }
 588         /* NULL-terminate and remove enter */
 589         buf[count] = '\0';
 590         strim(buf);
 591
 592         cptype = parse_cp_type(buf, count);
 593         free_page((unsigned long) buf);
 594
 595         if (cptype == CT_NONE)
 596                 return -EINVAL;
 597
 598         err = lkdtm_register_cpoint(which);
 599         if (err < 0)
 600                 return err;
 601
 602         *off += count;
 603
 604         return count;
 605 }
 606
 607 /* Generic read callback that just prints out the available crash types */
 608 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 609                 size_t count, loff_t *off)
 610 {
 611         char *buf;
 612         int i, n, out;
 613
 614         buf = (char *)__get_free_page(GFP_KERNEL);
 615         if (buf == NULL)
 616                 return -ENOMEM;
 617
 618         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 619         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 620                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 621         buf[n] = '\0';
 622
 623         out = simple_read_from_buffer(user_buf, count, off,
 624                                       buf, n);
 625         free_page((unsigned long) buf);
 626
 627         return out;
 628 }
 629
 630 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 631 {
 632         return 0;
 633 }
 634
 635
 636 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 637                 size_t count, loff_t *off)
 638 {
 639         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 640 }
 641
 642 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 643                 size_t count, loff_t *off)
 644 {
 645         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 646 }
 647
 648 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 649                 size_t count, loff_t *off)
 650 {
 651         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 652 }
 653
 654 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 655                 size_t count, loff_t *off)
 656 {
 657         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 658 }
 659
 660 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 661                 size_t count, loff_t *off)
 662 {
 663         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 664 }
 665
 666 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 667                 size_t count, loff_t *off)
 668 {
 669         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 670 }
 671
 672 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 673                 const char __user *buf, size_t count, loff_t *off)
 674 {
 675         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 676 }
 677
 678 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 679                 size_t count, loff_t *off)
 680 {
 681         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 682 }
 683
 684 /* Special entry to just crash directly. Available without KPROBEs */
 685 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 686                 size_t count, loff_t *off)
 687 {
 688         enum ctype type;
 689         char *buf;
 690
 691         if (count >= PAGE_SIZE)
 692                 return -EINVAL;
 693         if (count < 1)
 694                 return -EINVAL;
 695
 696         buf = (char *)__get_free_page(GFP_KERNEL);
 697         if (!buf)
 698                 return -ENOMEM;
 699         if (copy_from_user(buf, user_buf, count)) {
 700                 free_page((unsigned long) buf);
 701                 return -EFAULT;
 702         }
 703         /* NULL-terminate and remove enter */
 704         buf[count] = '\0';
 705         strim(buf);
 706
 707         type = parse_cp_type(buf, count);
 708         free_page((unsigned long) buf);
 709         if (type == CT_NONE)
 710                 return -EINVAL;
 711
 712         printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
 713                         cp_type_to_str(type));
 714         lkdtm_do_action(type);
 715         *off += count;
 716
 717         return count;
 718 }
 719
 720 struct crash_entry {
 721         const char *name;
 722         const struct file_operations fops;
 723 };
 724
 725 static const struct crash_entry crash_entries[] = {
 726         {"DIRECT", {.read = lkdtm_debugfs_read,
 727                         .llseek = generic_file_llseek,
 728                         .open = lkdtm_debugfs_open,
 729                         .write = direct_entry} },
 730         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 731                         .llseek = generic_file_llseek,
 732                         .open = lkdtm_debugfs_open,
 733                         .write = int_hardware_entry} },
 734         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 735                         .llseek = generic_file_llseek,
 736                         .open = lkdtm_debugfs_open,
 737                         .write = int_hw_irq_en} },
 738         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 739                         .llseek = generic_file_llseek,
 740                         .open = lkdtm_debugfs_open,
 741                         .write = int_tasklet_entry} },
 742         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 743                         .llseek = generic_file_llseek,
 744                         .open = lkdtm_debugfs_open,
 745                         .write = fs_devrw_entry} },
 746         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 747                         .llseek = generic_file_llseek,
 748                         .open = lkdtm_debugfs_open,
 749                         .write = mem_swapout_entry} },
 750         {"TIMERADD", {.read = lkdtm_debugfs_read,
 751                         .llseek = generic_file_llseek,
 752                         .open = lkdtm_debugfs_open,
 753                         .write = timeradd_entry} },
 754         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 755                         .llseek = generic_file_llseek,
 756                         .open = lkdtm_debugfs_open,
 757                         .write = scsi_dispatch_cmd_entry} },
 758         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 759                         .llseek = generic_file_llseek,
 760                         .open = lkdtm_debugfs_open,
 761                         .write = ide_core_cp_entry} },
 762 };
 763
 764 static struct dentry *lkdtm_debugfs_root;
 765
 766 static int __init lkdtm_module_init(void)
 767 {
 768         int ret = -EINVAL;
 769         int n_debugfs_entries = 1; /* Assume only the direct entry */
 770         int i;
 771
 772         /* Register debugfs interface */
 773         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 774         if (!lkdtm_debugfs_root) {
 775                 printk(KERN_ERR "lkdtm: creating root dir failed\n");
 776                 return -ENODEV;
 777         }
 778
 779 #ifdef CONFIG_KPROBES
 780         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 781 #endif
 782
 783         for (i = 0; i < n_debugfs_entries; i++) {
 784                 const struct crash_entry *cur = &crash_entries[i];
 785                 struct dentry *de;
 786
 787                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 788                                 NULL, &cur->fops);
 789                 if (de == NULL) {
 790                         printk(KERN_ERR "lkdtm: could not create %s\n",
 791                                         cur->name);
 792                         goto out_err;
 793                 }
 794         }
 795
 796         if (lkdtm_parse_commandline() == -EINVAL) {
 797                 printk(KERN_INFO "lkdtm: Invalid command\n");
 798                 goto out_err;
 799         }
 800
 801         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 802                 ret = lkdtm_register_cpoint(cpoint);
 803                 if (ret < 0) {
 804                         printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
 805                                         cpoint);
 806                         goto out_err;
 807                 }
 808                 printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
 809                                 cpoint_name, cpoint_type);
 810         } else {
 811                 printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
 812         }
 813
 814         return 0;
 815
 816 out_err:
 817         debugfs_remove_recursive(lkdtm_debugfs_root);
 818         return ret;
 819 }
 820
 821 static void __exit lkdtm_module_exit(void)
 822 {
 823         debugfs_remove_recursive(lkdtm_debugfs_root);
 824
 825         unregister_jprobe(&lkdtm);
 826         printk(KERN_INFO "lkdtm: Crash point unregistered\n");
 827 }
 828
 829 module_init(lkdtm_module_init);
 830 module_exit(lkdtm_module_exit);
 831
 832 MODULE_LICENSE("GPL");