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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  34
  35 #include <linux/kernel.h>
  36 #include <linux/fs.h>
  37 #include <linux/module.h>
  38 #include <linux/buffer_head.h>
  39 #include <linux/kprobes.h>
  40 #include <linux/list.h>
  41 #include <linux/init.h>
  42 #include <linux/interrupt.h>
  43 #include <linux/hrtimer.h>
  44 #include <linux/slab.h>
  45 #include <scsi/scsi_cmnd.h>
  46 #include <linux/debugfs.h>
  47 #include <linux/vmalloc.h>
  48 #include <linux/mman.h>
  49
  50 #ifdef CONFIG_IDE
  51 #include <linux/ide.h>
  52 #endif
  53
  54 /*
  55  * Make sure our attempts to over run the kernel stack doesn't trigger
  56  * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
  57  * recurse past the end of THREAD_SIZE by default.
  58  */
  59 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
  60 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
  61 #else
  62 #define REC_STACK_SIZE (THREAD_SIZE / 8)
  63 #endif
  64 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
  65
  66 #define DEFAULT_COUNT 10
  67 #define EXEC_SIZE 64
  68
  69 enum cname {
  70         CN_INVALID,
  71         CN_INT_HARDWARE_ENTRY,
  72         CN_INT_HW_IRQ_EN,
  73         CN_INT_TASKLET_ENTRY,
  74         CN_FS_DEVRW,
  75         CN_MEM_SWAPOUT,
  76         CN_TIMERADD,
  77         CN_SCSI_DISPATCH_CMD,
  78         CN_IDE_CORE_CP,
  79         CN_DIRECT,
  80 };
  81
  82 enum ctype {
  83         CT_NONE,
  84         CT_PANIC,
  85         CT_BUG,
  86         CT_WARNING,
  87         CT_EXCEPTION,
  88         CT_LOOP,
  89         CT_OVERFLOW,
  90         CT_CORRUPT_STACK,
  91         CT_UNALIGNED_LOAD_STORE_WRITE,
  92         CT_OVERWRITE_ALLOCATION,
  93         CT_WRITE_AFTER_FREE,
  94         CT_SOFTLOCKUP,
  95         CT_HARDLOCKUP,
  96         CT_SPINLOCKUP,
  97         CT_HUNG_TASK,
  98         CT_EXEC_DATA,
  99         CT_EXEC_STACK,
 100         CT_EXEC_KMALLOC,
 101         CT_EXEC_VMALLOC,
 102         CT_EXEC_USERSPACE,
 103         CT_ACCESS_USERSPACE,
 104         CT_WRITE_RO,
 105 };
 106
 107 static char* cp_name[] = {
 108         "INT_HARDWARE_ENTRY",
 109         "INT_HW_IRQ_EN",
 110         "INT_TASKLET_ENTRY",
 111         "FS_DEVRW",
 112         "MEM_SWAPOUT",
 113         "TIMERADD",
 114         "SCSI_DISPATCH_CMD",
 115         "IDE_CORE_CP",
 116         "DIRECT",
 117 };
 118
 119 static char* cp_type[] = {
 120         "PANIC",
 121         "BUG",
 122         "WARNING",
 123         "EXCEPTION",
 124         "LOOP",
 125         "OVERFLOW",
 126         "CORRUPT_STACK",
 127         "UNALIGNED_LOAD_STORE_WRITE",
 128         "OVERWRITE_ALLOCATION",
 129         "WRITE_AFTER_FREE",
 130         "SOFTLOCKUP",
 131         "HARDLOCKUP",
 132         "SPINLOCKUP",
 133         "HUNG_TASK",
 134         "EXEC_DATA",
 135         "EXEC_STACK",
 136         "EXEC_KMALLOC",
 137         "EXEC_VMALLOC",
 138         "EXEC_USERSPACE",
 139         "ACCESS_USERSPACE",
 140         "WRITE_RO",
 141 };
 142
 143 static struct jprobe lkdtm;
 144
 145 static int lkdtm_parse_commandline(void);
 146 static void lkdtm_handler(void);
 147
 148 static char* cpoint_name;
 149 static char* cpoint_type;
 150 static int cpoint_count = DEFAULT_COUNT;
 151 static int recur_count = REC_NUM_DEFAULT;
 152
 153 static enum cname cpoint = CN_INVALID;
 154 static enum ctype cptype = CT_NONE;
 155 static int count = DEFAULT_COUNT;
 156 static DEFINE_SPINLOCK(count_lock);
 157 static DEFINE_SPINLOCK(lock_me_up);
 158
 159 static u8 data_area[EXEC_SIZE];
 160
 161 static const unsigned long rodata = 0xAA55AA55;
 162
 163 module_param(recur_count, int, 0644);
 164 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 165 module_param(cpoint_name, charp, 0444);
 166 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 167 module_param(cpoint_type, charp, 0444);
 168 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 169                                 "hitting the crash point");
 170 module_param(cpoint_count, int, 0644);
 171 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 172                                 "crash point is to be hit to trigger action");
 173
 174 static unsigned int jp_do_irq(unsigned int irq)
 175 {
 176         lkdtm_handler();
 177         jprobe_return();
 178         return 0;
 179 }
 180
 181 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 182                                        struct irqaction *action)
 183 {
 184         lkdtm_handler();
 185         jprobe_return();
 186         return 0;
 187 }
 188
 189 static void jp_tasklet_action(struct softirq_action *a)
 190 {
 191         lkdtm_handler();
 192         jprobe_return();
 193 }
 194
 195 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 196 {
 197         lkdtm_handler();
 198         jprobe_return();
 199 }
 200
 201 struct scan_control;
 202
 203 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 204                                              struct zone *zone,
 205                                              struct scan_control *sc)
 206 {
 207         lkdtm_handler();
 208         jprobe_return();
 209         return 0;
 210 }
 211
 212 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 213                             const enum hrtimer_mode mode)
 214 {
 215         lkdtm_handler();
 216         jprobe_return();
 217         return 0;
 218 }
 219
 220 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 221 {
 222         lkdtm_handler();
 223         jprobe_return();
 224         return 0;
 225 }
 226
 227 #ifdef CONFIG_IDE
 228 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 229                         struct block_device *bdev, unsigned int cmd,
 230                         unsigned long arg)
 231 {
 232         lkdtm_handler();
 233         jprobe_return();
 234         return 0;
 235 }
 236 #endif
 237
 238 /* Return the crashpoint number or NONE if the name is invalid */
 239 static enum ctype parse_cp_type(const char *what, size_t count)
 240 {
 241         int i;
 242
 243         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 244                 if (!strcmp(what, cp_type[i]))
 245                         return i + 1;
 246         }
 247
 248         return CT_NONE;
 249 }
 250
 251 static const char *cp_type_to_str(enum ctype type)
 252 {
 253         if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 254                 return "None";
 255
 256         return cp_type[type - 1];
 257 }
 258
 259 static const char *cp_name_to_str(enum cname name)
 260 {
 261         if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 262                 return "INVALID";
 263
 264         return cp_name[name - 1];
 265 }
 266
 267
 268 static int lkdtm_parse_commandline(void)
 269 {
 270         int i;
 271         unsigned long flags;
 272
 273         if (cpoint_count < 1 || recur_count < 1)
 274                 return -EINVAL;
 275
 276         spin_lock_irqsave(&count_lock, flags);
 277         count = cpoint_count;
 278         spin_unlock_irqrestore(&count_lock, flags);
 279
 280         /* No special parameters */
 281         if (!cpoint_type && !cpoint_name)
 282                 return 0;
 283
 284         /* Neither or both of these need to be set */
 285         if (!cpoint_type || !cpoint_name)
 286                 return -EINVAL;
 287
 288         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 289         if (cptype == CT_NONE)
 290                 return -EINVAL;
 291
 292         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 293                 if (!strcmp(cpoint_name, cp_name[i])) {
 294                         cpoint = i + 1;
 295                         return 0;
 296                 }
 297         }
 298
 299         /* Could not find a valid crash point */
 300         return -EINVAL;
 301 }
 302
 303 static int recursive_loop(int remaining)
 304 {
 305         char buf[REC_STACK_SIZE];
 306
 307         /* Make sure compiler does not optimize this away. */
 308         memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
 309         if (!remaining)
 310                 return 0;
 311         else
 312                 return recursive_loop(remaining - 1);
 313 }
 314
 315 static void do_nothing(void)
 316 {
 317         return;
 318 }
 319
 320 static noinline void corrupt_stack(void)
 321 {
 322         /* Use default char array length that triggers stack protection. */
 323         char data[8];
 324
 325         memset((void *)data, 0, 64);
 326 }
 327
 328 static void execute_location(void *dst)
 329 {
 330         void (*func)(void) = dst;
 331
 332         pr_info("attempting ok execution at %p\n", do_nothing);
 333         do_nothing();
 334
 335         memcpy(dst, do_nothing, EXEC_SIZE);
 336         flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
 337         pr_info("attempting bad execution at %p\n", func);
 338         func();
 339 }
 340
 341 static void execute_user_location(void *dst)
 342 {
 343         /* Intentionally crossing kernel/user memory boundary. */
 344         void (*func)(void) = dst;
 345
 346         pr_info("attempting ok execution at %p\n", do_nothing);
 347         do_nothing();
 348
 349         if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
 350                 return;
 351         flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
 352         pr_info("attempting bad execution at %p\n", func);
 353         func();
 354 }
 355
 356 static void lkdtm_do_action(enum ctype which)
 357 {
 358         switch (which) {
 359         case CT_PANIC:
 360                 panic("dumptest");
 361                 break;
 362         case CT_BUG:
 363                 BUG();
 364                 break;
 365         case CT_WARNING:
 366                 WARN_ON(1);
 367                 break;
 368         case CT_EXCEPTION:
 369                 *((int *) 0) = 0;
 370                 break;
 371         case CT_LOOP:
 372                 for (;;)
 373                         ;
 374                 break;
 375         case CT_OVERFLOW:
 376                 (void) recursive_loop(recur_count);
 377                 break;
 378         case CT_CORRUPT_STACK:
 379                 corrupt_stack();
 380                 break;
 381         case CT_UNALIGNED_LOAD_STORE_WRITE: {
 382                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 383                                 3, 4, 5};
 384                 u32 *p;
 385                 u32 val = 0x12345678;
 386
 387                 p = (u32 *)(data + 1);
 388                 if (*p == 0)
 389                         val = 0x87654321;
 390                 *p = val;
 391                  break;
 392         }
 393         case CT_OVERWRITE_ALLOCATION: {
 394                 size_t len = 1020;
 395                 u32 *data = kmalloc(len, GFP_KERNEL);
 396
 397                 data[1024 / sizeof(u32)] = 0x12345678;
 398                 kfree(data);
 399                 break;
 400         }
 401         case CT_WRITE_AFTER_FREE: {
 402                 size_t len = 1024;
 403                 u32 *data = kmalloc(len, GFP_KERNEL);
 404
 405                 kfree(data);
 406                 schedule();
 407                 memset(data, 0x78, len);
 408                 break;
 409         }
 410         case CT_SOFTLOCKUP:
 411                 preempt_disable();
 412                 for (;;)
 413                         cpu_relax();
 414                 break;
 415         case CT_HARDLOCKUP:
 416                 local_irq_disable();
 417                 for (;;)
 418                         cpu_relax();
 419                 break;
 420         case CT_SPINLOCKUP:
 421                 /* Must be called twice to trigger. */
 422                 spin_lock(&lock_me_up);
 423                 /* Let sparse know we intended to exit holding the lock. */
 424                 __release(&lock_me_up);
 425                 break;
 426         case CT_HUNG_TASK:
 427                 set_current_state(TASK_UNINTERRUPTIBLE);
 428                 schedule();
 429                 break;
 430         case CT_EXEC_DATA:
 431                 execute_location(data_area);
 432                 break;
 433         case CT_EXEC_STACK: {
 434                 u8 stack_area[EXEC_SIZE];
 435                 execute_location(stack_area);
 436                 break;
 437         }
 438         case CT_EXEC_KMALLOC: {
 439                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 440                 execute_location(kmalloc_area);
 441                 kfree(kmalloc_area);
 442                 break;
 443         }
 444         case CT_EXEC_VMALLOC: {
 445                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 446                 execute_location(vmalloc_area);
 447                 vfree(vmalloc_area);
 448                 break;
 449         }
 450         case CT_EXEC_USERSPACE: {
 451                 unsigned long user_addr;
 452
 453                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 454                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 455                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 456                 if (user_addr >= TASK_SIZE) {
 457                         pr_warn("Failed to allocate user memory\n");
 458                         return;
 459                 }
 460                 execute_user_location((void *)user_addr);
 461                 vm_munmap(user_addr, PAGE_SIZE);
 462                 break;
 463         }
 464         case CT_ACCESS_USERSPACE: {
 465                 unsigned long user_addr, tmp;
 466                 unsigned long *ptr;
 467
 468                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 469                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 470                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 471                 if (user_addr >= TASK_SIZE) {
 472                         pr_warn("Failed to allocate user memory\n");
 473                         return;
 474                 }
 475
 476                 ptr = (unsigned long *)user_addr;
 477
 478                 pr_info("attempting bad read at %p\n", ptr);
 479                 tmp = *ptr;
 480                 tmp += 0xc0dec0de;
 481
 482                 pr_info("attempting bad write at %p\n", ptr);
 483                 *ptr = tmp;
 484
 485                 vm_munmap(user_addr, PAGE_SIZE);
 486
 487                 break;
 488         }
 489         case CT_WRITE_RO: {
 490                 unsigned long *ptr;
 491
 492                 ptr = (unsigned long *)&rodata;
 493
 494                 pr_info("attempting bad write at %p\n", ptr);
 495                 *ptr ^= 0xabcd1234;
 496
 497                 break;
 498         }
 499         case CT_NONE:
 500         default:
 501                 break;
 502         }
 503
 504 }
 505
 506 static void lkdtm_handler(void)
 507 {
 508         unsigned long flags;
 509         bool do_it = false;
 510
 511         spin_lock_irqsave(&count_lock, flags);
 512         count--;
 513         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 514                 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 515
 516         if (count == 0) {
 517                 do_it = true;
 518                 count = cpoint_count;
 519         }
 520         spin_unlock_irqrestore(&count_lock, flags);
 521
 522         if (do_it)
 523                 lkdtm_do_action(cptype);
 524 }
 525
 526 static int lkdtm_register_cpoint(enum cname which)
 527 {
 528         int ret;
 529
 530         cpoint = CN_INVALID;
 531         if (lkdtm.entry != NULL)
 532                 unregister_jprobe(&lkdtm);
 533
 534         switch (which) {
 535         case CN_DIRECT:
 536                 lkdtm_do_action(cptype);
 537                 return 0;
 538         case CN_INT_HARDWARE_ENTRY:
 539                 lkdtm.kp.symbol_name = "do_IRQ";
 540                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 541                 break;
 542         case CN_INT_HW_IRQ_EN:
 543                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 544                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 545                 break;
 546         case CN_INT_TASKLET_ENTRY:
 547                 lkdtm.kp.symbol_name = "tasklet_action";
 548                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 549                 break;
 550         case CN_FS_DEVRW:
 551                 lkdtm.kp.symbol_name = "ll_rw_block";
 552                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 553                 break;
 554         case CN_MEM_SWAPOUT:
 555                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 556                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 557                 break;
 558         case CN_TIMERADD:
 559                 lkdtm.kp.symbol_name = "hrtimer_start";
 560                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 561                 break;
 562         case CN_SCSI_DISPATCH_CMD:
 563                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 564                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 565                 break;
 566         case CN_IDE_CORE_CP:
 567 #ifdef CONFIG_IDE
 568                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 569                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 570 #else
 571                 pr_info("Crash point not available\n");
 572                 return -EINVAL;
 573 #endif
 574                 break;
 575         default:
 576                 pr_info("Invalid Crash Point\n");
 577                 return -EINVAL;
 578         }
 579
 580         cpoint = which;
 581         if ((ret = register_jprobe(&lkdtm)) < 0) {
 582                 pr_info("Couldn't register jprobe\n");
 583                 cpoint = CN_INVALID;
 584         }
 585
 586         return ret;
 587 }
 588
 589 static ssize_t do_register_entry(enum cname which, struct file *f,
 590                 const char __user *user_buf, size_t count, loff_t *off)
 591 {
 592         char *buf;
 593         int err;
 594
 595         if (count >= PAGE_SIZE)
 596                 return -EINVAL;
 597
 598         buf = (char *)__get_free_page(GFP_KERNEL);
 599         if (!buf)
 600                 return -ENOMEM;
 601         if (copy_from_user(buf, user_buf, count)) {
 602                 free_page((unsigned long) buf);
 603                 return -EFAULT;
 604         }
 605         /* NULL-terminate and remove enter */
 606         buf[count] = '\0';
 607         strim(buf);
 608
 609         cptype = parse_cp_type(buf, count);
 610         free_page((unsigned long) buf);
 611
 612         if (cptype == CT_NONE)
 613                 return -EINVAL;
 614
 615         err = lkdtm_register_cpoint(which);
 616         if (err < 0)
 617                 return err;
 618
 619         *off += count;
 620
 621         return count;
 622 }
 623
 624 /* Generic read callback that just prints out the available crash types */
 625 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 626                 size_t count, loff_t *off)
 627 {
 628         char *buf;
 629         int i, n, out;
 630
 631         buf = (char *)__get_free_page(GFP_KERNEL);
 632         if (buf == NULL)
 633                 return -ENOMEM;
 634
 635         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 636         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 637                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 638         buf[n] = '\0';
 639
 640         out = simple_read_from_buffer(user_buf, count, off,
 641                                       buf, n);
 642         free_page((unsigned long) buf);
 643
 644         return out;
 645 }
 646
 647 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 648 {
 649         return 0;
 650 }
 651
 652
 653 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 654                 size_t count, loff_t *off)
 655 {
 656         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 657 }
 658
 659 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 660                 size_t count, loff_t *off)
 661 {
 662         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 663 }
 664
 665 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 666                 size_t count, loff_t *off)
 667 {
 668         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 669 }
 670
 671 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 672                 size_t count, loff_t *off)
 673 {
 674         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 675 }
 676
 677 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 678                 size_t count, loff_t *off)
 679 {
 680         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 681 }
 682
 683 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 684                 size_t count, loff_t *off)
 685 {
 686         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 687 }
 688
 689 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 690                 const char __user *buf, size_t count, loff_t *off)
 691 {
 692         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 693 }
 694
 695 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 696                 size_t count, loff_t *off)
 697 {
 698         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 699 }
 700
 701 /* Special entry to just crash directly. Available without KPROBEs */
 702 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 703                 size_t count, loff_t *off)
 704 {
 705         enum ctype type;
 706         char *buf;
 707
 708         if (count >= PAGE_SIZE)
 709                 return -EINVAL;
 710         if (count < 1)
 711                 return -EINVAL;
 712
 713         buf = (char *)__get_free_page(GFP_KERNEL);
 714         if (!buf)
 715                 return -ENOMEM;
 716         if (copy_from_user(buf, user_buf, count)) {
 717                 free_page((unsigned long) buf);
 718                 return -EFAULT;
 719         }
 720         /* NULL-terminate and remove enter */
 721         buf[count] = '\0';
 722         strim(buf);
 723
 724         type = parse_cp_type(buf, count);
 725         free_page((unsigned long) buf);
 726         if (type == CT_NONE)
 727                 return -EINVAL;
 728
 729         pr_info("Performing direct entry %s\n", cp_type_to_str(type));
 730         lkdtm_do_action(type);
 731         *off += count;
 732
 733         return count;
 734 }
 735
 736 struct crash_entry {
 737         const char *name;
 738         const struct file_operations fops;
 739 };
 740
 741 static const struct crash_entry crash_entries[] = {
 742         {"DIRECT", {.read = lkdtm_debugfs_read,
 743                         .llseek = generic_file_llseek,
 744                         .open = lkdtm_debugfs_open,
 745                         .write = direct_entry} },
 746         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 747                         .llseek = generic_file_llseek,
 748                         .open = lkdtm_debugfs_open,
 749                         .write = int_hardware_entry} },
 750         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 751                         .llseek = generic_file_llseek,
 752                         .open = lkdtm_debugfs_open,
 753                         .write = int_hw_irq_en} },
 754         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 755                         .llseek = generic_file_llseek,
 756                         .open = lkdtm_debugfs_open,
 757                         .write = int_tasklet_entry} },
 758         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 759                         .llseek = generic_file_llseek,
 760                         .open = lkdtm_debugfs_open,
 761                         .write = fs_devrw_entry} },
 762         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 763                         .llseek = generic_file_llseek,
 764                         .open = lkdtm_debugfs_open,
 765                         .write = mem_swapout_entry} },
 766         {"TIMERADD", {.read = lkdtm_debugfs_read,
 767                         .llseek = generic_file_llseek,
 768                         .open = lkdtm_debugfs_open,
 769                         .write = timeradd_entry} },
 770         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 771                         .llseek = generic_file_llseek,
 772                         .open = lkdtm_debugfs_open,
 773                         .write = scsi_dispatch_cmd_entry} },
 774         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 775                         .llseek = generic_file_llseek,
 776                         .open = lkdtm_debugfs_open,
 777                         .write = ide_core_cp_entry} },
 778 };
 779
 780 static struct dentry *lkdtm_debugfs_root;
 781
 782 static int __init lkdtm_module_init(void)
 783 {
 784         int ret = -EINVAL;
 785         int n_debugfs_entries = 1; /* Assume only the direct entry */
 786         int i;
 787
 788         /* Register debugfs interface */
 789         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 790         if (!lkdtm_debugfs_root) {
 791                 pr_err("creating root dir failed\n");
 792                 return -ENODEV;
 793         }
 794
 795 #ifdef CONFIG_KPROBES
 796         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 797 #endif
 798
 799         for (i = 0; i < n_debugfs_entries; i++) {
 800                 const struct crash_entry *cur = &crash_entries[i];
 801                 struct dentry *de;
 802
 803                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 804                                 NULL, &cur->fops);
 805                 if (de == NULL) {
 806                         pr_err("could not create %s\n", cur->name);
 807                         goto out_err;
 808                 }
 809         }
 810
 811         if (lkdtm_parse_commandline() == -EINVAL) {
 812                 pr_info("Invalid command\n");
 813                 goto out_err;
 814         }
 815
 816         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 817                 ret = lkdtm_register_cpoint(cpoint);
 818                 if (ret < 0) {
 819                         pr_info("Invalid crash point %d\n", cpoint);
 820                         goto out_err;
 821                 }
 822                 pr_info("Crash point %s of type %s registered\n",
 823                         cpoint_name, cpoint_type);
 824         } else {
 825                 pr_info("No crash points registered, enable through debugfs\n");
 826         }
 827
 828         return 0;
 829
 830 out_err:
 831         debugfs_remove_recursive(lkdtm_debugfs_root);
 832         return ret;
 833 }
 834
 835 static void __exit lkdtm_module_exit(void)
 836 {
 837         debugfs_remove_recursive(lkdtm_debugfs_root);
 838
 839         unregister_jprobe(&lkdtm);
 840         pr_info("Crash point unregistered\n");
 841 }
 842
 843 module_init(lkdtm_module_init);
 844 module_exit(lkdtm_module_exit);
 845
 846 MODULE_LICENSE("GPL");