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 #include <asm/cacheflush.h>
  50
  51 #ifdef CONFIG_IDE
  52 #include <linux/ide.h>
  53 #endif
  54
  55 /*
  56  * Make sure our attempts to over run the kernel stack doesn't trigger
  57  * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
  58  * recurse past the end of THREAD_SIZE by default.
  59  */
  60 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
  61 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
  62 #else
  63 #define REC_STACK_SIZE (THREAD_SIZE / 8)
  64 #endif
  65 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
  66
  67 #define DEFAULT_COUNT 10
  68 #define EXEC_SIZE 64
  69
  70 enum cname {
  71         CN_INVALID,
  72         CN_INT_HARDWARE_ENTRY,
  73         CN_INT_HW_IRQ_EN,
  74         CN_INT_TASKLET_ENTRY,
  75         CN_FS_DEVRW,
  76         CN_MEM_SWAPOUT,
  77         CN_TIMERADD,
  78         CN_SCSI_DISPATCH_CMD,
  79         CN_IDE_CORE_CP,
  80         CN_DIRECT,
  81 };
  82
  83 enum ctype {
  84         CT_NONE,
  85         CT_PANIC,
  86         CT_BUG,
  87         CT_WARNING,
  88         CT_EXCEPTION,
  89         CT_LOOP,
  90         CT_OVERFLOW,
  91         CT_CORRUPT_STACK,
  92         CT_UNALIGNED_LOAD_STORE_WRITE,
  93         CT_OVERWRITE_ALLOCATION,
  94         CT_WRITE_AFTER_FREE,
  95         CT_READ_AFTER_FREE,
  96         CT_WRITE_BUDDY_AFTER_FREE,
  97         CT_READ_BUDDY_AFTER_FREE,
  98         CT_SOFTLOCKUP,
  99         CT_HARDLOCKUP,
 100         CT_SPINLOCKUP,
 101         CT_HUNG_TASK,
 102         CT_EXEC_DATA,
 103         CT_EXEC_STACK,
 104         CT_EXEC_KMALLOC,
 105         CT_EXEC_VMALLOC,
 106         CT_EXEC_USERSPACE,
 107         CT_ACCESS_USERSPACE,
 108         CT_WRITE_RO,
 109         CT_WRITE_KERN,
 110         CT_WRAP_ATOMIC
 111 };
 112
 113 static char* cp_name[] = {
 114         "INT_HARDWARE_ENTRY",
 115         "INT_HW_IRQ_EN",
 116         "INT_TASKLET_ENTRY",
 117         "FS_DEVRW",
 118         "MEM_SWAPOUT",
 119         "TIMERADD",
 120         "SCSI_DISPATCH_CMD",
 121         "IDE_CORE_CP",
 122         "DIRECT",
 123 };
 124
 125 static char* cp_type[] = {
 126         "PANIC",
 127         "BUG",
 128         "WARNING",
 129         "EXCEPTION",
 130         "LOOP",
 131         "OVERFLOW",
 132         "CORRUPT_STACK",
 133         "UNALIGNED_LOAD_STORE_WRITE",
 134         "OVERWRITE_ALLOCATION",
 135         "WRITE_AFTER_FREE",
 136         "READ_AFTER_FREE",
 137         "WRITE_BUDDY_AFTER_FREE",
 138         "READ_BUDDY_AFTER_FREE",
 139         "SOFTLOCKUP",
 140         "HARDLOCKUP",
 141         "SPINLOCKUP",
 142         "HUNG_TASK",
 143         "EXEC_DATA",
 144         "EXEC_STACK",
 145         "EXEC_KMALLOC",
 146         "EXEC_VMALLOC",
 147         "EXEC_USERSPACE",
 148         "ACCESS_USERSPACE",
 149         "WRITE_RO",
 150         "WRITE_KERN",
 151         "WRAP_ATOMIC"
 152 };
 153
 154 static struct jprobe lkdtm;
 155
 156 static int lkdtm_parse_commandline(void);
 157 static void lkdtm_handler(void);
 158
 159 static char* cpoint_name;
 160 static char* cpoint_type;
 161 static int cpoint_count = DEFAULT_COUNT;
 162 static int recur_count = REC_NUM_DEFAULT;
 163
 164 static enum cname cpoint = CN_INVALID;
 165 static enum ctype cptype = CT_NONE;
 166 static int count = DEFAULT_COUNT;
 167 static DEFINE_SPINLOCK(count_lock);
 168 static DEFINE_SPINLOCK(lock_me_up);
 169
 170 static u8 data_area[EXEC_SIZE];
 171
 172 static const unsigned long rodata = 0xAA55AA55;
 173
 174 module_param(recur_count, int, 0644);
 175 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 176 module_param(cpoint_name, charp, 0444);
 177 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 178 module_param(cpoint_type, charp, 0444);
 179 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 180                                 "hitting the crash point");
 181 module_param(cpoint_count, int, 0644);
 182 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 183                                 "crash point is to be hit to trigger action");
 184
 185 static unsigned int jp_do_irq(unsigned int irq)
 186 {
 187         lkdtm_handler();
 188         jprobe_return();
 189         return 0;
 190 }
 191
 192 static irqreturn_t jp_handle_irq_event(unsigned int irq,
 193                                        struct irqaction *action)
 194 {
 195         lkdtm_handler();
 196         jprobe_return();
 197         return 0;
 198 }
 199
 200 static void jp_tasklet_action(struct softirq_action *a)
 201 {
 202         lkdtm_handler();
 203         jprobe_return();
 204 }
 205
 206 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 207 {
 208         lkdtm_handler();
 209         jprobe_return();
 210 }
 211
 212 struct scan_control;
 213
 214 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 215                                              struct zone *zone,
 216                                              struct scan_control *sc)
 217 {
 218         lkdtm_handler();
 219         jprobe_return();
 220         return 0;
 221 }
 222
 223 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 224                             const enum hrtimer_mode mode)
 225 {
 226         lkdtm_handler();
 227         jprobe_return();
 228         return 0;
 229 }
 230
 231 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 232 {
 233         lkdtm_handler();
 234         jprobe_return();
 235         return 0;
 236 }
 237
 238 #ifdef CONFIG_IDE
 239 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 240                         struct block_device *bdev, unsigned int cmd,
 241                         unsigned long arg)
 242 {
 243         lkdtm_handler();
 244         jprobe_return();
 245         return 0;
 246 }
 247 #endif
 248
 249 /* Return the crashpoint number or NONE if the name is invalid */
 250 static enum ctype parse_cp_type(const char *what, size_t count)
 251 {
 252         int i;
 253
 254         for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
 255                 if (!strcmp(what, cp_type[i]))
 256                         return i + 1;
 257         }
 258
 259         return CT_NONE;
 260 }
 261
 262 static const char *cp_type_to_str(enum ctype type)
 263 {
 264         if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
 265                 return "None";
 266
 267         return cp_type[type - 1];
 268 }
 269
 270 static const char *cp_name_to_str(enum cname name)
 271 {
 272         if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
 273                 return "INVALID";
 274
 275         return cp_name[name - 1];
 276 }
 277
 278
 279 static int lkdtm_parse_commandline(void)
 280 {
 281         int i;
 282         unsigned long flags;
 283
 284         if (cpoint_count < 1 || recur_count < 1)
 285                 return -EINVAL;
 286
 287         spin_lock_irqsave(&count_lock, flags);
 288         count = cpoint_count;
 289         spin_unlock_irqrestore(&count_lock, flags);
 290
 291         /* No special parameters */
 292         if (!cpoint_type && !cpoint_name)
 293                 return 0;
 294
 295         /* Neither or both of these need to be set */
 296         if (!cpoint_type || !cpoint_name)
 297                 return -EINVAL;
 298
 299         cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
 300         if (cptype == CT_NONE)
 301                 return -EINVAL;
 302
 303         for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
 304                 if (!strcmp(cpoint_name, cp_name[i])) {
 305                         cpoint = i + 1;
 306                         return 0;
 307                 }
 308         }
 309
 310         /* Could not find a valid crash point */
 311         return -EINVAL;
 312 }
 313
 314 static int recursive_loop(int remaining)
 315 {
 316         char buf[REC_STACK_SIZE];
 317
 318         /* Make sure compiler does not optimize this away. */
 319         memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
 320         if (!remaining)
 321                 return 0;
 322         else
 323                 return recursive_loop(remaining - 1);
 324 }
 325
 326 static void do_nothing(void)
 327 {
 328         return;
 329 }
 330
 331 /* Must immediately follow do_nothing for size calculuations to work out. */
 332 static void do_overwritten(void)
 333 {
 334         pr_info("do_overwritten wasn't overwritten!\n");
 335         return;
 336 }
 337
 338 static noinline void corrupt_stack(void)
 339 {
 340         /* Use default char array length that triggers stack protection. */
 341         char data[8];
 342
 343         memset((void *)data, 0, 64);
 344 }
 345
 346 static void execute_location(void *dst)
 347 {
 348         void (*func)(void) = dst;
 349
 350         pr_info("attempting ok execution at %p\n", do_nothing);
 351         do_nothing();
 352
 353         memcpy(dst, do_nothing, EXEC_SIZE);
 354         flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
 355         pr_info("attempting bad execution at %p\n", func);
 356         func();
 357 }
 358
 359 static void execute_user_location(void *dst)
 360 {
 361         /* Intentionally crossing kernel/user memory boundary. */
 362         void (*func)(void) = dst;
 363
 364         pr_info("attempting ok execution at %p\n", do_nothing);
 365         do_nothing();
 366
 367         if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
 368                 return;
 369         flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
 370         pr_info("attempting bad execution at %p\n", func);
 371         func();
 372 }
 373
 374 static void lkdtm_do_action(enum ctype which)
 375 {
 376         switch (which) {
 377         case CT_PANIC:
 378                 panic("dumptest");
 379                 break;
 380         case CT_BUG:
 381                 BUG();
 382                 break;
 383         case CT_WARNING:
 384                 WARN_ON(1);
 385                 break;
 386         case CT_EXCEPTION:
 387                 *((int *) 0) = 0;
 388                 break;
 389         case CT_LOOP:
 390                 for (;;)
 391                         ;
 392                 break;
 393         case CT_OVERFLOW:
 394                 (void) recursive_loop(recur_count);
 395                 break;
 396         case CT_CORRUPT_STACK:
 397                 corrupt_stack();
 398                 break;
 399         case CT_UNALIGNED_LOAD_STORE_WRITE: {
 400                 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
 401                                 3, 4, 5};
 402                 u32 *p;
 403                 u32 val = 0x12345678;
 404
 405                 p = (u32 *)(data + 1);
 406                 if (*p == 0)
 407                         val = 0x87654321;
 408                 *p = val;
 409                  break;
 410         }
 411         case CT_OVERWRITE_ALLOCATION: {
 412                 size_t len = 1020;
 413                 u32 *data = kmalloc(len, GFP_KERNEL);
 414
 415                 data[1024 / sizeof(u32)] = 0x12345678;
 416                 kfree(data);
 417                 break;
 418         }
 419         case CT_WRITE_AFTER_FREE: {
 420                 int *base;
 421                 size_t len = 1024;
 422                 /*
 423                  * The slub allocator uses the first word to store the free
 424                  * pointer in some configurations. Use the middle of the
 425                  * allocation to avoid running into the freelist
 426                  */
 427                 size_t offset = (len / sizeof(*base)) / 2;
 428
 429                 base = kmalloc(len, GFP_KERNEL);
 430                 pr_info("Allocated memory %p-%p\n", base, &base[offset * 2]);
 431                 kfree(base);
 432                 pr_info("Attempting bad write to freed memory at %p\n",
 433                         &base[offset]);
 434                 base[offset] = 0x0abcdef0;
 435                 break;
 436         }
 437         case CT_READ_AFTER_FREE: {
 438                 int *base, *val, saw;
 439                 size_t len = 1024;
 440                 /*
 441                  * The slub allocator uses the first word to store the free
 442                  * pointer in some configurations. Use the middle of the
 443                  * allocation to avoid running into the freelist
 444                  */
 445                 size_t offset = (len / sizeof(*base)) / 2;
 446
 447                 base = kmalloc(len, GFP_KERNEL);
 448                 if (!base)
 449                         break;
 450
 451                 val = kmalloc(len, GFP_KERNEL);
 452                 if (!val)
 453                         break;
 454
 455                 *val = 0x12345678;
 456                 base[offset] = *val;
 457                 pr_info("Value in memory before free: %x\n", base[offset]);
 458
 459                 kfree(base);
 460
 461                 pr_info("Attempting bad read from freed memory\n");
 462                 saw = base[offset];
 463                 if (saw != *val) {
 464                         /* Good! Poisoning happened, so declare a win. */
 465                         pr_info("Memory correctly poisoned, calling BUG\n");
 466                         BUG();
 467                 }
 468                 pr_info("Memory was not poisoned\n");
 469
 470                 kfree(val);
 471                 break;
 472         }
 473         case CT_WRITE_BUDDY_AFTER_FREE: {
 474                 unsigned long p = __get_free_page(GFP_KERNEL);
 475                 if (!p)
 476                         break;
 477                 pr_info("Writing to the buddy page before free\n");
 478                 memset((void *)p, 0x3, PAGE_SIZE);
 479                 free_page(p);
 480                 schedule();
 481                 pr_info("Attempting bad write to the buddy page after free\n");
 482                 memset((void *)p, 0x78, PAGE_SIZE);
 483                 break;
 484         }
 485         case CT_READ_BUDDY_AFTER_FREE: {
 486                 unsigned long p = __get_free_page(GFP_KERNEL);
 487                 int saw, *val = kmalloc(1024, GFP_KERNEL);
 488                 int *base;
 489
 490                 if (!p)
 491                         break;
 492
 493                 if (!val)
 494                         break;
 495
 496                 base = (int *)p;
 497
 498                 *val = 0x12345678;
 499                 base[0] = *val;
 500                 pr_info("Value in memory before free: %x\n", base[0]);
 501                 free_page(p);
 502                 pr_info("Attempting to read from freed memory\n");
 503                 saw = base[0];
 504                 if (saw != *val) {
 505                         /* Good! Poisoning happened, so declare a win. */
 506                         pr_info("Buddy page correctly poisoned, calling BUG\n");
 507                         BUG();
 508                 }
 509                 pr_info("Buddy page was not poisoned\n");
 510
 511                 kfree(val);
 512                 break;
 513         }
 514         case CT_SOFTLOCKUP:
 515                 preempt_disable();
 516                 for (;;)
 517                         cpu_relax();
 518                 break;
 519         case CT_HARDLOCKUP:
 520                 local_irq_disable();
 521                 for (;;)
 522                         cpu_relax();
 523                 break;
 524         case CT_SPINLOCKUP:
 525                 /* Must be called twice to trigger. */
 526                 spin_lock(&lock_me_up);
 527                 /* Let sparse know we intended to exit holding the lock. */
 528                 __release(&lock_me_up);
 529                 break;
 530         case CT_HUNG_TASK:
 531                 set_current_state(TASK_UNINTERRUPTIBLE);
 532                 schedule();
 533                 break;
 534         case CT_EXEC_DATA:
 535                 execute_location(data_area);
 536                 break;
 537         case CT_EXEC_STACK: {
 538                 u8 stack_area[EXEC_SIZE];
 539                 execute_location(stack_area);
 540                 break;
 541         }
 542         case CT_EXEC_KMALLOC: {
 543                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 544                 execute_location(kmalloc_area);
 545                 kfree(kmalloc_area);
 546                 break;
 547         }
 548         case CT_EXEC_VMALLOC: {
 549                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 550                 execute_location(vmalloc_area);
 551                 vfree(vmalloc_area);
 552                 break;
 553         }
 554         case CT_EXEC_USERSPACE: {
 555                 unsigned long user_addr;
 556
 557                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 558                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 559                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 560                 if (user_addr >= TASK_SIZE) {
 561                         pr_warn("Failed to allocate user memory\n");
 562                         return;
 563                 }
 564                 execute_user_location((void *)user_addr);
 565                 vm_munmap(user_addr, PAGE_SIZE);
 566                 break;
 567         }
 568         case CT_ACCESS_USERSPACE: {
 569                 unsigned long user_addr, tmp = 0;
 570                 unsigned long *ptr;
 571
 572                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 573                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 574                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 575                 if (user_addr >= TASK_SIZE) {
 576                         pr_warn("Failed to allocate user memory\n");
 577                         return;
 578                 }
 579
 580                 if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
 581                         pr_warn("copy_to_user failed\n");
 582                         vm_munmap(user_addr, PAGE_SIZE);
 583                         return;
 584                 }
 585
 586                 ptr = (unsigned long *)user_addr;
 587
 588                 pr_info("attempting bad read at %p\n", ptr);
 589                 tmp = *ptr;
 590                 tmp += 0xc0dec0de;
 591
 592                 pr_info("attempting bad write at %p\n", ptr);
 593                 *ptr = tmp;
 594
 595                 vm_munmap(user_addr, PAGE_SIZE);
 596
 597                 break;
 598         }
 599         case CT_WRITE_RO: {
 600                 unsigned long *ptr;
 601
 602                 ptr = (unsigned long *)&rodata;
 603
 604                 pr_info("attempting bad write at %p\n", ptr);
 605                 *ptr ^= 0xabcd1234;
 606
 607                 break;
 608         }
 609         case CT_WRITE_KERN: {
 610                 size_t size;
 611                 unsigned char *ptr;
 612
 613                 size = (unsigned long)do_overwritten -
 614                        (unsigned long)do_nothing;
 615                 ptr = (unsigned char *)do_overwritten;
 616
 617                 pr_info("attempting bad %zu byte write at %p\n", size, ptr);
 618                 memcpy(ptr, (unsigned char *)do_nothing, size);
 619                 flush_icache_range((unsigned long)ptr,
 620                                    (unsigned long)(ptr + size));
 621
 622                 do_overwritten();
 623                 break;
 624         }
 625         case CT_WRAP_ATOMIC: {
 626                 atomic_t under = ATOMIC_INIT(INT_MIN);
 627                 atomic_t over = ATOMIC_INIT(INT_MAX);
 628
 629                 pr_info("attempting atomic underflow\n");
 630                 atomic_dec(&under);
 631                 pr_info("attempting atomic overflow\n");
 632                 atomic_inc(&over);
 633
 634                 return;
 635         }
 636         case CT_NONE:
 637         default:
 638                 break;
 639         }
 640
 641 }
 642
 643 static void lkdtm_handler(void)
 644 {
 645         unsigned long flags;
 646         bool do_it = false;
 647
 648         spin_lock_irqsave(&count_lock, flags);
 649         count--;
 650         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 651                 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 652
 653         if (count == 0) {
 654                 do_it = true;
 655                 count = cpoint_count;
 656         }
 657         spin_unlock_irqrestore(&count_lock, flags);
 658
 659         if (do_it)
 660                 lkdtm_do_action(cptype);
 661 }
 662
 663 static int lkdtm_register_cpoint(enum cname which)
 664 {
 665         int ret;
 666
 667         cpoint = CN_INVALID;
 668         if (lkdtm.entry != NULL)
 669                 unregister_jprobe(&lkdtm);
 670
 671         switch (which) {
 672         case CN_DIRECT:
 673                 lkdtm_do_action(cptype);
 674                 return 0;
 675         case CN_INT_HARDWARE_ENTRY:
 676                 lkdtm.kp.symbol_name = "do_IRQ";
 677                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 678                 break;
 679         case CN_INT_HW_IRQ_EN:
 680                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 681                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 682                 break;
 683         case CN_INT_TASKLET_ENTRY:
 684                 lkdtm.kp.symbol_name = "tasklet_action";
 685                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 686                 break;
 687         case CN_FS_DEVRW:
 688                 lkdtm.kp.symbol_name = "ll_rw_block";
 689                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 690                 break;
 691         case CN_MEM_SWAPOUT:
 692                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 693                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 694                 break;
 695         case CN_TIMERADD:
 696                 lkdtm.kp.symbol_name = "hrtimer_start";
 697                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 698                 break;
 699         case CN_SCSI_DISPATCH_CMD:
 700                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 701                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 702                 break;
 703         case CN_IDE_CORE_CP:
 704 #ifdef CONFIG_IDE
 705                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 706                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 707 #else
 708                 pr_info("Crash point not available\n");
 709                 return -EINVAL;
 710 #endif
 711                 break;
 712         default:
 713                 pr_info("Invalid Crash Point\n");
 714                 return -EINVAL;
 715         }
 716
 717         cpoint = which;
 718         if ((ret = register_jprobe(&lkdtm)) < 0) {
 719                 pr_info("Couldn't register jprobe\n");
 720                 cpoint = CN_INVALID;
 721         }
 722
 723         return ret;
 724 }
 725
 726 static ssize_t do_register_entry(enum cname which, struct file *f,
 727                 const char __user *user_buf, size_t count, loff_t *off)
 728 {
 729         char *buf;
 730         int err;
 731
 732         if (count >= PAGE_SIZE)
 733                 return -EINVAL;
 734
 735         buf = (char *)__get_free_page(GFP_KERNEL);
 736         if (!buf)
 737                 return -ENOMEM;
 738         if (copy_from_user(buf, user_buf, count)) {
 739                 free_page((unsigned long) buf);
 740                 return -EFAULT;
 741         }
 742         /* NULL-terminate and remove enter */
 743         buf[count] = '\0';
 744         strim(buf);
 745
 746         cptype = parse_cp_type(buf, count);
 747         free_page((unsigned long) buf);
 748
 749         if (cptype == CT_NONE)
 750                 return -EINVAL;
 751
 752         err = lkdtm_register_cpoint(which);
 753         if (err < 0)
 754                 return err;
 755
 756         *off += count;
 757
 758         return count;
 759 }
 760
 761 /* Generic read callback that just prints out the available crash types */
 762 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 763                 size_t count, loff_t *off)
 764 {
 765         char *buf;
 766         int i, n, out;
 767
 768         buf = (char *)__get_free_page(GFP_KERNEL);
 769         if (buf == NULL)
 770                 return -ENOMEM;
 771
 772         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 773         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 774                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 775         buf[n] = '\0';
 776
 777         out = simple_read_from_buffer(user_buf, count, off,
 778                                       buf, n);
 779         free_page((unsigned long) buf);
 780
 781         return out;
 782 }
 783
 784 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 785 {
 786         return 0;
 787 }
 788
 789
 790 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 791                 size_t count, loff_t *off)
 792 {
 793         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 794 }
 795
 796 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 797                 size_t count, loff_t *off)
 798 {
 799         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 800 }
 801
 802 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 803                 size_t count, loff_t *off)
 804 {
 805         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 806 }
 807
 808 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 809                 size_t count, loff_t *off)
 810 {
 811         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 812 }
 813
 814 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 815                 size_t count, loff_t *off)
 816 {
 817         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 818 }
 819
 820 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 821                 size_t count, loff_t *off)
 822 {
 823         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 824 }
 825
 826 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 827                 const char __user *buf, size_t count, loff_t *off)
 828 {
 829         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 830 }
 831
 832 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 833                 size_t count, loff_t *off)
 834 {
 835         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 836 }
 837
 838 /* Special entry to just crash directly. Available without KPROBEs */
 839 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 840                 size_t count, loff_t *off)
 841 {
 842         enum ctype type;
 843         char *buf;
 844
 845         if (count >= PAGE_SIZE)
 846                 return -EINVAL;
 847         if (count < 1)
 848                 return -EINVAL;
 849
 850         buf = (char *)__get_free_page(GFP_KERNEL);
 851         if (!buf)
 852                 return -ENOMEM;
 853         if (copy_from_user(buf, user_buf, count)) {
 854                 free_page((unsigned long) buf);
 855                 return -EFAULT;
 856         }
 857         /* NULL-terminate and remove enter */
 858         buf[count] = '\0';
 859         strim(buf);
 860
 861         type = parse_cp_type(buf, count);
 862         free_page((unsigned long) buf);
 863         if (type == CT_NONE)
 864                 return -EINVAL;
 865
 866         pr_info("Performing direct entry %s\n", cp_type_to_str(type));
 867         lkdtm_do_action(type);
 868         *off += count;
 869
 870         return count;
 871 }
 872
 873 struct crash_entry {
 874         const char *name;
 875         const struct file_operations fops;
 876 };
 877
 878 static const struct crash_entry crash_entries[] = {
 879         {"DIRECT", {.read = lkdtm_debugfs_read,
 880                         .llseek = generic_file_llseek,
 881                         .open = lkdtm_debugfs_open,
 882                         .write = direct_entry} },
 883         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 884                         .llseek = generic_file_llseek,
 885                         .open = lkdtm_debugfs_open,
 886                         .write = int_hardware_entry} },
 887         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 888                         .llseek = generic_file_llseek,
 889                         .open = lkdtm_debugfs_open,
 890                         .write = int_hw_irq_en} },
 891         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 892                         .llseek = generic_file_llseek,
 893                         .open = lkdtm_debugfs_open,
 894                         .write = int_tasklet_entry} },
 895         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 896                         .llseek = generic_file_llseek,
 897                         .open = lkdtm_debugfs_open,
 898                         .write = fs_devrw_entry} },
 899         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 900                         .llseek = generic_file_llseek,
 901                         .open = lkdtm_debugfs_open,
 902                         .write = mem_swapout_entry} },
 903         {"TIMERADD", {.read = lkdtm_debugfs_read,
 904                         .llseek = generic_file_llseek,
 905                         .open = lkdtm_debugfs_open,
 906                         .write = timeradd_entry} },
 907         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 908                         .llseek = generic_file_llseek,
 909                         .open = lkdtm_debugfs_open,
 910                         .write = scsi_dispatch_cmd_entry} },
 911         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 912                         .llseek = generic_file_llseek,
 913                         .open = lkdtm_debugfs_open,
 914                         .write = ide_core_cp_entry} },
 915 };
 916
 917 static struct dentry *lkdtm_debugfs_root;
 918
 919 static int __init lkdtm_module_init(void)
 920 {
 921         int ret = -EINVAL;
 922         int n_debugfs_entries = 1; /* Assume only the direct entry */
 923         int i;
 924
 925         /* Register debugfs interface */
 926         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 927         if (!lkdtm_debugfs_root) {
 928                 pr_err("creating root dir failed\n");
 929                 return -ENODEV;
 930         }
 931
 932 #ifdef CONFIG_KPROBES
 933         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 934 #endif
 935
 936         for (i = 0; i < n_debugfs_entries; i++) {
 937                 const struct crash_entry *cur = &crash_entries[i];
 938                 struct dentry *de;
 939
 940                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 941                                 NULL, &cur->fops);
 942                 if (de == NULL) {
 943                         pr_err("could not create %s\n", cur->name);
 944                         goto out_err;
 945                 }
 946         }
 947
 948         if (lkdtm_parse_commandline() == -EINVAL) {
 949                 pr_info("Invalid command\n");
 950                 goto out_err;
 951         }
 952
 953         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 954                 ret = lkdtm_register_cpoint(cpoint);
 955                 if (ret < 0) {
 956                         pr_info("Invalid crash point %d\n", cpoint);
 957                         goto out_err;
 958                 }
 959                 pr_info("Crash point %s of type %s registered\n",
 960                         cpoint_name, cpoint_type);
 961         } else {
 962                 pr_info("No crash points registered, enable through debugfs\n");
 963         }
 964
 965         return 0;
 966
 967 out_err:
 968         debugfs_remove_recursive(lkdtm_debugfs_root);
 969         return ret;
 970 }
 971
 972 static void __exit lkdtm_module_exit(void)
 973 {
 974         debugfs_remove_recursive(lkdtm_debugfs_root);
 975
 976         unregister_jprobe(&lkdtm);
 977         pr_info("Crash point unregistered\n");
 978 }
 979
 980 module_init(lkdtm_module_init);
 981 module_exit(lkdtm_module_exit);
 982
 983 MODULE_LICENSE("GPL");
 984 MODULE_DESCRIPTION("Kprobe module for testing crash dumps");