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, *again;
 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                 pr_info("Attempting bad write to freed memory at %p\n",
 432                         &base[offset]);
 433                 kfree(base);
 434                 base[offset] = 0x0abcdef0;
 435                 /* Attempt to notice the overwrite. */
 436                 again = kmalloc(len, GFP_KERNEL);
 437                 kfree(again);
 438                 if (again != base)
 439                         pr_info("Hmm, didn't get the same memory range.\n");
 440
 441                 break;
 442         }
 443         case CT_READ_AFTER_FREE: {
 444                 int *base, *val, saw;
 445                 size_t len = 1024;
 446                 /*
 447                  * The slub allocator uses the first word to store the free
 448                  * pointer in some configurations. Use the middle of the
 449                  * allocation to avoid running into the freelist
 450                  */
 451                 size_t offset = (len / sizeof(*base)) / 2;
 452
 453                 base = kmalloc(len, GFP_KERNEL);
 454                 if (!base)
 455                         break;
 456
 457                 val = kmalloc(len, GFP_KERNEL);
 458                 if (!val)
 459                         break;
 460
 461                 *val = 0x12345678;
 462                 base[offset] = *val;
 463                 pr_info("Value in memory before free: %x\n", base[offset]);
 464
 465                 kfree(base);
 466
 467                 pr_info("Attempting bad read from freed memory\n");
 468                 saw = base[offset];
 469                 if (saw != *val) {
 470                         /* Good! Poisoning happened, so declare a win. */
 471                         pr_info("Memory correctly poisoned (%x)\n", saw);
 472                         BUG();
 473                 }
 474                 pr_info("Memory was not poisoned\n");
 475
 476                 kfree(val);
 477                 break;
 478         }
 479         case CT_WRITE_BUDDY_AFTER_FREE: {
 480                 unsigned long p = __get_free_page(GFP_KERNEL);
 481                 if (!p)
 482                         break;
 483                 pr_info("Writing to the buddy page before free\n");
 484                 memset((void *)p, 0x3, PAGE_SIZE);
 485                 free_page(p);
 486                 schedule();
 487                 pr_info("Attempting bad write to the buddy page after free\n");
 488                 memset((void *)p, 0x78, PAGE_SIZE);
 489                 /* Attempt to notice the overwrite. */
 490                 p = __get_free_page(GFP_KERNEL);
 491                 free_page(p);
 492                 schedule();
 493
 494                 break;
 495         }
 496         case CT_READ_BUDDY_AFTER_FREE: {
 497                 unsigned long p = __get_free_page(GFP_KERNEL);
 498                 int saw, *val = kmalloc(1024, GFP_KERNEL);
 499                 int *base;
 500
 501                 if (!p)
 502                         break;
 503
 504                 if (!val)
 505                         break;
 506
 507                 base = (int *)p;
 508
 509                 *val = 0x12345678;
 510                 base[0] = *val;
 511                 pr_info("Value in memory before free: %x\n", base[0]);
 512                 free_page(p);
 513                 pr_info("Attempting to read from freed memory\n");
 514                 saw = base[0];
 515                 if (saw != *val) {
 516                         /* Good! Poisoning happened, so declare a win. */
 517                         pr_info("Memory correctly poisoned (%x)\n", saw);
 518                         BUG();
 519                 }
 520                 pr_info("Buddy page was not poisoned\n");
 521
 522                 kfree(val);
 523                 break;
 524         }
 525         case CT_SOFTLOCKUP:
 526                 preempt_disable();
 527                 for (;;)
 528                         cpu_relax();
 529                 break;
 530         case CT_HARDLOCKUP:
 531                 local_irq_disable();
 532                 for (;;)
 533                         cpu_relax();
 534                 break;
 535         case CT_SPINLOCKUP:
 536                 /* Must be called twice to trigger. */
 537                 spin_lock(&lock_me_up);
 538                 /* Let sparse know we intended to exit holding the lock. */
 539                 __release(&lock_me_up);
 540                 break;
 541         case CT_HUNG_TASK:
 542                 set_current_state(TASK_UNINTERRUPTIBLE);
 543                 schedule();
 544                 break;
 545         case CT_EXEC_DATA:
 546                 execute_location(data_area);
 547                 break;
 548         case CT_EXEC_STACK: {
 549                 u8 stack_area[EXEC_SIZE];
 550                 execute_location(stack_area);
 551                 break;
 552         }
 553         case CT_EXEC_KMALLOC: {
 554                 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
 555                 execute_location(kmalloc_area);
 556                 kfree(kmalloc_area);
 557                 break;
 558         }
 559         case CT_EXEC_VMALLOC: {
 560                 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
 561                 execute_location(vmalloc_area);
 562                 vfree(vmalloc_area);
 563                 break;
 564         }
 565         case CT_EXEC_USERSPACE: {
 566                 unsigned long user_addr;
 567
 568                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 569                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 570                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 571                 if (user_addr >= TASK_SIZE) {
 572                         pr_warn("Failed to allocate user memory\n");
 573                         return;
 574                 }
 575                 execute_user_location((void *)user_addr);
 576                 vm_munmap(user_addr, PAGE_SIZE);
 577                 break;
 578         }
 579         case CT_ACCESS_USERSPACE: {
 580                 unsigned long user_addr, tmp = 0;
 581                 unsigned long *ptr;
 582
 583                 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
 584                                     PROT_READ | PROT_WRITE | PROT_EXEC,
 585                                     MAP_ANONYMOUS | MAP_PRIVATE, 0);
 586                 if (user_addr >= TASK_SIZE) {
 587                         pr_warn("Failed to allocate user memory\n");
 588                         return;
 589                 }
 590
 591                 if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
 592                         pr_warn("copy_to_user failed\n");
 593                         vm_munmap(user_addr, PAGE_SIZE);
 594                         return;
 595                 }
 596
 597                 ptr = (unsigned long *)user_addr;
 598
 599                 pr_info("attempting bad read at %p\n", ptr);
 600                 tmp = *ptr;
 601                 tmp += 0xc0dec0de;
 602
 603                 pr_info("attempting bad write at %p\n", ptr);
 604                 *ptr = tmp;
 605
 606                 vm_munmap(user_addr, PAGE_SIZE);
 607
 608                 break;
 609         }
 610         case CT_WRITE_RO: {
 611                 unsigned long *ptr;
 612
 613                 ptr = (unsigned long *)&rodata;
 614
 615                 pr_info("attempting bad write at %p\n", ptr);
 616                 *ptr ^= 0xabcd1234;
 617
 618                 break;
 619         }
 620         case CT_WRITE_KERN: {
 621                 size_t size;
 622                 unsigned char *ptr;
 623
 624                 size = (unsigned long)do_overwritten -
 625                        (unsigned long)do_nothing;
 626                 ptr = (unsigned char *)do_overwritten;
 627
 628                 pr_info("attempting bad %zu byte write at %p\n", size, ptr);
 629                 memcpy(ptr, (unsigned char *)do_nothing, size);
 630                 flush_icache_range((unsigned long)ptr,
 631                                    (unsigned long)(ptr + size));
 632
 633                 do_overwritten();
 634                 break;
 635         }
 636         case CT_WRAP_ATOMIC: {
 637                 atomic_t under = ATOMIC_INIT(INT_MIN);
 638                 atomic_t over = ATOMIC_INIT(INT_MAX);
 639
 640                 pr_info("attempting atomic underflow\n");
 641                 atomic_dec(&under);
 642                 pr_info("attempting atomic overflow\n");
 643                 atomic_inc(&over);
 644
 645                 return;
 646         }
 647         case CT_NONE:
 648         default:
 649                 break;
 650         }
 651
 652 }
 653
 654 static void lkdtm_handler(void)
 655 {
 656         unsigned long flags;
 657         bool do_it = false;
 658
 659         spin_lock_irqsave(&count_lock, flags);
 660         count--;
 661         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 662                 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 663
 664         if (count == 0) {
 665                 do_it = true;
 666                 count = cpoint_count;
 667         }
 668         spin_unlock_irqrestore(&count_lock, flags);
 669
 670         if (do_it)
 671                 lkdtm_do_action(cptype);
 672 }
 673
 674 static int lkdtm_register_cpoint(enum cname which)
 675 {
 676         int ret;
 677
 678         cpoint = CN_INVALID;
 679         if (lkdtm.entry != NULL)
 680                 unregister_jprobe(&lkdtm);
 681
 682         switch (which) {
 683         case CN_DIRECT:
 684                 lkdtm_do_action(cptype);
 685                 return 0;
 686         case CN_INT_HARDWARE_ENTRY:
 687                 lkdtm.kp.symbol_name = "do_IRQ";
 688                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 689                 break;
 690         case CN_INT_HW_IRQ_EN:
 691                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 692                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 693                 break;
 694         case CN_INT_TASKLET_ENTRY:
 695                 lkdtm.kp.symbol_name = "tasklet_action";
 696                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 697                 break;
 698         case CN_FS_DEVRW:
 699                 lkdtm.kp.symbol_name = "ll_rw_block";
 700                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 701                 break;
 702         case CN_MEM_SWAPOUT:
 703                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 704                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 705                 break;
 706         case CN_TIMERADD:
 707                 lkdtm.kp.symbol_name = "hrtimer_start";
 708                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 709                 break;
 710         case CN_SCSI_DISPATCH_CMD:
 711                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 712                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 713                 break;
 714         case CN_IDE_CORE_CP:
 715 #ifdef CONFIG_IDE
 716                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 717                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 718 #else
 719                 pr_info("Crash point not available\n");
 720                 return -EINVAL;
 721 #endif
 722                 break;
 723         default:
 724                 pr_info("Invalid Crash Point\n");
 725                 return -EINVAL;
 726         }
 727
 728         cpoint = which;
 729         if ((ret = register_jprobe(&lkdtm)) < 0) {
 730                 pr_info("Couldn't register jprobe\n");
 731                 cpoint = CN_INVALID;
 732         }
 733
 734         return ret;
 735 }
 736
 737 static ssize_t do_register_entry(enum cname which, struct file *f,
 738                 const char __user *user_buf, size_t count, loff_t *off)
 739 {
 740         char *buf;
 741         int err;
 742
 743         if (count >= PAGE_SIZE)
 744                 return -EINVAL;
 745
 746         buf = (char *)__get_free_page(GFP_KERNEL);
 747         if (!buf)
 748                 return -ENOMEM;
 749         if (copy_from_user(buf, user_buf, count)) {
 750                 free_page((unsigned long) buf);
 751                 return -EFAULT;
 752         }
 753         /* NULL-terminate and remove enter */
 754         buf[count] = '\0';
 755         strim(buf);
 756
 757         cptype = parse_cp_type(buf, count);
 758         free_page((unsigned long) buf);
 759
 760         if (cptype == CT_NONE)
 761                 return -EINVAL;
 762
 763         err = lkdtm_register_cpoint(which);
 764         if (err < 0)
 765                 return err;
 766
 767         *off += count;
 768
 769         return count;
 770 }
 771
 772 /* Generic read callback that just prints out the available crash types */
 773 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 774                 size_t count, loff_t *off)
 775 {
 776         char *buf;
 777         int i, n, out;
 778
 779         buf = (char *)__get_free_page(GFP_KERNEL);
 780         if (buf == NULL)
 781                 return -ENOMEM;
 782
 783         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 784         for (i = 0; i < ARRAY_SIZE(cp_type); i++)
 785                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
 786         buf[n] = '\0';
 787
 788         out = simple_read_from_buffer(user_buf, count, off,
 789                                       buf, n);
 790         free_page((unsigned long) buf);
 791
 792         return out;
 793 }
 794
 795 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 796 {
 797         return 0;
 798 }
 799
 800
 801 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
 802                 size_t count, loff_t *off)
 803 {
 804         return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
 805 }
 806
 807 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
 808                 size_t count, loff_t *off)
 809 {
 810         return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
 811 }
 812
 813 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
 814                 size_t count, loff_t *off)
 815 {
 816         return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
 817 }
 818
 819 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
 820                 size_t count, loff_t *off)
 821 {
 822         return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
 823 }
 824
 825 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
 826                 size_t count, loff_t *off)
 827 {
 828         return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
 829 }
 830
 831 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
 832                 size_t count, loff_t *off)
 833 {
 834         return do_register_entry(CN_TIMERADD, f, buf, count, off);
 835 }
 836
 837 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
 838                 const char __user *buf, size_t count, loff_t *off)
 839 {
 840         return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
 841 }
 842
 843 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
 844                 size_t count, loff_t *off)
 845 {
 846         return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
 847 }
 848
 849 /* Special entry to just crash directly. Available without KPROBEs */
 850 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 851                 size_t count, loff_t *off)
 852 {
 853         enum ctype type;
 854         char *buf;
 855
 856         if (count >= PAGE_SIZE)
 857                 return -EINVAL;
 858         if (count < 1)
 859                 return -EINVAL;
 860
 861         buf = (char *)__get_free_page(GFP_KERNEL);
 862         if (!buf)
 863                 return -ENOMEM;
 864         if (copy_from_user(buf, user_buf, count)) {
 865                 free_page((unsigned long) buf);
 866                 return -EFAULT;
 867         }
 868         /* NULL-terminate and remove enter */
 869         buf[count] = '\0';
 870         strim(buf);
 871
 872         type = parse_cp_type(buf, count);
 873         free_page((unsigned long) buf);
 874         if (type == CT_NONE)
 875                 return -EINVAL;
 876
 877         pr_info("Performing direct entry %s\n", cp_type_to_str(type));
 878         lkdtm_do_action(type);
 879         *off += count;
 880
 881         return count;
 882 }
 883
 884 struct crash_entry {
 885         const char *name;
 886         const struct file_operations fops;
 887 };
 888
 889 static const struct crash_entry crash_entries[] = {
 890         {"DIRECT", {.read = lkdtm_debugfs_read,
 891                         .llseek = generic_file_llseek,
 892                         .open = lkdtm_debugfs_open,
 893                         .write = direct_entry} },
 894         {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
 895                         .llseek = generic_file_llseek,
 896                         .open = lkdtm_debugfs_open,
 897                         .write = int_hardware_entry} },
 898         {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
 899                         .llseek = generic_file_llseek,
 900                         .open = lkdtm_debugfs_open,
 901                         .write = int_hw_irq_en} },
 902         {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
 903                         .llseek = generic_file_llseek,
 904                         .open = lkdtm_debugfs_open,
 905                         .write = int_tasklet_entry} },
 906         {"FS_DEVRW", {.read = lkdtm_debugfs_read,
 907                         .llseek = generic_file_llseek,
 908                         .open = lkdtm_debugfs_open,
 909                         .write = fs_devrw_entry} },
 910         {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
 911                         .llseek = generic_file_llseek,
 912                         .open = lkdtm_debugfs_open,
 913                         .write = mem_swapout_entry} },
 914         {"TIMERADD", {.read = lkdtm_debugfs_read,
 915                         .llseek = generic_file_llseek,
 916                         .open = lkdtm_debugfs_open,
 917                         .write = timeradd_entry} },
 918         {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
 919                         .llseek = generic_file_llseek,
 920                         .open = lkdtm_debugfs_open,
 921                         .write = scsi_dispatch_cmd_entry} },
 922         {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
 923                         .llseek = generic_file_llseek,
 924                         .open = lkdtm_debugfs_open,
 925                         .write = ide_core_cp_entry} },
 926 };
 927
 928 static struct dentry *lkdtm_debugfs_root;
 929
 930 static int __init lkdtm_module_init(void)
 931 {
 932         int ret = -EINVAL;
 933         int n_debugfs_entries = 1; /* Assume only the direct entry */
 934         int i;
 935
 936         /* Register debugfs interface */
 937         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 938         if (!lkdtm_debugfs_root) {
 939                 pr_err("creating root dir failed\n");
 940                 return -ENODEV;
 941         }
 942
 943 #ifdef CONFIG_KPROBES
 944         n_debugfs_entries = ARRAY_SIZE(crash_entries);
 945 #endif
 946
 947         for (i = 0; i < n_debugfs_entries; i++) {
 948                 const struct crash_entry *cur = &crash_entries[i];
 949                 struct dentry *de;
 950
 951                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 952                                 NULL, &cur->fops);
 953                 if (de == NULL) {
 954                         pr_err("could not create %s\n", cur->name);
 955                         goto out_err;
 956                 }
 957         }
 958
 959         if (lkdtm_parse_commandline() == -EINVAL) {
 960                 pr_info("Invalid command\n");
 961                 goto out_err;
 962         }
 963
 964         if (cpoint != CN_INVALID && cptype != CT_NONE) {
 965                 ret = lkdtm_register_cpoint(cpoint);
 966                 if (ret < 0) {
 967                         pr_info("Invalid crash point %d\n", cpoint);
 968                         goto out_err;
 969                 }
 970                 pr_info("Crash point %s of type %s registered\n",
 971                         cpoint_name, cpoint_type);
 972         } else {
 973                 pr_info("No crash points registered, enable through debugfs\n");
 974         }
 975
 976         return 0;
 977
 978 out_err:
 979         debugfs_remove_recursive(lkdtm_debugfs_root);
 980         return ret;
 981 }
 982
 983 static void __exit lkdtm_module_exit(void)
 984 {
 985         debugfs_remove_recursive(lkdtm_debugfs_root);
 986
 987         unregister_jprobe(&lkdtm);
 988         pr_info("Crash point unregistered\n");
 989 }
 990
 991 module_init(lkdtm_module_init);
 992 module_exit(lkdtm_module_exit);
 993
 994 MODULE_LICENSE("GPL");
 995 MODULE_DESCRIPTION("Kprobe module for testing crash dumps");