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