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_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
jp_do_irq(unsigned int irq)177 static unsigned int jp_do_irq(unsigned int irq)
178 {
179 lkdtm_handler();
180 jprobe_return();
181 return 0;
182 }
183
jp_handle_irq_event(unsigned int irq,struct irqaction * action)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
jp_tasklet_action(struct softirq_action * a)192 static void jp_tasklet_action(struct softirq_action *a)
193 {
194 lkdtm_handler();
195 jprobe_return();
196 }
197
jp_ll_rw_block(int rw,int nr,struct buffer_head * bhs[])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
jp_shrink_inactive_list(unsigned long max_scan,struct zone * zone,struct scan_control * sc)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
jp_hrtimer_start(struct hrtimer * timer,ktime_t tim,const enum hrtimer_mode mode)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
jp_scsi_dispatch_cmd(struct scsi_cmnd * cmd)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
jp_generic_ide_ioctl(ide_drive_t * drive,struct file * file,struct block_device * bdev,unsigned int cmd,unsigned long arg)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 */
parse_cp_type(const char * what,size_t count)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
cp_type_to_str(enum ctype type)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
cp_name_to_str(enum cname name)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
lkdtm_parse_commandline(void)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
recursive_loop(int remaining)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
do_nothing(void)318 static void do_nothing(void)
319 {
320 return;
321 }
322
323 /* Must immediately follow do_nothing for size calculuations to work out. */
do_overwritten(void)324 static void do_overwritten(void)
325 {
326 pr_info("do_overwritten wasn't overwritten!\n");
327 return;
328 }
329
corrupt_stack(void)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
execute_location(void * dst)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
execute_user_location(void * dst)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
lkdtm_do_action(enum ctype which)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
lkdtm_handler(void)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
lkdtm_register_cpoint(enum cname which)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
do_register_entry(enum cname which,struct file * f,const char __user * user_buf,size_t count,loff_t * off)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 */
lkdtm_debugfs_read(struct file * f,char __user * user_buf,size_t count,loff_t * off)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
lkdtm_debugfs_open(struct inode * inode,struct file * file)673 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
674 {
675 return 0;
676 }
677
678
int_hardware_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
int_hw_irq_en(struct file * f,const char __user * buf,size_t count,loff_t * off)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
int_tasklet_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
fs_devrw_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
mem_swapout_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
timeradd_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
scsi_dispatch_cmd_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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
ide_core_cp_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)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 */
direct_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)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
lkdtm_module_init(void)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
lkdtm_module_exit(void)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");
874