Root/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
34#include <linux/kernel.h>
35#include <linux/fs.h>
36#include <linux/module.h>
37#include <linux/buffer_head.h>
38#include <linux/kprobes.h>
39#include <linux/list.h>
40#include <linux/init.h>
41#include <linux/interrupt.h>
42#include <linux/hrtimer.h>
43#include <linux/slab.h>
44#include <scsi/scsi_cmnd.h>
45#include <linux/debugfs.h>
46
47#ifdef CONFIG_IDE
48#include <linux/ide.h>
49#endif
50
51#define DEFAULT_COUNT 10
52#define REC_NUM_DEFAULT 10
53
54enum cname {
55    CN_INVALID,
56    CN_INT_HARDWARE_ENTRY,
57    CN_INT_HW_IRQ_EN,
58    CN_INT_TASKLET_ENTRY,
59    CN_FS_DEVRW,
60    CN_MEM_SWAPOUT,
61    CN_TIMERADD,
62    CN_SCSI_DISPATCH_CMD,
63    CN_IDE_CORE_CP,
64    CN_DIRECT,
65};
66
67enum ctype {
68    CT_NONE,
69    CT_PANIC,
70    CT_BUG,
71    CT_EXCEPTION,
72    CT_LOOP,
73    CT_OVERFLOW,
74    CT_CORRUPT_STACK,
75    CT_UNALIGNED_LOAD_STORE_WRITE,
76    CT_OVERWRITE_ALLOCATION,
77    CT_WRITE_AFTER_FREE,
78    CT_SOFTLOCKUP,
79    CT_HARDLOCKUP,
80    CT_HUNG_TASK,
81};
82
83static char* cp_name[] = {
84    "INT_HARDWARE_ENTRY",
85    "INT_HW_IRQ_EN",
86    "INT_TASKLET_ENTRY",
87    "FS_DEVRW",
88    "MEM_SWAPOUT",
89    "TIMERADD",
90    "SCSI_DISPATCH_CMD",
91    "IDE_CORE_CP",
92    "DIRECT",
93};
94
95static char* cp_type[] = {
96    "PANIC",
97    "BUG",
98    "EXCEPTION",
99    "LOOP",
100    "OVERFLOW",
101    "CORRUPT_STACK",
102    "UNALIGNED_LOAD_STORE_WRITE",
103    "OVERWRITE_ALLOCATION",
104    "WRITE_AFTER_FREE",
105    "SOFTLOCKUP",
106    "HARDLOCKUP",
107    "HUNG_TASK",
108};
109
110static struct jprobe lkdtm;
111
112static int lkdtm_parse_commandline(void);
113static void lkdtm_handler(void);
114
115static char* cpoint_name;
116static char* cpoint_type;
117static int cpoint_count = DEFAULT_COUNT;
118static int recur_count = REC_NUM_DEFAULT;
119
120static enum cname cpoint = CN_INVALID;
121static enum ctype cptype = CT_NONE;
122static int count = DEFAULT_COUNT;
123static DEFINE_SPINLOCK(count_lock);
124
125module_param(recur_count, int, 0644);
126MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
127                 "default is 10");
128module_param(cpoint_name, charp, 0444);
129MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
130module_param(cpoint_type, charp, 0444);
131MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
132                "hitting the crash point");
133module_param(cpoint_count, int, 0644);
134MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
135                "crash point is to be hit to trigger action");
136
137static unsigned int jp_do_irq(unsigned int irq)
138{
139    lkdtm_handler();
140    jprobe_return();
141    return 0;
142}
143
144static irqreturn_t jp_handle_irq_event(unsigned int irq,
145                       struct irqaction *action)
146{
147    lkdtm_handler();
148    jprobe_return();
149    return 0;
150}
151
152static void jp_tasklet_action(struct softirq_action *a)
153{
154    lkdtm_handler();
155    jprobe_return();
156}
157
158static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
159{
160    lkdtm_handler();
161    jprobe_return();
162}
163
164struct scan_control;
165
166static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
167                         struct zone *zone,
168                         struct scan_control *sc)
169{
170    lkdtm_handler();
171    jprobe_return();
172    return 0;
173}
174
175static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
176                const enum hrtimer_mode mode)
177{
178    lkdtm_handler();
179    jprobe_return();
180    return 0;
181}
182
183static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
184{
185    lkdtm_handler();
186    jprobe_return();
187    return 0;
188}
189
190#ifdef CONFIG_IDE
191int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
192            struct block_device *bdev, unsigned int cmd,
193            unsigned long arg)
194{
195    lkdtm_handler();
196    jprobe_return();
197    return 0;
198}
199#endif
200
201/* Return the crashpoint number or NONE if the name is invalid */
202static enum ctype parse_cp_type(const char *what, size_t count)
203{
204    int i;
205
206    for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
207        if (!strcmp(what, cp_type[i]))
208            return i + 1;
209    }
210
211    return CT_NONE;
212}
213
214static const char *cp_type_to_str(enum ctype type)
215{
216    if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
217        return "None";
218
219    return cp_type[type - 1];
220}
221
222static const char *cp_name_to_str(enum cname name)
223{
224    if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
225        return "INVALID";
226
227    return cp_name[name - 1];
228}
229
230
231static int lkdtm_parse_commandline(void)
232{
233    int i;
234    unsigned long flags;
235
236    if (cpoint_count < 1 || recur_count < 1)
237        return -EINVAL;
238
239    spin_lock_irqsave(&count_lock, flags);
240    count = cpoint_count;
241    spin_unlock_irqrestore(&count_lock, flags);
242
243    /* No special parameters */
244    if (!cpoint_type && !cpoint_name)
245        return 0;
246
247    /* Neither or both of these need to be set */
248    if (!cpoint_type || !cpoint_name)
249        return -EINVAL;
250
251    cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
252    if (cptype == CT_NONE)
253        return -EINVAL;
254
255    for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
256        if (!strcmp(cpoint_name, cp_name[i])) {
257            cpoint = i + 1;
258            return 0;
259        }
260    }
261
262    /* Could not find a valid crash point */
263    return -EINVAL;
264}
265
266static int recursive_loop(int a)
267{
268    char buf[1024];
269
270    memset(buf,0xFF,1024);
271    recur_count--;
272    if (!recur_count)
273        return 0;
274    else
275            return recursive_loop(a);
276}
277
278static void lkdtm_do_action(enum ctype which)
279{
280    switch (which) {
281    case CT_PANIC:
282        panic("dumptest");
283        break;
284    case CT_BUG:
285        BUG();
286        break;
287    case CT_EXCEPTION:
288        *((int *) 0) = 0;
289        break;
290    case CT_LOOP:
291        for (;;)
292            ;
293        break;
294    case CT_OVERFLOW:
295        (void) recursive_loop(0);
296        break;
297    case CT_CORRUPT_STACK: {
298        volatile u32 data[8];
299        volatile u32 *p = data;
300
301        p[12] = 0x12345678;
302        break;
303    }
304    case CT_UNALIGNED_LOAD_STORE_WRITE: {
305        static u8 data[5] __attribute__((aligned(4))) = {1, 2,
306                3, 4, 5};
307        u32 *p;
308        u32 val = 0x12345678;
309
310        p = (u32 *)(data + 1);
311        if (*p == 0)
312            val = 0x87654321;
313        *p = val;
314         break;
315    }
316    case CT_OVERWRITE_ALLOCATION: {
317        size_t len = 1020;
318        u32 *data = kmalloc(len, GFP_KERNEL);
319
320        data[1024 / sizeof(u32)] = 0x12345678;
321        kfree(data);
322        break;
323    }
324    case CT_WRITE_AFTER_FREE: {
325        size_t len = 1024;
326        u32 *data = kmalloc(len, GFP_KERNEL);
327
328        kfree(data);
329        schedule();
330        memset(data, 0x78, len);
331        break;
332    }
333    case CT_SOFTLOCKUP:
334        preempt_disable();
335        for (;;)
336            cpu_relax();
337        break;
338    case CT_HARDLOCKUP:
339        local_irq_disable();
340        for (;;)
341            cpu_relax();
342        break;
343    case CT_HUNG_TASK:
344        set_current_state(TASK_UNINTERRUPTIBLE);
345        schedule();
346        break;
347    case CT_NONE:
348    default:
349        break;
350    }
351
352}
353
354static void lkdtm_handler(void)
355{
356    unsigned long flags;
357    bool do_it = false;
358
359    spin_lock_irqsave(&count_lock, flags);
360    count--;
361    printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
362            cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
363
364    if (count == 0) {
365        do_it = true;
366        count = cpoint_count;
367    }
368    spin_unlock_irqrestore(&count_lock, flags);
369
370    if (do_it)
371        lkdtm_do_action(cptype);
372}
373
374static int lkdtm_register_cpoint(enum cname which)
375{
376    int ret;
377
378    cpoint = CN_INVALID;
379    if (lkdtm.entry != NULL)
380        unregister_jprobe(&lkdtm);
381
382    switch (which) {
383    case CN_DIRECT:
384        lkdtm_do_action(cptype);
385        return 0;
386    case CN_INT_HARDWARE_ENTRY:
387        lkdtm.kp.symbol_name = "do_IRQ";
388        lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
389        break;
390    case CN_INT_HW_IRQ_EN:
391        lkdtm.kp.symbol_name = "handle_IRQ_event";
392        lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
393        break;
394    case CN_INT_TASKLET_ENTRY:
395        lkdtm.kp.symbol_name = "tasklet_action";
396        lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
397        break;
398    case CN_FS_DEVRW:
399        lkdtm.kp.symbol_name = "ll_rw_block";
400        lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
401        break;
402    case CN_MEM_SWAPOUT:
403        lkdtm.kp.symbol_name = "shrink_inactive_list";
404        lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
405        break;
406    case CN_TIMERADD:
407        lkdtm.kp.symbol_name = "hrtimer_start";
408        lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
409        break;
410    case CN_SCSI_DISPATCH_CMD:
411        lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
412        lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
413        break;
414    case CN_IDE_CORE_CP:
415#ifdef CONFIG_IDE
416        lkdtm.kp.symbol_name = "generic_ide_ioctl";
417        lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
418#else
419        printk(KERN_INFO "lkdtm: Crash point not available\n");
420        return -EINVAL;
421#endif
422        break;
423    default:
424        printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
425        return -EINVAL;
426    }
427
428    cpoint = which;
429    if ((ret = register_jprobe(&lkdtm)) < 0) {
430        printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
431        cpoint = CN_INVALID;
432    }
433
434    return ret;
435}
436
437static ssize_t do_register_entry(enum cname which, struct file *f,
438        const char __user *user_buf, size_t count, loff_t *off)
439{
440    char *buf;
441    int err;
442
443    if (count >= PAGE_SIZE)
444        return -EINVAL;
445
446    buf = (char *)__get_free_page(GFP_KERNEL);
447    if (!buf)
448        return -ENOMEM;
449    if (copy_from_user(buf, user_buf, count)) {
450        free_page((unsigned long) buf);
451        return -EFAULT;
452    }
453    /* NULL-terminate and remove enter */
454    buf[count] = '\0';
455    strim(buf);
456
457    cptype = parse_cp_type(buf, count);
458    free_page((unsigned long) buf);
459
460    if (cptype == CT_NONE)
461        return -EINVAL;
462
463    err = lkdtm_register_cpoint(which);
464    if (err < 0)
465        return err;
466
467    *off += count;
468
469    return count;
470}
471
472/* Generic read callback that just prints out the available crash types */
473static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
474        size_t count, loff_t *off)
475{
476    char *buf;
477    int i, n, out;
478
479    buf = (char *)__get_free_page(GFP_KERNEL);
480    if (buf == NULL)
481        return -ENOMEM;
482
483    n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
484    for (i = 0; i < ARRAY_SIZE(cp_type); i++)
485        n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
486    buf[n] = '\0';
487
488    out = simple_read_from_buffer(user_buf, count, off,
489                      buf, n);
490    free_page((unsigned long) buf);
491
492    return out;
493}
494
495static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
496{
497    return 0;
498}
499
500
501static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
502        size_t count, loff_t *off)
503{
504    return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
505}
506
507static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
508        size_t count, loff_t *off)
509{
510    return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
511}
512
513static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
514        size_t count, loff_t *off)
515{
516    return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
517}
518
519static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
520        size_t count, loff_t *off)
521{
522    return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
523}
524
525static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
526        size_t count, loff_t *off)
527{
528    return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
529}
530
531static ssize_t timeradd_entry(struct file *f, const char __user *buf,
532        size_t count, loff_t *off)
533{
534    return do_register_entry(CN_TIMERADD, f, buf, count, off);
535}
536
537static ssize_t scsi_dispatch_cmd_entry(struct file *f,
538        const char __user *buf, size_t count, loff_t *off)
539{
540    return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
541}
542
543static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
544        size_t count, loff_t *off)
545{
546    return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
547}
548
549/* Special entry to just crash directly. Available without KPROBEs */
550static ssize_t direct_entry(struct file *f, const char __user *user_buf,
551        size_t count, loff_t *off)
552{
553    enum ctype type;
554    char *buf;
555
556    if (count >= PAGE_SIZE)
557        return -EINVAL;
558    if (count < 1)
559        return -EINVAL;
560
561    buf = (char *)__get_free_page(GFP_KERNEL);
562    if (!buf)
563        return -ENOMEM;
564    if (copy_from_user(buf, user_buf, count)) {
565        free_page((unsigned long) buf);
566        return -EFAULT;
567    }
568    /* NULL-terminate and remove enter */
569    buf[count] = '\0';
570    strim(buf);
571
572    type = parse_cp_type(buf, count);
573    free_page((unsigned long) buf);
574    if (type == CT_NONE)
575        return -EINVAL;
576
577    printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
578            cp_type_to_str(type));
579    lkdtm_do_action(type);
580    *off += count;
581
582    return count;
583}
584
585struct crash_entry {
586    const char *name;
587    const struct file_operations fops;
588};
589
590static const struct crash_entry crash_entries[] = {
591    {"DIRECT", {.read = lkdtm_debugfs_read,
592            .llseek = generic_file_llseek,
593            .open = lkdtm_debugfs_open,
594            .write = direct_entry} },
595    {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
596            .llseek = generic_file_llseek,
597            .open = lkdtm_debugfs_open,
598            .write = int_hardware_entry} },
599    {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
600            .llseek = generic_file_llseek,
601            .open = lkdtm_debugfs_open,
602            .write = int_hw_irq_en} },
603    {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
604            .llseek = generic_file_llseek,
605            .open = lkdtm_debugfs_open,
606            .write = int_tasklet_entry} },
607    {"FS_DEVRW", {.read = lkdtm_debugfs_read,
608            .llseek = generic_file_llseek,
609            .open = lkdtm_debugfs_open,
610            .write = fs_devrw_entry} },
611    {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
612            .llseek = generic_file_llseek,
613            .open = lkdtm_debugfs_open,
614            .write = mem_swapout_entry} },
615    {"TIMERADD", {.read = lkdtm_debugfs_read,
616            .llseek = generic_file_llseek,
617            .open = lkdtm_debugfs_open,
618            .write = timeradd_entry} },
619    {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
620            .llseek = generic_file_llseek,
621            .open = lkdtm_debugfs_open,
622            .write = scsi_dispatch_cmd_entry} },
623    {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
624            .llseek = generic_file_llseek,
625            .open = lkdtm_debugfs_open,
626            .write = ide_core_cp_entry} },
627};
628
629static struct dentry *lkdtm_debugfs_root;
630
631static int __init lkdtm_module_init(void)
632{
633    int ret = -EINVAL;
634    int n_debugfs_entries = 1; /* Assume only the direct entry */
635    int i;
636
637    /* Register debugfs interface */
638    lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
639    if (!lkdtm_debugfs_root) {
640        printk(KERN_ERR "lkdtm: creating root dir failed\n");
641        return -ENODEV;
642    }
643
644#ifdef CONFIG_KPROBES
645    n_debugfs_entries = ARRAY_SIZE(crash_entries);
646#endif
647
648    for (i = 0; i < n_debugfs_entries; i++) {
649        const struct crash_entry *cur = &crash_entries[i];
650        struct dentry *de;
651
652        de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
653                NULL, &cur->fops);
654        if (de == NULL) {
655            printk(KERN_ERR "lkdtm: could not create %s\n",
656                    cur->name);
657            goto out_err;
658        }
659    }
660
661    if (lkdtm_parse_commandline() == -EINVAL) {
662        printk(KERN_INFO "lkdtm: Invalid command\n");
663        goto out_err;
664    }
665
666    if (cpoint != CN_INVALID && cptype != CT_NONE) {
667        ret = lkdtm_register_cpoint(cpoint);
668        if (ret < 0) {
669            printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
670                    cpoint);
671            goto out_err;
672        }
673        printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
674                cpoint_name, cpoint_type);
675    } else {
676        printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
677    }
678
679    return 0;
680
681out_err:
682    debugfs_remove_recursive(lkdtm_debugfs_root);
683    return ret;
684}
685
686static void __exit lkdtm_module_exit(void)
687{
688    debugfs_remove_recursive(lkdtm_debugfs_root);
689
690    unregister_jprobe(&lkdtm);
691    printk(KERN_INFO "lkdtm: Crash point unregistered\n");
692}
693
694module_init(lkdtm_module_init);
695module_exit(lkdtm_module_exit);
696
697MODULE_LICENSE("GPL");
698

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