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[fs/lustre-release.git] / libcfs / libcfs / debug.c
1 /*
2  * GPL HEADER START
3  *
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 only,
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License version 2 for more details (a copy is included
14  * in the LICENSE file that accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License
17  * version 2 along with this program; If not, see
18  * http://www.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2011, 2017, Intel Corporation.
27  */
28 /*
29  * This file is part of Lustre, http://www.lustre.org/
30  *
31  * libcfs/libcfs/debug.c
32  *
33  * Author: Phil Schwan <phil@clusterfs.com>
34  *
35  */
36
37 # define DEBUG_SUBSYSTEM S_LNET
38
39 #include <linux/module.h>
40 #include <linux/ctype.h>
41 #include <libcfs/libcfs_string.h>
42 #include <linux/kthread.h>
43 #include <linux/stacktrace.h>
44 #include <linux/utsname.h>
45 #include <linux/kallsyms.h>
46 #include "tracefile.h"
47
48 static char debug_file_name[1024];
49
50 unsigned int libcfs_subsystem_debug = ~0;
51 EXPORT_SYMBOL(libcfs_subsystem_debug);
52 module_param(libcfs_subsystem_debug, int, 0644);
53 MODULE_PARM_DESC(libcfs_subsystem_debug, "Lustre kernel debug subsystem mask");
54
55 unsigned int libcfs_debug = (D_CANTMASK | D_NETERROR | D_HA | D_CONFIG |
56                              D_IOCTL | D_LFSCK | D_TTY);
57 EXPORT_SYMBOL(libcfs_debug);
58 module_param(libcfs_debug, int, 0644);
59 MODULE_PARM_DESC(libcfs_debug, "Lustre kernel debug mask");
60
61 static int libcfs_param_debug_mb_set(const char *val,
62                                      cfs_kernel_param_arg_t *kp)
63 {
64         int rc;
65         unsigned int num;
66
67         rc = kstrtouint(val, 0, &num);
68         if (rc < 0)
69                 return rc;
70
71         num = cfs_trace_set_debug_mb(num);
72
73         *((unsigned int *)kp->arg) = num;
74         num = cfs_trace_get_debug_mb();
75         if (num)
76                 /* This value is more precise */
77                 *((unsigned int *)kp->arg) = num;
78
79         return 0;
80 }
81
82 /* While debug_mb setting look like unsigned int, in fact
83  * it needs quite a bunch of extra processing, so we define special
84  * debug_mb parameter type with corresponding methods to handle this case
85  */
86 static const struct kernel_param_ops param_ops_debug_mb = {
87         .set = libcfs_param_debug_mb_set,
88         .get = param_get_uint,
89 };
90
91 #define param_check_debug_mb(name, p) \
92                 __param_check(name, p, unsigned int)
93
94 static unsigned int libcfs_debug_mb;
95 #ifdef HAVE_KERNEL_PARAM_OPS
96 module_param(libcfs_debug_mb, debug_mb, 0644);
97 #else
98 module_param_call(libcfs_debug_mb, libcfs_param_debug_mb_set, param_get_uint,
99                   &param_ops_debug_mb, 0644);
100 #endif
101 MODULE_PARM_DESC(libcfs_debug_mb, "Total debug buffer size.");
102
103 unsigned int libcfs_printk = D_CANTMASK;
104 module_param(libcfs_printk, uint, 0644);
105 MODULE_PARM_DESC(libcfs_printk, "Lustre kernel debug console mask");
106
107 unsigned int libcfs_console_ratelimit = 1;
108 module_param(libcfs_console_ratelimit, uint, 0644);
109 MODULE_PARM_DESC(libcfs_console_ratelimit, "Lustre kernel debug console ratelimit (0 to disable)");
110
111 static int param_set_delay_minmax(const char *val,
112                                   cfs_kernel_param_arg_t *kp,
113                                   long min, long max)
114 {
115         long d;
116         int sec;
117         int rc;
118
119         rc = kstrtoint(val, 0, &sec);
120         if (rc)
121                 return -EINVAL;
122
123         /* The sysfs setting is in centiseconds */
124         d = cfs_time_seconds(sec) / 100;
125         if (d < min || d > max)
126                 return -EINVAL;
127
128         *((unsigned int *)kp->arg) = d;
129
130         return 0;
131 }
132
133 static int param_get_delay(char *buffer, cfs_kernel_param_arg_t *kp)
134 {
135         unsigned int d = *(unsigned int *)kp->arg;
136
137         param_get_byte(buffer, kp);
138         return sprintf(buffer, "%lu%c", jiffies_to_msecs(d * 10) / MSEC_PER_SEC,
139                        strnchr(buffer, PAGE_SIZE, '\n') ? '\n' : '\0');
140 }
141
142 unsigned int libcfs_console_max_delay;
143 unsigned int libcfs_console_min_delay;
144
145 static int param_set_console_max_delay(const char *val,
146                                        cfs_kernel_param_arg_t *kp)
147 {
148         return param_set_delay_minmax(val, kp,
149                                       libcfs_console_min_delay, INT_MAX);
150 }
151
152 static const struct kernel_param_ops param_ops_console_max_delay = {
153         .set = param_set_console_max_delay,
154         .get = param_get_delay,
155 };
156
157 #define param_check_console_max_delay(name, p) \
158                 __param_check(name, p, unsigned int)
159
160 #ifdef HAVE_KERNEL_PARAM_OPS
161 module_param(libcfs_console_max_delay, console_max_delay, 0644);
162 #else
163 module_param_call(libcfs_console_max_delay, param_set_console_max_delay,
164                   param_get_delay, &param_ops_console_max_delay, 0644);
165 #endif
166 MODULE_PARM_DESC(libcfs_console_max_delay, "Lustre kernel debug console max delay (jiffies)");
167
168 static int param_set_console_min_delay(const char *val,
169                                        cfs_kernel_param_arg_t *kp)
170 {
171         return param_set_delay_minmax(val, kp,
172                                       1, libcfs_console_max_delay);
173 }
174
175 static const struct kernel_param_ops param_ops_console_min_delay = {
176         .set = param_set_console_min_delay,
177         .get = param_get_delay,
178 };
179
180 #define param_check_console_min_delay(name, p) \
181                 __param_check(name, p, unsigned int)
182
183 #ifdef HAVE_KERNEL_PARAM_OPS
184 module_param(libcfs_console_min_delay, console_min_delay, 0644);
185 #else
186 module_param_call(libcfs_console_min_delay, param_set_console_min_delay,
187                   param_get_delay, &param_ops_console_min_delay, 0644);
188 #endif
189 MODULE_PARM_DESC(libcfs_console_min_delay, "Lustre kernel debug console min delay (jiffies)");
190
191 #ifndef HAVE_PARAM_SET_UINT_MINMAX
192 static int param_set_uint_minmax(const char *val,
193                                  cfs_kernel_param_arg_t *kp,
194                                  unsigned int min, unsigned int max)
195 {
196         unsigned int num;
197         int ret;
198
199         if (!val)
200                 return -EINVAL;
201
202         ret = kstrtouint(val, 0, &num);
203         if (ret < 0 || num < min || num > max)
204                 return -EINVAL;
205
206         *((unsigned int *)kp->arg) = num;
207         return 0;
208 }
209 #endif
210
211 static int param_set_uintpos(const char *val,
212                              cfs_kernel_param_arg_t *kp)
213 {
214         return param_set_uint_minmax(val, kp, 1, -1);
215 }
216
217 static const struct kernel_param_ops param_ops_uintpos = {
218         .set = param_set_uintpos,
219         .get = param_get_uint,
220 };
221
222 #define param_check_uintpos(name, p) \
223                 __param_check(name, p, unsigned int)
224
225 unsigned int libcfs_console_backoff = CDEBUG_DEFAULT_BACKOFF;
226 #ifdef HAVE_KERNEL_PARAM_OPS
227 module_param(libcfs_console_backoff, uintpos, 0644);
228 #else
229 module_param_call(libcfs_console_backoff, param_set_uintpos, param_get_uint,
230                   &param_ops_uintpos, 0644);
231 #endif
232 MODULE_PARM_DESC(libcfs_console_backoff, "Lustre kernel debug console backoff factor");
233
234 unsigned int libcfs_debug_binary = 1;
235
236 unsigned int libcfs_stack = 3 * THREAD_SIZE / 4;
237 EXPORT_SYMBOL(libcfs_stack);
238
239 unsigned int libcfs_catastrophe;
240 EXPORT_SYMBOL(libcfs_catastrophe);
241
242 unsigned int libcfs_watchdog_ratelimit = 300;
243 EXPORT_SYMBOL(libcfs_watchdog_ratelimit);
244
245 unsigned int libcfs_panic_on_lbug = 1;
246 module_param(libcfs_panic_on_lbug, uint, 0644);
247 MODULE_PARM_DESC(libcfs_panic_on_lbug, "Lustre kernel panic on LBUG");
248
249 atomic64_t libcfs_kmem = ATOMIC64_INIT(0);
250 EXPORT_SYMBOL(libcfs_kmem);
251
252 static DECLARE_COMPLETION(debug_complete);
253
254 /* We need to pass a pointer here, but elsewhere this must be a const */
255 char *libcfs_debug_file_path = LIBCFS_DEBUG_FILE_PATH_DEFAULT;
256 EXPORT_SYMBOL(libcfs_debug_file_path);
257 module_param(libcfs_debug_file_path, charp, 0644);
258 MODULE_PARM_DESC(libcfs_debug_file_path,
259                  "Path for dumping debug logs, set 'NONE' to prevent log dumping");
260
261 int libcfs_panic_in_progress;
262
263 /* libcfs_debug_token2mask() expects the returned string in lower-case */
264 static const char *libcfs_debug_subsys2str(int subsys)
265 {
266         static const char * const libcfs_debug_subsystems[] =
267                 LIBCFS_DEBUG_SUBSYS_NAMES;
268
269         if (subsys >= ARRAY_SIZE(libcfs_debug_subsystems))
270                 return NULL;
271
272         return libcfs_debug_subsystems[subsys];
273 }
274
275 /* libcfs_debug_token2mask() expects the returned string in lower-case */
276 static const char *libcfs_debug_dbg2str(int debug)
277 {
278         static const char * const libcfs_debug_masks[] =
279                 LIBCFS_DEBUG_MASKS_NAMES;
280
281         if (debug >= ARRAY_SIZE(libcfs_debug_masks))
282                 return NULL;
283
284         return libcfs_debug_masks[debug];
285 }
286
287 int
288 libcfs_debug_mask2str(char *str, int size, int mask, int is_subsys)
289 {
290         const char *(*fn)(int bit) = is_subsys ? libcfs_debug_subsys2str :
291                                                  libcfs_debug_dbg2str;
292         int len = 0;
293         const char *token;
294         int i;
295
296         if (mask == 0) {                        /* "0" */
297                 if (size > 0)
298                         str[0] = '0';
299                 len = 1;
300         } else {                                /* space-separated tokens */
301                 for (i = 0; i < 32; i++) {
302                         if ((mask & BIT(i)) == 0)
303                                 continue;
304
305                         token = fn(i);
306                         if (!token)     /* unused bit */
307                                 continue;
308
309                         if (len > 0) {          /* separator? */
310                                 if (len < size)
311                                         str[len] = ' ';
312                                 len++;
313                         }
314
315                         while (*token != 0) {
316                                 if (len < size)
317                                         str[len] = *token;
318                                 token++;
319                                 len++;
320                         }
321                 }
322         }
323
324         /* terminate 'str' */
325         if (len < size)
326                 str[len] = 0;
327         else
328                 str[size - 1] = 0;
329
330         return len;
331 }
332
333 int
334 libcfs_debug_str2mask(int *mask, const char *str, int is_subsys)
335 {
336         const char *(*fn)(int bit) = is_subsys ? libcfs_debug_subsys2str :
337                                                  libcfs_debug_dbg2str;
338         int m = 0;
339         int matched;
340         int n;
341         int t;
342
343         /* Allow a number for backwards compatibility */
344         for (n = strlen(str); n > 0; n--)
345                 if (!isspace(str[n-1]))
346                         break;
347         matched = n;
348         t = sscanf(str, "%i%n", &m, &matched);
349         if (t >= 1 && matched == n) {
350                 /* don't print warning for lctl set_param debug=0 or -1 */
351                 if (m != 0 && m != -1)
352                         CWARN("You are trying to use a numerical value for the mask - this will be deprecated in a future release.\n");
353                 *mask = m;
354                 return 0;
355         }
356
357         return cfs_str2mask(str, fn, mask, is_subsys ? 0 : D_CANTMASK,
358                             0xffffffff);
359 }
360
361 char lnet_debug_log_upcall[1024] = "/usr/lib/lustre/lnet_debug_log_upcall";
362
363 /* Upcall function once a Lustre log has been dumped.
364  *
365  * @file        path of the dumped log
366  */
367 static void libcfs_run_debug_log_upcall(char *file)
368 {
369         char *argv[3];
370         int rc;
371         static const char * const envp[] = {
372                 "HOME=/",
373                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
374                 NULL
375         };
376
377         ENTRY;
378         argv[0] = lnet_debug_log_upcall;
379
380         LASSERTF(file, "called on a null filename\n");
381         argv[1] = file; /* only need to pass the path of the file */
382
383         argv[2] = NULL;
384
385         rc = call_usermodehelper(argv[0], argv, (char **)envp, 1);
386         if (rc < 0 && rc != -ENOENT) {
387                 CERROR("Error %d invoking LNET debug log upcall %s %s; check /sys/kernel/debug/lnet/debug_log_upcall\n",
388                        rc, argv[0], argv[1]);
389         } else {
390                 CDEBUG(D_HA, "Invoked LNET debug log upcall %s %s\n",
391                        argv[0], argv[1]);
392         }
393 }
394
395 /**
396  * Dump Lustre log to ::debug_file_path by calling tracefile_dump_all_pages()
397  */
398 static void libcfs_debug_dumplog_internal(void *arg)
399 {
400         static time64_t last_dump_time;
401         time64_t current_time;
402
403         current_time = ktime_get_real_seconds();
404
405         if (strncmp(libcfs_debug_file_path, "NONE", 4) != 0 &&
406             current_time > last_dump_time) {
407                 last_dump_time = current_time;
408                 snprintf(debug_file_name, sizeof(debug_file_name) - 1,
409                          "%s.%lld.%ld", libcfs_debug_file_path,
410                          (s64)current_time, (uintptr_t)arg);
411                 pr_alert("LustreError: dumping log to %s\n", debug_file_name);
412                 cfs_tracefile_dump_all_pages(debug_file_name);
413                 libcfs_run_debug_log_upcall(debug_file_name);
414         }
415 }
416
417 static int libcfs_debug_dumplog_thread(void *arg)
418 {
419         libcfs_debug_dumplog_internal(arg);
420         complete(&debug_complete);
421         return 0;
422 }
423
424 static DEFINE_MUTEX(libcfs_debug_dumplog_lock);
425
426 void libcfs_debug_dumplog(void)
427 {
428         struct task_struct *dumper;
429
430         ENTRY;
431
432         if (mutex_trylock(&libcfs_debug_dumplog_lock) == 0)
433                 return;
434
435         /* If a previous call was interrupted, debug_complete->done
436          * might be elevated, and so we won't actually wait here.
437          * So we reinit the completion to ensure we wait for
438          * one thread to complete, though it might not be the one
439          * we start if there are overlaping thread.
440          */
441         reinit_completion(&debug_complete);
442         dumper = kthread_run(libcfs_debug_dumplog_thread,
443                              (void *)(long)current->pid,
444                              "libcfs_debug_dumper");
445         if (IS_ERR(dumper))
446                 pr_err("LustreError: cannot start log dump thread: rc = %ld\n",
447                        PTR_ERR(dumper));
448         else
449                 wait_for_completion_interruptible(&debug_complete);
450
451         mutex_unlock(&libcfs_debug_dumplog_lock);
452 }
453 EXPORT_SYMBOL(libcfs_debug_dumplog);
454
455 /* coverity[+kill] */
456 void __noreturn lbug_with_loc(struct libcfs_debug_msg_data *msgdata)
457 {
458         libcfs_catastrophe = 1;
459         libcfs_debug_msg(msgdata, "LBUG\n");
460
461         if (in_interrupt()) {
462                 panic("LBUG in interrupt.\n");
463                 /* not reached */
464         }
465
466         libcfs_debug_dumpstack(NULL);
467         if (libcfs_panic_on_lbug)
468                 panic("LBUG");
469         else
470                 libcfs_debug_dumplog();
471         set_current_state(TASK_UNINTERRUPTIBLE);
472         while (1)
473                 schedule();
474 }
475 EXPORT_SYMBOL(lbug_with_loc);
476
477 #ifdef CONFIG_STACKTRACE
478
479 #ifndef HAVE_SAVE_STACK_TRACE_TSK
480 #define save_stack_trace_tsk(tsk, trace)                                       \
481 do {                                                                           \
482         if (tsk == current)                                                    \
483                 save_stack_trace(trace);                                       \
484         else                                                                   \
485                 pr_info("No stack, save_stack_trace_tsk() not exported\n");    \
486 } while (0)
487 #endif
488
489 static void cfs_print_stack_trace(unsigned long *entries, unsigned int nr)
490 {
491         unsigned int i;
492
493         /* Prefer %pB for backtraced symbolic names since it was added in:
494          * Linux v2.6.38-6557-g0f77a8d37825
495          * vsprintf: Introduce %pB format specifier
496          */
497         for (i = 0; i < nr; i++)
498                 pr_info("[<0>] %pB\n", (void *)entries[i]);
499 }
500
501 #define MAX_ST_ENTRIES  100
502 static DEFINE_SPINLOCK(st_lock);
503
504 /* Linux v5.1-rc5 214d8ca6ee ("stacktrace: Provide common infrastructure")
505  * CONFIG_ARCH_STACKWALK indicates that save_stack_trace_tsk symbol is not
506  * exported. Use symbol_get() to find if save_stack_trace_tsk is available.
507  */
508 #ifdef CONFIG_ARCH_STACKWALK
509 typedef unsigned int (stack_trace_save_tsk_t)(struct task_struct *task,
510                                               unsigned long *store,
511                                               unsigned int size,
512                                               unsigned int skipnr);
513 static stack_trace_save_tsk_t *task_dump_stack;
514 #endif
515
516 void __init cfs_debug_init(void)
517 {
518 #ifdef CONFIG_ARCH_STACKWALK
519         task_dump_stack = (void *)
520                         cfs_kallsyms_lookup_name("stack_trace_save_tsk");
521
522 #endif
523 }
524
525 static void libcfs_call_trace(struct task_struct *tsk)
526 {
527         static unsigned long entries[MAX_ST_ENTRIES];
528 #ifdef CONFIG_ARCH_STACKWALK
529         unsigned int nr_entries;
530
531         spin_lock(&st_lock);
532         pr_info("Pid: %d, comm: %.20s %s %s\n", tsk->pid, tsk->comm,
533                 init_utsname()->release, init_utsname()->version);
534         pr_info("Call Trace TBD:\n");
535         if (task_dump_stack) {
536                 nr_entries = task_dump_stack(tsk, entries, MAX_ST_ENTRIES, 0);
537                 cfs_print_stack_trace(entries, nr_entries);
538         }
539         spin_unlock(&st_lock);
540 #else
541         struct stack_trace trace;
542
543         trace.nr_entries = 0;
544         trace.max_entries = MAX_ST_ENTRIES;
545         trace.entries = entries;
546         trace.skip = 0;
547
548         spin_lock(&st_lock);
549         pr_info("Pid: %d, comm: %.20s %s %s\n", tsk->pid, tsk->comm,
550                 init_utsname()->release, init_utsname()->version);
551         pr_info("Call Trace:\n");
552         save_stack_trace_tsk(tsk, &trace);
553         cfs_print_stack_trace(trace.entries, trace.nr_entries);
554         spin_unlock(&st_lock);
555 #endif
556 }
557
558 #else /* !CONFIG_STACKTRACE */
559
560 #ifdef CONFIG_X86
561 #include <linux/nmi.h>
562 #include <asm/stacktrace.h>
563
564 #ifdef HAVE_STACKTRACE_OPS
565 static int print_trace_stack(void *data, char *name)
566 {
567         printk(" <%s> ", name);
568         return 0;
569 }
570
571 #ifdef STACKTRACE_OPS_ADDRESS_RETURN_INT
572 static int
573 #else
574 static void
575 #endif
576 print_trace_address(void *data, unsigned long addr, int reliable)
577 {
578         char fmt[32];
579
580         touch_nmi_watchdog();
581         sprintf(fmt, " [<%016lx>] %s%%s\n", addr, reliable ? "" : "? ");
582         __print_symbol(fmt, addr);
583 #ifdef STACKTRACE_OPS_ADDRESS_RETURN_INT
584         return 0;
585 #endif
586 }
587
588 static const struct stacktrace_ops print_trace_ops = {
589         .stack          = print_trace_stack,
590         .address        = print_trace_address,
591         .walk_stack     = print_context_stack,
592 };
593 #endif /* HAVE_STACKTRACE_OPS */
594
595 static void libcfs_call_trace(struct task_struct *tsk)
596 {
597 #ifdef HAVE_STACKTRACE_OPS
598         printk("Pid: %d, comm: %.20s\n", tsk->pid, tsk->comm);
599         printk("\nCall Trace:\n");
600         dump_trace(tsk, NULL, NULL, 0, &print_trace_ops, NULL);
601         printk("\n");
602 #else /* !HAVE_STACKTRACE_OPS */
603         if (tsk == current)
604                 dump_stack();
605         else
606                 CWARN("can't show stack: kernel doesn't export show_task\n");
607 #endif /* HAVE_STACKTRACE_OPS */
608 }
609
610 #else /* !CONFIG_X86 */
611
612 static void libcfs_call_trace(struct task_struct *tsk)
613 {
614         if (tsk == current)
615                 dump_stack();
616         else
617                 CWARN("can't show stack: kernel doesn't export show_task\n");
618 }
619
620 #endif /* CONFIG_X86 */
621
622 #endif /* CONFIG_STACKTRACE */
623
624 void libcfs_debug_dumpstack(struct task_struct *tsk)
625 {
626         libcfs_call_trace(tsk ?: current);
627 }
628 EXPORT_SYMBOL(libcfs_debug_dumpstack);
629
630 static int panic_notifier(struct notifier_block *self, unsigned long unused1,
631                           void *unused2)
632 {
633         if (libcfs_panic_in_progress)
634                 return 0;
635
636         libcfs_panic_in_progress = 1;
637         mb();
638
639 #ifdef LNET_DUMP_ON_PANIC
640         /* This is currently disabled because it spews far too much to the
641          * console on the rare cases it is ever triggered. */
642
643         if (in_interrupt()) {
644                 cfs_trace_debug_print();
645         } else {
646                 libcfs_debug_dumplog_internal((void *)(long)current->pid);
647         }
648 #endif
649         return 0;
650 }
651
652 static struct notifier_block libcfs_panic_notifier = {
653         .notifier_call          = panic_notifier,
654         .next                   = NULL,
655         .priority               = 10000,
656 };
657
658 static void libcfs_register_panic_notifier(void)
659 {
660         atomic_notifier_chain_register(&panic_notifier_list,
661                                        &libcfs_panic_notifier);
662 }
663
664 static void libcfs_unregister_panic_notifier(void)
665 {
666         atomic_notifier_chain_unregister(&panic_notifier_list,
667                                          &libcfs_panic_notifier);
668 }
669
670 int libcfs_debug_init(unsigned long bufsize)
671 {
672         unsigned int max = libcfs_debug_mb;
673         int rc = 0;
674
675         if (libcfs_console_max_delay <= 0 || /* not set by user or */
676             libcfs_console_min_delay <= 0 || /* set to invalid values */
677             libcfs_console_min_delay >= libcfs_console_max_delay) {
678                 libcfs_console_max_delay = CDEBUG_DEFAULT_MAX_DELAY;
679                 libcfs_console_min_delay = CDEBUG_DEFAULT_MIN_DELAY;
680         }
681
682         /* If libcfs_debug_mb is uninitialized then just make the
683          * total buffers smp_num_cpus * TCD_MAX_PAGES
684          */
685         if (max < num_possible_cpus()) {
686                 max = TCD_MAX_PAGES;
687         } else {
688                 max = (max / num_possible_cpus());
689                 max <<= (20 - PAGE_SHIFT);
690         }
691
692         rc = cfs_tracefile_init(max);
693         if (rc)
694                 return rc;
695
696         libcfs_register_panic_notifier();
697         kernel_param_lock(THIS_MODULE);
698         if (libcfs_debug_mb == 0)
699                 libcfs_debug_mb = cfs_trace_get_debug_mb();
700         kernel_param_unlock(THIS_MODULE);
701         return rc;
702 }
703
704 int libcfs_debug_cleanup(void)
705 {
706         libcfs_unregister_panic_notifier();
707         kernel_param_lock(THIS_MODULE);
708         cfs_tracefile_exit();
709         kernel_param_unlock(THIS_MODULE);
710         return 0;
711 }
712
713 int libcfs_debug_clear_buffer(void)
714 {
715         cfs_trace_flush_pages();
716         return 0;
717 }
718
719 /* Debug markers, although printed by S_LNET should not be be marked as such. */
720 #undef DEBUG_SUBSYSTEM
721 #define DEBUG_SUBSYSTEM S_UNDEFINED
722 int libcfs_debug_mark_buffer(const char *text)
723 {
724         CDEBUG(D_TRACE,
725                "**************************************************\n");
726         LCONSOLE(D_WARNING, "DEBUG MARKER: %s\n", text);
727         CDEBUG(D_TRACE,
728                "**************************************************\n");
729
730         return 0;
731 }
732
733 #undef DEBUG_SUBSYSTEM
734 #define DEBUG_SUBSYSTEM S_LNET