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);
  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