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