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