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  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * libcfs/libcfs/debug.c
  33  *
  34  * Author: Phil Schwan <phil@clusterfs.com>
  35  *
  36  */
  37
  38 # define DEBUG_SUBSYSTEM S_LNET
  39
  40 #include <linux/module.h>
  41 #include <linux/ctype.h>
  42 #include <libcfs/libcfs_string.h>
  43 #include <linux/kthread.h>
  44 #include <linux/stacktrace.h>
  45 #include <linux/utsname.h>
  46 #include <linux/kallsyms.h>
  47 #include "tracefile.h"
  48
  49 static char debug_file_name[1024];
  50
  51 unsigned int libcfs_subsystem_debug = ~0;
  52 EXPORT_SYMBOL(libcfs_subsystem_debug);
  53 module_param(libcfs_subsystem_debug, int, 0644);
  54 MODULE_PARM_DESC(libcfs_subsystem_debug, "Lustre kernel debug subsystem mask");
  55
  56 unsigned int libcfs_debug = (D_CANTMASK | D_NETERROR | D_HA | D_CONFIG |
  57                              D_IOCTL | D_LFSCK | D_TTY);
  58 EXPORT_SYMBOL(libcfs_debug);
  59 module_param(libcfs_debug, int, 0644);
  60 MODULE_PARM_DESC(libcfs_debug, "Lustre kernel debug mask");
  61
  62 static int libcfs_param_debug_mb_set(const char *val,
  63                                      cfs_kernel_param_arg_t *kp)
  64 {
  65         int rc;
  66         unsigned int num;
  67
  68         rc = kstrtouint(val, 0, &num);
  69         if (rc < 0)
  70                 return rc;
  71
  72         num = cfs_trace_set_debug_mb(num);
  73
  74         *((unsigned int *)kp->arg) = num;
  75         num = cfs_trace_get_debug_mb();
  76         if (num)
  77                 /* This value is more precise */
  78                 *((unsigned int *)kp->arg) = num;
  79
  80         return 0;
  81 }
  82
  83 /* While debug_mb setting look like unsigned int, in fact
  84  * it needs quite a bunch of extra processing, so we define special
  85  * debug_mb parameter type with corresponding methods to handle this case
  86  */
  87 static const struct kernel_param_ops param_ops_debug_mb = {
  88         .set = libcfs_param_debug_mb_set,
  89         .get = param_get_uint,
  90 };
  91
  92 #define param_check_debug_mb(name, p) \
  93                 __param_check(name, p, unsigned int)
  94
  95 static unsigned int libcfs_debug_mb;
  96 #ifdef HAVE_KERNEL_PARAM_OPS
  97 module_param(libcfs_debug_mb, debug_mb, 0644);
  98 #else
  99 module_param_call(libcfs_debug_mb, libcfs_param_debug_mb_set, param_get_uint,
 100                   &param_ops_debug_mb, 0644);
 101 #endif
 102 MODULE_PARM_DESC(libcfs_debug_mb, "Total debug buffer size.");
 103
 104 unsigned int libcfs_printk = D_CANTMASK;
 105 module_param(libcfs_printk, uint, 0644);
 106 MODULE_PARM_DESC(libcfs_printk, "Lustre kernel debug console mask");
 107
 108 unsigned int libcfs_console_ratelimit = 1;
 109 module_param(libcfs_console_ratelimit, uint, 0644);
 110 MODULE_PARM_DESC(libcfs_console_ratelimit, "Lustre kernel debug console ratelimit (0 to disable)");
 111
 112 static int param_set_delay_minmax(const char *val,
 113                                   cfs_kernel_param_arg_t *kp,
 114                                   long min, long max)
 115 {
 116         long d;
 117         int sec;
 118         int rc;
 119
 120         rc = kstrtoint(val, 0, &sec);
 121         if (rc)
 122                 return -EINVAL;
 123
 124         /* The sysfs setting is in centiseconds */
 125         d = cfs_time_seconds(sec) / 100;
 126         if (d < min || d > max)
 127                 return -EINVAL;
 128
 129         *((unsigned int *)kp->arg) = d;
 130
 131         return 0;
 132 }
 133
 134 static int param_get_delay(char *buffer, cfs_kernel_param_arg_t *kp)
 135 {
 136         unsigned int d = *(unsigned int *)kp->arg;
 137
 138         param_get_byte(buffer, kp);
 139         return sprintf(buffer, "%lu%c", jiffies_to_msecs(d * 10) / MSEC_PER_SEC,
 140                        strnchr(buffer, PAGE_SIZE, '\n') ? '\n' : '\0');
 141 }
 142
 143 unsigned int libcfs_console_max_delay;
 144 unsigned int libcfs_console_min_delay;
 145
 146 static int param_set_console_max_delay(const char *val,
 147                                        cfs_kernel_param_arg_t *kp)
 148 {
 149         return param_set_delay_minmax(val, kp,
 150                                       libcfs_console_min_delay, INT_MAX);
 151 }
 152
 153 static const struct kernel_param_ops param_ops_console_max_delay = {
 154         .set = param_set_console_max_delay,
 155         .get = param_get_delay,
 156 };
 157
 158 #define param_check_console_max_delay(name, p) \
 159                 __param_check(name, p, unsigned int)
 160
 161 #ifdef HAVE_KERNEL_PARAM_OPS
 162 module_param(libcfs_console_max_delay, console_max_delay, 0644);
 163 #else
 164 module_param_call(libcfs_console_max_delay, param_set_console_max_delay,
 165                   param_get_delay, &param_ops_console_max_delay, 0644);
 166 #endif
 167 MODULE_PARM_DESC(libcfs_console_max_delay, "Lustre kernel debug console max delay (jiffies)");
 168
 169 static int param_set_console_min_delay(const char *val,
 170                                        cfs_kernel_param_arg_t *kp)
 171 {
 172         return param_set_delay_minmax(val, kp,
 173                                       1, libcfs_console_max_delay);
 174 }
 175
 176 static const struct kernel_param_ops param_ops_console_min_delay = {
 177         .set = param_set_console_min_delay,
 178         .get = param_get_delay,
 179 };
 180
 181 #define param_check_console_min_delay(name, p) \
 182                 __param_check(name, p, unsigned int)
 183
 184 #ifdef HAVE_KERNEL_PARAM_OPS
 185 module_param(libcfs_console_min_delay, console_min_delay, 0644);
 186 #else
 187 module_param_call(libcfs_console_min_delay, param_set_console_min_delay,
 188                   param_get_delay, &param_ops_console_min_delay, 0644);
 189 #endif
 190 MODULE_PARM_DESC(libcfs_console_min_delay, "Lustre kernel debug console min delay (jiffies)");
 191
 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
 210 static int param_set_uintpos(const char *val,
 211                              cfs_kernel_param_arg_t *kp)
 212 {
 213         return param_set_uint_minmax(val, kp, 1, -1);
 214 }
 215
 216 static const struct kernel_param_ops param_ops_uintpos = {
 217         .set = param_set_uintpos,
 218         .get = param_get_uint,
 219 };
 220
 221 #define param_check_uintpos(name, p) \
 222                 __param_check(name, p, unsigned int)
 223
 224 unsigned int libcfs_console_backoff = CDEBUG_DEFAULT_BACKOFF;
 225 #ifdef HAVE_KERNEL_PARAM_OPS
 226 module_param(libcfs_console_backoff, uintpos, 0644);
 227 #else
 228 module_param_call(libcfs_console_backoff, param_set_uintpos, param_get_uint,
 229                   &param_ops_uintpos, 0644);
 230 #endif
 231 MODULE_PARM_DESC(libcfs_console_backoff, "Lustre kernel debug console backoff factor");
 232
 233 unsigned int libcfs_debug_binary = 1;
 234
 235 unsigned int libcfs_stack = 3 * THREAD_SIZE / 4;
 236 EXPORT_SYMBOL(libcfs_stack);
 237
 238 unsigned int libcfs_catastrophe;
 239 EXPORT_SYMBOL(libcfs_catastrophe);
 240
 241 unsigned int libcfs_watchdog_ratelimit = 300;
 242 EXPORT_SYMBOL(libcfs_watchdog_ratelimit);
 243
 244 unsigned int libcfs_panic_on_lbug = 1;
 245 module_param(libcfs_panic_on_lbug, uint, 0644);
 246 MODULE_PARM_DESC(libcfs_panic_on_lbug, "Lustre kernel panic on LBUG");
 247
 248 atomic64_t libcfs_kmem = ATOMIC64_INIT(0);
 249 EXPORT_SYMBOL(libcfs_kmem);
 250
 251 static DECLARE_COMPLETION(debug_complete);
 252
 253 /* We need to pass a pointer here, but elsewhere this must be a const */
 254 char *libcfs_debug_file_path = LIBCFS_DEBUG_FILE_PATH_DEFAULT;
 255 EXPORT_SYMBOL(libcfs_debug_file_path);
 256 module_param(libcfs_debug_file_path, charp, 0644);
 257 MODULE_PARM_DESC(libcfs_debug_file_path,
 258                  "Path for dumping debug logs, set 'NONE' to prevent log dumping");
 259
 260 int libcfs_panic_in_progress;
 261
 262 /* libcfs_debug_token2mask() expects the returned string in lower-case */
 263 static const char *libcfs_debug_subsys2str(int subsys)
 264 {
 265         static const char * const libcfs_debug_subsystems[] =
 266                 LIBCFS_DEBUG_SUBSYS_NAMES;
 267
 268         if (subsys >= ARRAY_SIZE(libcfs_debug_subsystems))
 269                 return NULL;
 270
 271         return libcfs_debug_subsystems[subsys];
 272 }
 273
 274 /* libcfs_debug_token2mask() expects the returned string in lower-case */
 275 static const char *libcfs_debug_dbg2str(int debug)
 276 {
 277         static const char * const libcfs_debug_masks[] =
 278                 LIBCFS_DEBUG_MASKS_NAMES;
 279
 280         if (debug >= ARRAY_SIZE(libcfs_debug_masks))
 281                 return NULL;
 282
 283         return libcfs_debug_masks[debug];
 284 }
 285
 286 int
 287 libcfs_debug_mask2str(char *str, int size, int mask, int is_subsys)
 288 {
 289         const char *(*fn)(int bit) = is_subsys ? libcfs_debug_subsys2str :
 290                                                  libcfs_debug_dbg2str;
 291         int len = 0;
 292         const char *token;
 293         int i;
 294
 295         if (mask == 0) {                        /* "0" */
 296                 if (size > 0)
 297                         str[0] = '0';
 298                 len = 1;
 299         } else {                                /* space-separated tokens */
 300                 for (i = 0; i < 32; i++) {
 301                         if ((mask & BIT(i)) == 0)
 302                                 continue;
 303
 304                         token = fn(i);
 305                         if (!token)     /* unused bit */
 306                                 continue;
 307
 308                         if (len > 0) {          /* separator? */
 309                                 if (len < size)
 310                                         str[len] = ' ';
 311                                 len++;
 312                         }
 313
 314                         while (*token != 0) {
 315                                 if (len < size)
 316                                         str[len] = *token;
 317                                 token++;
 318                                 len++;
 319                         }
 320                 }
 321         }
 322
 323         /* terminate 'str' */
 324         if (len < size)
 325                 str[len] = 0;
 326         else
 327                 str[size - 1] = 0;
 328
 329         return len;
 330 }
 331
 332 int
 333 libcfs_debug_str2mask(int *mask, const char *str, int is_subsys)
 334 {
 335         const char *(*fn)(int bit) = is_subsys ? libcfs_debug_subsys2str :
 336                                                  libcfs_debug_dbg2str;
 337         int m = 0;
 338         int matched;
 339         int n;
 340         int t;
 341
 342         /* Allow a number for backwards compatibility */
 343         for (n = strlen(str); n > 0; n--)
 344                 if (!isspace(str[n-1]))
 345                         break;
 346         matched = n;
 347         t = sscanf(str, "%i%n", &m, &matched);
 348         if (t >= 1 && matched == n) {
 349                 /* don't print warning for lctl set_param debug=0 or -1 */
 350                 if (m != 0 && m != -1)
 351                         CWARN("You are trying to use a numerical value for the mask - this will be deprecated in a future release.\n");
 352                 *mask = m;
 353                 return 0;
 354         }
 355
 356         return cfs_str2mask(str, fn, mask, is_subsys ? 0 : D_CANTMASK,
 357                             0xffffffff);
 358 }
 359
 360 char lnet_debug_log_upcall[1024] = "/usr/lib/lustre/lnet_debug_log_upcall";
 361
 362 /* Upcall function once a Lustre log has been dumped.
 363  *
 364  * @file        path of the dumped log
 365  */
 366 static void libcfs_run_debug_log_upcall(char *file)
 367 {
 368         char *argv[3];
 369         int rc;
 370         static const char * const envp[] = {
 371                 "HOME=/",
 372                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
 373                 NULL
 374         };
 375
 376         ENTRY;
 377         argv[0] = lnet_debug_log_upcall;
 378
 379         LASSERTF(file, "called on a null filename\n");
 380         argv[1] = file; /* only need to pass the path of the file */
 381
 382         argv[2] = NULL;
 383
 384         rc = call_usermodehelper(argv[0], argv, (char **)envp, 1);
 385         if (rc < 0 && rc != -ENOENT) {
 386                 CERROR("Error %d invoking LNET debug log upcall %s %s; check /sys/kernel/debug/lnet/debug_log_upcall\n",
 387                        rc, argv[0], argv[1]);
 388         } else {
 389                 CDEBUG(D_HA, "Invoked LNET debug log upcall %s %s\n",
 390                        argv[0], argv[1]);
 391         }
 392 }
 393
 394 /**
 395  * Dump Lustre log to ::debug_file_path by calling tracefile_dump_all_pages()
 396  */
 397 static void libcfs_debug_dumplog_internal(void *arg)
 398 {
 399         static time64_t last_dump_time;
 400         time64_t current_time;
 401
 402         current_time = ktime_get_real_seconds();
 403
 404         if (strncmp(libcfs_debug_file_path, "NONE", 4) != 0 &&
 405             current_time > last_dump_time) {
 406                 last_dump_time = current_time;
 407                 snprintf(debug_file_name, sizeof(debug_file_name) - 1,
 408                          "%s.%lld.%ld", libcfs_debug_file_path,
 409                          (s64)current_time, (uintptr_t)arg);
 410                 pr_alert("LustreError: dumping log to %s\n", debug_file_name);
 411                 cfs_tracefile_dump_all_pages(debug_file_name);
 412                 libcfs_run_debug_log_upcall(debug_file_name);
 413         }
 414 }
 415
 416 static int libcfs_debug_dumplog_thread(void *arg)
 417 {
 418         libcfs_debug_dumplog_internal(arg);
 419         complete(&debug_complete);
 420         return 0;
 421 }
 422
 423 static DEFINE_MUTEX(libcfs_debug_dumplog_lock);
 424
 425 void libcfs_debug_dumplog(void)
 426 {
 427         struct task_struct *dumper;
 428
 429         ENTRY;
 430
 431         if (mutex_trylock(&libcfs_debug_dumplog_lock) == 0)
 432                 return;
 433
 434         /* If a previous call was interrupted, debug_complete->done
 435          * might be elevated, and so we won't actually wait here.
 436          * So we reinit the completion to ensure we wait for
 437          * one thread to complete, though it might not be the one
 438          * we start if there are overlaping thread.
 439          */
 440         reinit_completion(&debug_complete);
 441         dumper = kthread_run(libcfs_debug_dumplog_thread,
 442                              (void *)(long)current->pid,
 443                              "libcfs_debug_dumper");
 444         if (IS_ERR(dumper))
 445                 pr_err("LustreError: cannot start log dump thread: rc = %ld\n",
 446                        PTR_ERR(dumper));
 447         else
 448                 wait_for_completion_interruptible(&debug_complete);
 449
 450         mutex_unlock(&libcfs_debug_dumplog_lock);
 451 }
 452 EXPORT_SYMBOL(libcfs_debug_dumplog);
 453
 454 /* coverity[+kill] */
 455 void __noreturn lbug_with_loc(struct libcfs_debug_msg_data *msgdata)
 456 {
 457         libcfs_catastrophe = 1;
 458         libcfs_debug_msg(msgdata, "LBUG\n");
 459
 460         if (in_interrupt()) {
 461                 panic("LBUG in interrupt.\n");
 462                 /* not reached */
 463         }
 464
 465         libcfs_debug_dumpstack(NULL);
 466         if (libcfs_panic_on_lbug)
 467                 panic("LBUG");
 468         else
 469                 libcfs_debug_dumplog();
 470         set_current_state(TASK_UNINTERRUPTIBLE);
 471         while (1)
 472                 schedule();
 473 }
 474 EXPORT_SYMBOL(lbug_with_loc);
 475
 476 #ifdef CONFIG_STACKTRACE
 477
 478 #ifndef HAVE_SAVE_STACK_TRACE_TSK
 479 #define save_stack_trace_tsk(tsk, trace)                                       \
 480 do {                                                                           \
 481         if (tsk == current)                                                    \
 482                 save_stack_trace(trace);                                       \
 483         else                                                                   \
 484                 pr_info("No stack, save_stack_trace_tsk() not exported\n");    \
 485 } while (0)
 486 #endif
 487
 488 static void cfs_print_stack_trace(unsigned long *entries, unsigned int nr)
 489 {
 490         unsigned int i;
 491
 492         /* Prefer %pB for backtraced symbolic names since it was added in:
 493          * Linux v2.6.38-6557-g0f77a8d37825
 494          * vsprintf: Introduce %pB format specifier
 495          */
 496         for (i = 0; i < nr; i++)
 497                 pr_info("[<0>] %pB\n", (void *)entries[i]);
 498 }
 499
 500 #define MAX_ST_ENTRIES  100
 501 static DEFINE_SPINLOCK(st_lock);
 502
 503 /* Linux v5.1-rc5 214d8ca6ee ("stacktrace: Provide common infrastructure")
 504  * CONFIG_ARCH_STACKWALK indicates that save_stack_trace_tsk symbol is not
 505  * exported. Use symbol_get() to find if save_stack_trace_tsk is available.
 506  */
 507 #ifdef CONFIG_ARCH_STACKWALK
 508 typedef unsigned int (stack_trace_save_tsk_t)(struct task_struct *task,
 509                                               unsigned long *store,
 510                                               unsigned int size,
 511                                               unsigned int skipnr);
 512 static stack_trace_save_tsk_t *task_dump_stack;
 513 #endif
 514
 515 void __init cfs_debug_init(void)
 516 {
 517 #ifdef CONFIG_ARCH_STACKWALK
 518         task_dump_stack = (void *)
 519                         kallsyms_lookup_name("stack_trace_save_tsk");
 520
 521 #endif
 522 }
 523
 524 static void libcfs_call_trace(struct task_struct *tsk)
 525 {
 526         static unsigned long entries[MAX_ST_ENTRIES];
 527 #ifdef CONFIG_ARCH_STACKWALK
 528         unsigned int nr_entries;
 529
 530         spin_lock(&st_lock);
 531         pr_info("Pid: %d, comm: %.20s %s %s\n", tsk->pid, tsk->comm,
 532                 init_utsname()->release, init_utsname()->version);
 533         pr_info("Call Trace TBD:\n");
 534         if (task_dump_stack) {
 535                 nr_entries = task_dump_stack(tsk, entries, MAX_ST_ENTRIES, 0);
 536                 cfs_print_stack_trace(entries, nr_entries);
 537         }
 538         spin_unlock(&st_lock);
 539 #else
 540         struct stack_trace trace;
 541
 542         trace.nr_entries = 0;
 543         trace.max_entries = MAX_ST_ENTRIES;
 544         trace.entries = entries;
 545         trace.skip = 0;
 546
 547         spin_lock(&st_lock);
 548         pr_info("Pid: %d, comm: %.20s %s %s\n", tsk->pid, tsk->comm,
 549                 init_utsname()->release, init_utsname()->version);
 550         pr_info("Call Trace:\n");
 551         save_stack_trace_tsk(tsk, &trace);
 552         cfs_print_stack_trace(trace.entries, trace.nr_entries);
 553         spin_unlock(&st_lock);
 554 #endif
 555 }
 556
 557 #else /* !CONFIG_STACKTRACE */
 558
 559 #ifdef CONFIG_X86
 560 #include <linux/nmi.h>
 561 #include <asm/stacktrace.h>
 562
 563 #ifdef HAVE_STACKTRACE_OPS
 564 static int print_trace_stack(void *data, char *name)
 565 {
 566         printk(" <%s> ", name);
 567         return 0;
 568 }
 569
 570 #ifdef STACKTRACE_OPS_ADDRESS_RETURN_INT
 571 static int
 572 #else
 573 static void
 574 #endif
 575 print_trace_address(void *data, unsigned long addr, int reliable)
 576 {
 577         char fmt[32];
 578
 579         touch_nmi_watchdog();
 580         sprintf(fmt, " [<%016lx>] %s%%s\n", addr, reliable ? "" : "? ");
 581         __print_symbol(fmt, addr);
 582 #ifdef STACKTRACE_OPS_ADDRESS_RETURN_INT
 583         return 0;
 584 #endif
 585 }
 586
 587 static const struct stacktrace_ops print_trace_ops = {
 588         .stack          = print_trace_stack,
 589         .address        = print_trace_address,
 590         .walk_stack     = print_context_stack,
 591 };
 592 #endif /* HAVE_STACKTRACE_OPS */
 593
 594 static void libcfs_call_trace(struct task_struct *tsk)
 595 {
 596 #ifdef HAVE_STACKTRACE_OPS
 597         printk("Pid: %d, comm: %.20s\n", tsk->pid, tsk->comm);
 598         printk("\nCall Trace:\n");
 599         dump_trace(tsk, NULL, NULL, 0, &print_trace_ops, NULL);
 600         printk("\n");
 601 #else /* !HAVE_STACKTRACE_OPS */
 602         if (tsk == current)
 603                 dump_stack();
 604         else
 605                 CWARN("can't show stack: kernel doesn't export show_task\n");
 606 #endif /* HAVE_STACKTRACE_OPS */
 607 }
 608
 609 #else /* !CONFIG_X86 */
 610
 611 static void libcfs_call_trace(struct task_struct *tsk)
 612 {
 613         if (tsk == current)
 614                 dump_stack();
 615         else
 616                 CWARN("can't show stack: kernel doesn't export show_task\n");
 617 }
 618
 619 #endif /* CONFIG_X86 */
 620
 621 #endif /* CONFIG_STACKTRACE */
 622
 623 void libcfs_debug_dumpstack(struct task_struct *tsk)
 624 {
 625         libcfs_call_trace(tsk ?: current);
 626 }
 627 EXPORT_SYMBOL(libcfs_debug_dumpstack);
 628
 629 static int panic_notifier(struct notifier_block *self, unsigned long unused1,
 630                           void *unused2)
 631 {
 632         if (libcfs_panic_in_progress)
 633                 return 0;
 634
 635         libcfs_panic_in_progress = 1;
 636         mb();
 637
 638 #ifdef LNET_DUMP_ON_PANIC
 639         /* This is currently disabled because it spews far too much to the
 640          * console on the rare cases it is ever triggered. */
 641
 642         if (in_interrupt()) {
 643                 cfs_trace_debug_print();
 644         } else {
 645                 libcfs_debug_dumplog_internal((void *)(long)current->pid);
 646         }
 647 #endif
 648         return 0;
 649 }
 650
 651 static struct notifier_block libcfs_panic_notifier = {
 652         .notifier_call          = panic_notifier,
 653         .next                   = NULL,
 654         .priority               = 10000,
 655 };
 656
 657 static void libcfs_register_panic_notifier(void)
 658 {
 659         atomic_notifier_chain_register(&panic_notifier_list,
 660                                        &libcfs_panic_notifier);
 661 }
 662
 663 static void libcfs_unregister_panic_notifier(void)
 664 {
 665         atomic_notifier_chain_unregister(&panic_notifier_list,
 666                                          &libcfs_panic_notifier);
 667 }
 668
 669 int libcfs_debug_init(unsigned long bufsize)
 670 {
 671         unsigned int max = libcfs_debug_mb;
 672         int rc = 0;
 673
 674         if (libcfs_console_max_delay <= 0 || /* not set by user or */
 675             libcfs_console_min_delay <= 0 || /* set to invalid values */
 676             libcfs_console_min_delay >= libcfs_console_max_delay) {
 677                 libcfs_console_max_delay = CDEBUG_DEFAULT_MAX_DELAY;
 678                 libcfs_console_min_delay = CDEBUG_DEFAULT_MIN_DELAY;
 679         }
 680
 681         /* If libcfs_debug_mb is uninitialized then just make the
 682          * total buffers smp_num_cpus * TCD_MAX_PAGES
 683          */
 684         if (max < num_possible_cpus()) {
 685                 max = TCD_MAX_PAGES;
 686         } else {
 687                 max = (max / num_possible_cpus());
 688                 max <<= (20 - PAGE_SHIFT);
 689         }
 690
 691         rc = cfs_tracefile_init(max);
 692         if (rc)
 693                 return rc;
 694
 695         libcfs_register_panic_notifier();
 696         kernel_param_lock(THIS_MODULE);
 697         if (libcfs_debug_mb == 0)
 698                 libcfs_debug_mb = cfs_trace_get_debug_mb();
 699         kernel_param_unlock(THIS_MODULE);
 700         return rc;
 701 }
 702
 703 int libcfs_debug_cleanup(void)
 704 {
 705         libcfs_unregister_panic_notifier();
 706         kernel_param_lock(THIS_MODULE);
 707         cfs_tracefile_exit();
 708         kernel_param_unlock(THIS_MODULE);
 709         return 0;
 710 }
 711
 712 int libcfs_debug_clear_buffer(void)
 713 {
 714         cfs_trace_flush_pages();
 715         return 0;
 716 }
 717
 718 /* Debug markers, although printed by S_LNET should not be be marked as such. */
 719 #undef DEBUG_SUBSYSTEM
 720 #define DEBUG_SUBSYSTEM S_UNDEFINED
 721 int libcfs_debug_mark_buffer(const char *text)
 722 {
 723         CDEBUG(D_TRACE,
 724                "**************************************************\n");
 725         LCONSOLE(D_WARNING, "DEBUG MARKER: %s\n", text);
 726         CDEBUG(D_TRACE,
 727                "**************************************************\n");
 728
 729         return 0;
 730 }
 731
 732 #undef DEBUG_SUBSYSTEM
 733 #define DEBUG_SUBSYSTEM S_LNET
 734
 735 long libcfs_log_return(struct libcfs_debug_msg_data *msgdata, long rc)
 736 {
 737         libcfs_debug_msg(msgdata, "Process leaving (rc=%lu : %ld : %lx)\n",
 738                          rc, rc, rc);
 739         return rc;
 740 }
 741 EXPORT_SYMBOL(libcfs_log_return);
 742
 743 void libcfs_log_goto(struct libcfs_debug_msg_data *msgdata, const char *label,
 744                      long rc)
 745 {
 746         libcfs_debug_msg(msgdata, "Process leaving via %s (rc=%lu : %ld"
 747                          " : %#lx)\n", label, rc, rc, rc);
 748 }
 749 EXPORT_SYMBOL(libcfs_log_goto);