src/mc/mc_safety.c

   1 /* Copyright (c) 2008-2014. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7 #include "mc_private.h"
   8 #include "mc_record.h"
   9
  10 #include "xbt/mmalloc/mmprivate.h"
  11
  12 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_safety, mc,
  13                                 "Logging specific to MC safety verification ");
  14
  15 xbt_dict_t first_enabled_state;
  16
  17 /**
  18  *  \brief Initialize the DPOR exploration algorithm
  19  */
  20 void MC_pre_modelcheck_safety()
  21 {
  22
  23   int mc_mem_set = (mmalloc_get_current_heap() == mc_heap);
  24
  25   mc_state_t initial_state = NULL;
  26   smx_process_t process;
  27
  28   /* Create the initial state and push it into the exploration stack */
  29   if (!mc_mem_set)
  30     MC_SET_MC_HEAP;
  31
  32   if (_sg_mc_visited > 0)
  33     visited_states =
  34         xbt_dynar_new(sizeof(mc_visited_state_t), visited_state_free_voidp);
  35
  36   if (mc_reduce_kind == e_mc_reduce_dpor)
  37     first_enabled_state = xbt_dict_new_homogeneous(&xbt_free_f);
  38
  39   initial_state = MC_state_new();
  40
  41   MC_SET_STD_HEAP;
  42
  43   XBT_DEBUG("**************************************************");
  44   XBT_DEBUG("Initial state");
  45
  46   /* Wait for requests (schedules processes) */
  47   MC_wait_for_requests();
  48
  49   MC_SET_MC_HEAP;
  50
  51   /* Get an enabled process and insert it in the interleave set of the initial state */
  52   xbt_swag_foreach(process, simix_global->process_list) {
  53     if (MC_process_is_enabled(process)) {
  54       MC_state_interleave_process(initial_state, process);
  55       if (mc_reduce_kind != e_mc_reduce_none)
  56         break;
  57     }
  58   }
  59
  60   xbt_fifo_unshift(mc_stack, initial_state);
  61
  62   if (mc_reduce_kind == e_mc_reduce_dpor) {
  63     /* To ensure the soundness of DPOR, we have to keep a list of
  64        processes which are still enabled at each step of the exploration.
  65        If max depth is reached, we interleave them in the state in which they have
  66        been enabled for the first time. */
  67     xbt_swag_foreach(process, simix_global->process_list) {
  68       if (MC_process_is_enabled(process)) {
  69         char *key = bprintf("%lu", process->pid);
  70         char *data = bprintf("%d", xbt_fifo_size(mc_stack));
  71         xbt_dict_set(first_enabled_state, key, data, NULL);
  72         xbt_free(key);
  73       }
  74     }
  75   }
  76
  77   if (!mc_mem_set)
  78     MC_SET_STD_HEAP;
  79 }
  80
  81
  82 /** \brief Model-check the application using a DFS exploration
  83  *         with DPOR (Dynamic Partial Order Reductions)
  84  */
  85 void MC_modelcheck_safety(void)
  86 {
  87
  88   char *req_str = NULL;
  89   int value;
  90   smx_simcall_t req = NULL, prev_req = NULL;
  91   mc_state_t state = NULL, prev_state = NULL, next_state =
  92       NULL, restored_state = NULL;
  93   smx_process_t process = NULL;
  94   xbt_fifo_item_t item = NULL;
  95   mc_state_t state_test = NULL;
  96   int pos;
  97   mc_visited_state_t visited_state = NULL;
  98   int enabled = 0;
  99
 100   while (xbt_fifo_size(mc_stack) > 0) {
 101
 102     /* Get current state */
 103     state = (mc_state_t)
 104         xbt_fifo_get_item_content(xbt_fifo_get_first_item(mc_stack));
 105
 106     XBT_DEBUG("**************************************************");
 107     XBT_DEBUG
 108         ("Exploration depth=%d (state=%p, num %d)(%u interleave, user_max_depth %d, first_enabled_state size : %d)",
 109          xbt_fifo_size(mc_stack), state, state->num,
 110          MC_state_interleave_size(state), user_max_depth_reached,
 111          xbt_dict_size(first_enabled_state));
 112
 113     /* Update statistics */
 114     mc_stats->visited_states++;
 115
 116     /* If there are processes to interleave and the maximum depth has not been reached
 117        then perform one step of the exploration algorithm */
 118     if (xbt_fifo_size(mc_stack) <= _sg_mc_max_depth && !user_max_depth_reached
 119         && (req = MC_state_get_request(state, &value)) && visited_state == NULL) {
 120
 121       MC_LOG_REQUEST(mc_safety, req, value);
 122
 123       if (dot_output != NULL) {
 124         MC_SET_MC_HEAP;
 125         req_str = MC_request_get_dot_output(req, value);
 126         MC_SET_STD_HEAP;
 127       }
 128
 129       MC_state_set_executed_request(state, req, value);
 130       mc_stats->executed_transitions++;
 131
 132       if (mc_reduce_kind == e_mc_reduce_dpor) {
 133         MC_SET_MC_HEAP;
 134         char *key = bprintf("%lu", req->issuer->pid);
 135         xbt_dict_remove(first_enabled_state, key);
 136         xbt_free(key);
 137         MC_SET_STD_HEAP;
 138       }
 139
 140       /* Answer the request */
 141       SIMIX_simcall_handle(req, value);
 142
 143       /* Wait for requests (schedules processes) */
 144       MC_wait_for_requests();
 145
 146       /* Create the new expanded state */
 147       MC_SET_MC_HEAP;
 148
 149       next_state = MC_state_new();
 150
 151       if ((visited_state = is_visited_state()) == NULL) {
 152
 153         /* Get an enabled process and insert it in the interleave set of the next state */
 154         xbt_swag_foreach(process, simix_global->process_list) {
 155           if (MC_process_is_enabled(process)) {
 156             MC_state_interleave_process(next_state, process);
 157             if (mc_reduce_kind != e_mc_reduce_none)
 158               break;
 159           }
 160         }
 161
 162         if (_sg_mc_checkpoint
 163             && ((xbt_fifo_size(mc_stack) + 1) % _sg_mc_checkpoint == 0)) {
 164           next_state->system_state = MC_take_snapshot(next_state->num);
 165         }
 166
 167         if (dot_output != NULL)
 168           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", state->num,
 169                   next_state->num, req_str);
 170
 171       } else {
 172
 173         if (dot_output != NULL)
 174           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", state->num,
 175                   visited_state->other_num == -1 ? visited_state->num : visited_state->other_num, req_str);
 176
 177       }
 178
 179       xbt_fifo_unshift(mc_stack, next_state);
 180
 181       if (mc_reduce_kind == e_mc_reduce_dpor) {
 182         /* Insert in dict all enabled processes, if not included yet */
 183         xbt_swag_foreach(process, simix_global->process_list) {
 184           if (MC_process_is_enabled(process)) {
 185             char *key = bprintf("%lu", process->pid);
 186             if (xbt_dict_get_or_null(first_enabled_state, key) == NULL) {
 187               char *data = bprintf("%d", xbt_fifo_size(mc_stack));
 188               xbt_dict_set(first_enabled_state, key, data, NULL);
 189             }
 190             xbt_free(key);
 191           }
 192         }
 193       }
 194
 195       if (dot_output != NULL)
 196         xbt_free(req_str);
 197
 198       MC_SET_STD_HEAP;
 199
 200       /* Let's loop again */
 201
 202       /* The interleave set is empty or the maximum depth is reached, let's back-track */
 203     } else {
 204
 205       if ((xbt_fifo_size(mc_stack) > _sg_mc_max_depth) || user_max_depth_reached
 206           || visited_state != NULL) {
 207
 208         if (user_max_depth_reached && visited_state == NULL)
 209           XBT_DEBUG("User max depth reached !");
 210         else if (visited_state == NULL)
 211           XBT_WARN("/!\\ Max depth reached ! /!\\ ");
 212         else
 213           XBT_DEBUG("State already visited (equal to state %d), exploration stopped on this path.", visited_state->other_num == -1 ? visited_state->num : visited_state->other_num);
 214
 215         if (mc_reduce_kind == e_mc_reduce_dpor) {
 216           /* Interleave enabled processes in the state in which they have been enabled for the first time */
 217           xbt_swag_foreach(process, simix_global->process_list) {
 218             if (MC_process_is_enabled(process)) {
 219               char *key = bprintf("%lu", process->pid);
 220               enabled =
 221                   (int) strtoul(xbt_dict_get_or_null(first_enabled_state, key),
 222                                 0, 10);
 223               xbt_free(key);
 224               int cursor = xbt_fifo_size(mc_stack);
 225               xbt_fifo_foreach(mc_stack, item, state_test, mc_state_t) {
 226                 if (cursor-- == enabled) {
 227                   if (!MC_state_process_is_done(state_test, process)
 228                       && state_test->num != state->num) {
 229                     XBT_DEBUG("Interleave process %lu in state %d",
 230                               process->pid, state_test->num);
 231                     MC_state_interleave_process(state_test, process);
 232                     break;
 233                   }
 234                 }
 235               }
 236             }
 237           }
 238         }
 239
 240       } else {
 241
 242         XBT_DEBUG("There are no more processes to interleave. (depth %d)",
 243                   xbt_fifo_size(mc_stack) + 1);
 244
 245       }
 246
 247       MC_SET_MC_HEAP;
 248
 249       /* Trash the current state, no longer needed */
 250       xbt_fifo_shift(mc_stack);
 251       MC_state_delete(state);
 252       XBT_DEBUG("Delete state %d at depth %d", state->num,
 253                 xbt_fifo_size(mc_stack) + 1);
 254
 255       MC_SET_STD_HEAP;
 256
 257       visited_state = NULL;
 258
 259       /* Check for deadlocks */
 260       if (MC_deadlock_check()) {
 261         MC_show_deadlock(NULL);
 262         return;
 263       }
 264
 265       MC_SET_MC_HEAP;
 266       /* Traverse the stack backwards until a state with a non empty interleave
 267          set is found, deleting all the states that have it empty in the way.
 268          For each deleted state, check if the request that has generated it
 269          (from it's predecesor state), depends on any other previous request
 270          executed before it. If it does then add it to the interleave set of the
 271          state that executed that previous request. */
 272
 273       while ((state = xbt_fifo_shift(mc_stack)) != NULL) {
 274         if (mc_reduce_kind == e_mc_reduce_dpor) {
 275           req = MC_state_get_internal_request(state);
 276           xbt_fifo_foreach(mc_stack, item, prev_state, mc_state_t) {
 277             if (MC_request_depend
 278                 (req, MC_state_get_internal_request(prev_state))) {
 279               if (XBT_LOG_ISENABLED(mc_safety, xbt_log_priority_debug)) {
 280                 XBT_DEBUG("Dependent Transitions:");
 281                 prev_req = MC_state_get_executed_request(prev_state, &value);
 282                 req_str = MC_request_to_string(prev_req, value);
 283                 XBT_DEBUG("%s (state=%d)", req_str, prev_state->num);
 284                 xbt_free(req_str);
 285                 prev_req = MC_state_get_executed_request(state, &value);
 286                 req_str = MC_request_to_string(prev_req, value);
 287                 XBT_DEBUG("%s (state=%d)", req_str, state->num);
 288                 xbt_free(req_str);
 289               }
 290
 291               if (!MC_state_process_is_done(prev_state, req->issuer))
 292                 MC_state_interleave_process(prev_state, req->issuer);
 293               else
 294                 XBT_DEBUG("Process %p is in done set", req->issuer);
 295
 296               break;
 297
 298             } else if (req->issuer ==
 299                        MC_state_get_internal_request(prev_state)->issuer) {
 300
 301               XBT_DEBUG("Simcall %d and %d with same issuer", req->call,
 302                         MC_state_get_internal_request(prev_state)->call);
 303               break;
 304
 305             } else {
 306
 307               XBT_DEBUG
 308                   ("Simcall %d, process %lu (state %d) and simcall %d, process %lu (state %d) are independant",
 309                    req->call, req->issuer->pid, state->num,
 310                    MC_state_get_internal_request(prev_state)->call,
 311                    MC_state_get_internal_request(prev_state)->issuer->pid,
 312                    prev_state->num);
 313
 314             }
 315           }
 316         }
 317
 318         if (MC_state_interleave_size(state)
 319             && xbt_fifo_size(mc_stack) < _sg_mc_max_depth) {
 320           /* We found a back-tracking point, let's loop */
 321           XBT_DEBUG("Back-tracking to state %d at depth %d", state->num,
 322                     xbt_fifo_size(mc_stack) + 1);
 323           if (_sg_mc_checkpoint) {
 324             if (state->system_state != NULL) {
 325               MC_restore_snapshot(state->system_state);
 326               xbt_fifo_unshift(mc_stack, state);
 327               MC_SET_STD_HEAP;
 328             } else {
 329               pos = xbt_fifo_size(mc_stack);
 330               item = xbt_fifo_get_first_item(mc_stack);
 331               while (pos > 0) {
 332                 restored_state = (mc_state_t) xbt_fifo_get_item_content(item);
 333                 if (restored_state->system_state != NULL) {
 334                   break;
 335                 } else {
 336                   item = xbt_fifo_get_next_item(item);
 337                   pos--;
 338                 }
 339               }
 340               MC_restore_snapshot(restored_state->system_state);
 341               xbt_fifo_unshift(mc_stack, state);
 342               MC_SET_STD_HEAP;
 343               MC_replay(mc_stack, pos);
 344             }
 345           } else {
 346             xbt_fifo_unshift(mc_stack, state);
 347             MC_SET_STD_HEAP;
 348             MC_replay(mc_stack, -1);
 349           }
 350           XBT_DEBUG("Back-tracking to state %d at depth %d done", state->num,
 351                     xbt_fifo_size(mc_stack));
 352           break;
 353         } else {
 354           XBT_DEBUG("Delete state %d at depth %d", state->num,
 355                     xbt_fifo_size(mc_stack) + 1);
 356           MC_state_delete(state);
 357         }
 358       }
 359       MC_SET_STD_HEAP;
 360     }
 361   }
 362   MC_print_statistics(mc_stats);
 363   MC_SET_STD_HEAP;
 364
 365   return;
 366 }