src/sthread/ObjectAccess.cpp

   1 /* Copyright (c) 2002-2023. The SimGrid Team. All rights reserved.          */
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the license (GNU LGPL) which comes with this package. */
   5
   6 /* Object access checker, for use in sthread. */
   7
   8 #include "simgrid/modelchecker.h"
   9 #include "simgrid/s4u/Actor.hpp"
  10 #include "simgrid/simix.hpp"
  11 #include "src/kernel/actor/ActorImpl.hpp"
  12 #include "src/kernel/actor/SimcallObserver.hpp"
  13 #include "src/sthread/sthread.h"
  14 #include "xbt/string.hpp"
  15
  16 #include <unordered_map>
  17
  18 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(sthread);
  19
  20 namespace simgrid::sthread {
  21 XBT_DECLARE_ENUM_CLASS(AccessType, ENTER, EXIT, BOTH);
  22
  23 class ObjectAccessObserver final : public simgrid::kernel::actor::SimcallObserver {
  24   AccessType type_;
  25   void* objaddr_;
  26   const char* objname_;
  27   const char* file_;
  28   int line_;
  29
  30 public:
  31   ObjectAccessObserver(simgrid::kernel::actor::ActorImpl* actor, AccessType type, void* objaddr, const char* objname,
  32                        const char* file, int line)
  33       : SimcallObserver(actor), type_(type), objaddr_(objaddr), objname_(objname), file_(file), line_(line)
  34   {
  35   }
  36   void serialize(std::stringstream& stream) const override;
  37   std::string to_string() const override;
  38 };
  39 void ObjectAccessObserver::serialize(std::stringstream& stream) const
  40 {
  41   stream << (short)mc::Transition::Type::OBJECT_ACCESS << ' ';
  42   stream << (short)type_ << ' ' << objaddr_ << ' ' << objname_ << ' ' << file_ << ' ' << line_;
  43 }
  44 std::string ObjectAccessObserver::to_string() const
  45 {
  46   return std::string("AccessObject(") + objname_ + ")";
  47 }
  48 }; // namespace simgrid::sthread
  49
  50 struct ObjectOwner {
  51   simgrid::kernel::actor::ActorImpl* owner = nullptr;
  52   const char* file                         = nullptr;
  53   int line                                 = -1;
  54   int recursive_depth                      = 0;
  55   explicit ObjectOwner(simgrid::kernel::actor::ActorImpl* o) : owner(o) {}
  56 };
  57
  58 std::unordered_map<void*, ObjectOwner*> owners;
  59 static void clean_owners()
  60 {
  61   for (auto it = owners.begin(); it != owners.end();) {
  62     delete it->second;
  63     it = owners.erase(it);
  64   }
  65 }
  66 static ObjectOwner* get_owner(void* object)
  67 {
  68   if (owners.empty())
  69     std::atexit(clean_owners);
  70   if (auto it = owners.find(object); it != owners.end())
  71     return it->second;
  72   auto* o = new ObjectOwner(nullptr);
  73   owners.emplace(object, o);
  74   return o;
  75 }
  76
  77 int sthread_access_begin(void* objaddr, const char* objname, const char* file, int line, const char* func)
  78 {
  79   sthread_disable();
  80   auto* self = simgrid::kernel::actor::ActorImpl::self();
  81   simgrid::sthread::ObjectAccessObserver observer(self, simgrid::sthread::AccessType::ENTER, objaddr, objname, file,
  82                                                   line);
  83   bool success = simgrid::kernel::actor::simcall_answered(
  84       [self, objaddr, objname, file, line]() -> bool {
  85         XBT_INFO("%s takes %s", self->get_cname(), objname);
  86         auto* ownership = get_owner(objaddr);
  87         if (ownership->owner == self) {
  88           ownership->recursive_depth++;
  89           return true;
  90         } else if (ownership->owner != nullptr) {
  91           auto msg = std::string("Unprotected concurent access to ") + objname + ": " + ownership->owner->get_name();
  92           if (not xbt_log_no_loc) {
  93             msg += simgrid::xbt::string_printf(" at %s:%d", ownership->file, ownership->line);
  94             if (ownership->recursive_depth > 1) {
  95               msg += simgrid::xbt::string_printf(" (and %d other locations)", ownership->recursive_depth - 1);
  96               if (ownership->recursive_depth != 2)
  97                 msg += "s";
  98             }
  99           } else {
 100             msg += simgrid::xbt::string_printf(" from %d location", ownership->recursive_depth);
 101             if (ownership->recursive_depth != 1)
 102               msg += "s";
 103           }
 104           msg += " vs " + self->get_name();
 105           if (xbt_log_no_loc)
 106             msg += std::string(" (locations hidden because of --log=no_loc).");
 107           else
 108             msg += simgrid::xbt::string_printf(" at %s:%d.", file, line);
 109           XBT_CRITICAL("%s", msg.c_str());
 110           return false;
 111         }
 112         ownership->owner = self;
 113         ownership->file  = file;
 114         ownership->line  = line;
 115         ownership->recursive_depth = 1;
 116         return true;
 117       },
 118       &observer);
 119   MC_assert(success);
 120   xbt_assert(success, "Problem detected, bailing out");
 121   sthread_enable();
 122   return true;
 123 }
 124 void sthread_access_end(void* objaddr, const char* objname, const char* file, int line, const char* func)
 125 {
 126   sthread_disable();
 127   auto* self = simgrid::kernel::actor::ActorImpl::self();
 128   simgrid::sthread::ObjectAccessObserver observer(self, simgrid::sthread::AccessType::EXIT, objaddr, objname, file,
 129                                                   line);
 130   simgrid::kernel::actor::simcall_answered(
 131       [self, objaddr, objname]() -> void {
 132         XBT_INFO("%s releases %s", self->get_cname(), objname);
 133         auto* ownership = get_owner(objaddr);
 134         xbt_assert(ownership->owner == self,
 135                    "safety check failed: %s is not owner of the object it's releasing. That object owned by %s.",
 136                    self->get_cname(), (ownership->owner == nullptr ? "nobody" : ownership->owner->get_cname()));
 137         ownership->recursive_depth--;
 138         if (ownership->recursive_depth == 0)
 139           ownership->owner = nullptr;
 140       },
 141       &observer);
 142   sthread_enable();
 143 }