drd/drd_cond.c

   1 /*
   2   This file is part of drd, a thread error detector.
   3
   4   Copyright (C) 2006-2017 Bart Van Assche <bvanassche@acm.org>.
   5
   6   This program is free software; you can redistribute it and/or
   7   modify it under the terms of the GNU General Public License as
   8   published by the Free Software Foundation; either version 2 of the
   9   License, or (at your option) any later version.
  10
  11   This program is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19   02111-1307, USA.
  20
  21   The GNU General Public License is contained in the file COPYING.
  22 */
  23
  24
  25 #include "drd_clientobj.h"
  26 #include "drd_cond.h"
  27 #include "drd_error.h"
  28 #include "drd_mutex.h"
  29 #include "pub_tool_errormgr.h"    /* VG_(maybe_record_error)() */
  30 #include "pub_tool_libcassert.h"  /* tl_assert()               */
  31 #include "pub_tool_libcbase.h"    /* VG_(memcmp)()             */
  32 #include "pub_tool_libcprint.h"   /* VG_(printf)()             */
  33 #include "pub_tool_machine.h"     /* VG_(get_IP)()             */
  34 #include "pub_tool_threadstate.h" /* VG_(get_running_tid)()    */
  35
  36
  37 /* Local functions. */
  38
  39 static void DRD_(cond_cleanup)(struct cond_info* p);
  40
  41
  42 /* Local variables. */
  43
  44 static Bool DRD_(s_report_signal_unlocked) = True;
  45 static Bool DRD_(s_trace_cond);
  46
  47
  48 /* Function definitions. */
  49
  50 void DRD_(cond_set_report_signal_unlocked)(const Bool r)
  51 {
  52    DRD_(s_report_signal_unlocked) = r;
  53 }
  54
  55 void DRD_(cond_set_trace)(const Bool trace_cond)
  56 {
  57    DRD_(s_trace_cond) = trace_cond;
  58 }
  59
  60 static
  61 void DRD_(cond_initialize)(struct cond_info* const p, const Addr cond)
  62 {
  63    tl_assert(cond != 0);
  64    tl_assert(p->a1   == cond);
  65    tl_assert(p->type == ClientCondvar);
  66
  67    p->cleanup       = (void(*)(DrdClientobj*))(DRD_(cond_cleanup));
  68    p->delete_thread = 0;
  69    p->waiter_count  = 0;
  70    p->mutex         = 0;
  71 }
  72
  73 /**
  74  * Free the memory that was allocated by cond_initialize(). Called by
  75  * DRD_(clientobj_remove)().
  76  */
  77 static void DRD_(cond_cleanup)(struct cond_info* p)
  78 {
  79    tl_assert(p);
  80    if (p->mutex)
  81    {
  82       struct mutex_info* q;
  83       q = &(DRD_(clientobj_get)(p->mutex, ClientMutex)->mutex);
  84       {
  85          CondDestrErrInfo cde = {
  86             DRD_(thread_get_running_tid)(),
  87             p->a1,
  88             q ? q->a1 : 0,
  89             q ? q->owner : DRD_INVALID_THREADID
  90          };
  91          VG_(maybe_record_error)(VG_(get_running_tid)(),
  92                                  CondDestrErr,
  93                                  VG_(get_IP)(VG_(get_running_tid)()),
  94                                  "Destroying condition variable that is being"
  95                                  " waited upon",
  96                                  &cde);
  97       }
  98    }
  99 }
 100
 101 /**
 102  * Report that the synchronization object at address 'addr' is of the
 103  * wrong type.
 104  */
 105 static void wrong_type(const Addr addr)
 106 {
 107    GenericErrInfo gei = {
 108       .tid  = DRD_(thread_get_running_tid)(),
 109       .addr = addr,
 110    };
 111    VG_(maybe_record_error)(VG_(get_running_tid)(),
 112                            GenericErr,
 113                            VG_(get_IP)(VG_(get_running_tid)()),
 114                            "wrong type of synchronization object",
 115                            &gei);
 116 }
 117
 118 static struct cond_info* cond_get_or_allocate(const Addr cond)
 119 {
 120    struct cond_info *p;
 121
 122    tl_assert(offsetof(DrdClientobj, cond) == 0);
 123    p = &(DRD_(clientobj_get)(cond, ClientCondvar)->cond);
 124    if (p)
 125       return p;
 126
 127    if (DRD_(clientobj_present)(cond, cond + 1))
 128    {
 129       wrong_type(cond);
 130       return 0;
 131    }
 132
 133    p = &(DRD_(clientobj_add)(cond, ClientCondvar)->cond);
 134    DRD_(cond_initialize)(p, cond);
 135    return p;
 136 }
 137
 138 struct cond_info* DRD_(cond_get)(const Addr cond)
 139 {
 140    tl_assert(offsetof(DrdClientobj, cond) == 0);
 141    return &(DRD_(clientobj_get)(cond, ClientCondvar)->cond);
 142 }
 143
 144 /** Called before pthread_cond_init(). */
 145 void DRD_(cond_pre_init)(const Addr cond)
 146 {
 147    struct cond_info* p;
 148
 149    if (DRD_(s_trace_cond))
 150       DRD_(trace_msg)("[%u] cond_init       cond 0x%lx",
 151                       DRD_(thread_get_running_tid)(), cond);
 152
 153    p = DRD_(cond_get)(cond);
 154
 155    if (p) {
 156       CondErrInfo cei = { .tid = DRD_(thread_get_running_tid)(), .cond = cond };
 157       VG_(maybe_record_error)(VG_(get_running_tid)(),
 158                               CondErr,
 159                               VG_(get_IP)(VG_(get_running_tid)()),
 160                               "initialized twice",
 161                               &cei);
 162    }
 163
 164    cond_get_or_allocate(cond);
 165 }
 166
 167 /** Called after pthread_cond_destroy(). */
 168 void DRD_(cond_post_destroy)(const Addr cond, const Bool destroy_succeeded)
 169 {
 170    struct cond_info* p;
 171
 172    if (DRD_(s_trace_cond))
 173       DRD_(trace_msg)("[%u] cond_destroy    cond 0x%lx",
 174                       DRD_(thread_get_running_tid)(), cond);
 175
 176    p = DRD_(cond_get)(cond);
 177    if (p == 0)
 178    {
 179       CondErrInfo cei = { .tid = DRD_(thread_get_running_tid)(), .cond = cond };
 180       VG_(maybe_record_error)(VG_(get_running_tid)(),
 181                               CondErr,
 182                               VG_(get_IP)(VG_(get_running_tid)()),
 183                               "not a condition variable",
 184                               &cei);
 185       return;
 186    }
 187
 188    if (p->waiter_count != 0)
 189    {
 190       CondErrInfo cei = { .tid = DRD_(thread_get_running_tid)(), .cond = cond };
 191       VG_(maybe_record_error)(VG_(get_running_tid)(),
 192                               CondErr,
 193                               VG_(get_IP)(VG_(get_running_tid)()),
 194                               "destruction of condition variable being waited"
 195                               " upon",
 196                               &cei);
 197    }
 198
 199    if (destroy_succeeded)
 200       DRD_(clientobj_remove)(p->a1, ClientCondvar);
 201 }
 202
 203 /**
 204  * Called before pthread_cond_wait(). Note: before this function is called,
 205  * mutex_unlock() has already been called from drd_clientreq.c.
 206  */
 207 void DRD_(cond_pre_wait)(const Addr cond, const Addr mutex)
 208 {
 209    struct cond_info* p;
 210    struct mutex_info* q;
 211
 212    if (DRD_(s_trace_cond))
 213       DRD_(trace_msg)("[%u] cond_pre_wait   cond 0x%lx",
 214                       DRD_(thread_get_running_tid)(), cond);
 215
 216    p = cond_get_or_allocate(cond);
 217    if (!p)
 218    {
 219       CondErrInfo cei = { .tid = DRD_(thread_get_running_tid)(), .cond = cond };
 220       VG_(maybe_record_error)(VG_(get_running_tid)(),
 221                               CondErr,
 222                               VG_(get_IP)(VG_(get_running_tid)()),
 223                               "not a condition variable",
 224                               &cei);
 225       return;
 226    }
 227
 228    if (p->waiter_count == 0)
 229    {
 230       p->mutex = mutex;
 231    }
 232    else if (p->mutex != mutex)
 233    {
 234       CondWaitErrInfo cwei
 235          = { .tid = DRD_(thread_get_running_tid)(),
 236              .cond = cond, .mutex1 = p->mutex, .mutex2 = mutex };
 237       VG_(maybe_record_error)(VG_(get_running_tid)(),
 238                               CondWaitErr,
 239                               VG_(get_IP)(VG_(get_running_tid)()),
 240                               "Inconsistent association of condition variable"
 241                               " and mutex",
 242                               &cwei);
 243    }
 244    tl_assert(p->mutex);
 245    q = DRD_(mutex_get)(p->mutex);
 246    if (q
 247        && q->owner == DRD_(thread_get_running_tid)() && q->recursion_count > 0)
 248    {
 249       const ThreadId vg_tid = VG_(get_running_tid)();
 250       MutexErrInfo MEI = { DRD_(thread_get_running_tid)(),
 251                            q->a1, q->recursion_count, q->owner };
 252       VG_(maybe_record_error)(vg_tid,
 253                               MutexErr,
 254                               VG_(get_IP)(vg_tid),
 255                               "Mutex locked recursively",
 256                               &MEI);
 257    }
 258    else if (q == 0)
 259    {
 260       DRD_(not_a_mutex)(p->mutex);
 261    }
 262
 263    ++p->waiter_count;
 264 }
 265
 266 /**
 267  * Called after pthread_cond_wait().
 268  */
 269 void DRD_(cond_post_wait)(const Addr cond)
 270 {
 271    struct cond_info* p;
 272
 273    if (DRD_(s_trace_cond))
 274       DRD_(trace_msg)("[%u] cond_post_wait  cond 0x%lx",
 275                       DRD_(thread_get_running_tid)(), cond);
 276
 277    p = DRD_(cond_get)(cond);
 278    if (!p)
 279    {
 280       CondDestrErrInfo cde = {
 281          DRD_(thread_get_running_tid)(), cond, 0, DRD_INVALID_THREADID
 282       };
 283       VG_(maybe_record_error)(VG_(get_running_tid)(),
 284                               CondDestrErr,
 285                               VG_(get_IP)(VG_(get_running_tid)()),
 286                               "condition variable has been destroyed while"
 287                               " being waited upon",
 288                               &cde);
 289       return;
 290    }
 291
 292    if (p->waiter_count > 0)
 293    {
 294       --p->waiter_count;
 295       if (p->waiter_count == 0)
 296       {
 297          p->mutex = 0;
 298       }
 299    }
 300 }
 301
 302 static void cond_signal(const DrdThreadId tid, struct cond_info* const cond_p)
 303 {
 304    const ThreadId vg_tid = VG_(get_running_tid)();
 305    const DrdThreadId drd_tid = DRD_(VgThreadIdToDrdThreadId)(vg_tid);
 306
 307    tl_assert(cond_p);
 308
 309    if (cond_p->waiter_count > 0)
 310    {
 311       if (DRD_(s_report_signal_unlocked)
 312           && ! DRD_(mutex_is_locked_by)(cond_p->mutex, drd_tid))
 313       {
 314          /*
 315           * A signal is sent while the associated mutex has not been locked.
 316           * This can indicate but is not necessarily a race condition.
 317           */
 318          CondRaceErrInfo cei = { .tid = DRD_(thread_get_running_tid)(),
 319                                  .cond  = cond_p->a1,
 320                                  .mutex = cond_p->mutex,
 321          };
 322          VG_(maybe_record_error)(vg_tid,
 323                                  CondRaceErr,
 324                                  VG_(get_IP)(vg_tid),
 325                                  "CondErr",
 326                                  &cei);
 327       }
 328    }
 329    else
 330    {
 331       /*
 332        * No other thread is waiting for the signal, hence the signal will
 333        * be lost. This is normal in a POSIX threads application.
 334        */
 335    }
 336 }
 337
 338 static void not_initialized(Addr const cond)
 339 {
 340    CondErrInfo cei = { .tid = DRD_(thread_get_running_tid)(), .cond = cond };
 341    VG_(maybe_record_error)(VG_(get_running_tid)(),
 342                            CondErr,
 343                            VG_(get_IP)(VG_(get_running_tid)()),
 344                            "condition variable has not been initialized",
 345                            &cei);
 346 }
 347
 348 /** Called before pthread_cond_signal(). */
 349 void DRD_(cond_pre_signal)(Addr const cond)
 350 {
 351    struct cond_info* p;
 352
 353    p = DRD_(cond_get)(cond);
 354    if (DRD_(s_trace_cond))
 355       DRD_(trace_msg)("[%u] cond_signal     cond 0x%lx",
 356                       DRD_(thread_get_running_tid)(), cond);
 357
 358    tl_assert(DRD_(pthread_cond_initializer));
 359    if (!p && VG_(memcmp)((void*)cond, (void*)DRD_(pthread_cond_initializer),
 360                          DRD_(pthread_cond_initializer_size)) != 0)
 361    {
 362       not_initialized(cond);
 363       return;
 364    }
 365
 366    if (!p)
 367       p = cond_get_or_allocate(cond);
 368
 369    cond_signal(DRD_(thread_get_running_tid)(), p);
 370 }
 371
 372 /** Called before pthread_cond_broadcast(). */
 373 void DRD_(cond_pre_broadcast)(Addr const cond)
 374 {
 375    struct cond_info* p;
 376
 377    if (DRD_(s_trace_cond))
 378       DRD_(trace_msg)("[%u] cond_broadcast  cond 0x%lx",
 379                       DRD_(thread_get_running_tid)(), cond);
 380
 381    p = DRD_(cond_get)(cond);
 382    tl_assert(DRD_(pthread_cond_initializer));
 383    if (!p && VG_(memcmp)((void*)cond, (void*)DRD_(pthread_cond_initializer),
 384                          DRD_(pthread_cond_initializer_size)) != 0)
 385    {
 386       not_initialized(cond);
 387       return;
 388    }
 389
 390    if (!p)
 391       p = cond_get_or_allocate(cond);
 392
 393    cond_signal(DRD_(thread_get_running_tid)(), p);
 394 }