/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "sles_allinclusive.h" // Use this macro to validate a pthread_t before passing it into pthread_gettid_np. // One of the common reasons for deadlock is trying to lock a mutex for an object // which has been destroyed (which does memset to 0x00 or 0x55 as the final step). // To avoid crashing with a SIGSEGV right before we're about to log a deadlock warning, // we check that the pthread_t is probably valid. Note that it is theoretically // possible for something to look like a valid pthread_t but not actually be valid. // So we might still crash, but only in the case where a deadlock was imminent anyway. #define LIKELY_VALID(ptr) (((ptr) != (pthread_t) 0) && ((((size_t) (ptr)) & 3) == 0)) /** \brief Exclusively lock an object */ #ifdef USE_DEBUG void init_time_spec(timespec* ts, long delta) { clock_gettime(CLOCK_REALTIME, ts); ts->tv_nsec += delta; if (ts->tv_nsec >= 1000000000L) { ts->tv_sec++; ts->tv_nsec -= 1000000000L; } } void object_lock_exclusive_(IObject *thiz, const char *file, int line) { int ok; ok = pthread_mutex_trylock(&thiz->mMutex); if (0 != ok) { // not android_atomic_acquire_load because we don't care about relative load/load ordering int32_t oldGeneration = thiz->mGeneration; // wait up to a total of 250 ms static const long nanoBackoffs[] = { 10 * 1000000, 20 * 1000000, 30 * 1000000, 40 * 1000000, 50 * 1000000, 100 * 1000000}; unsigned i = 0; timespec ts; memset(&ts, 0, sizeof(timespec)); for (;;) { init_time_spec(&ts, nanoBackoffs[i]); ok = pthread_mutex_timedlock(&thiz->mMutex, &ts); if (0 == ok) { break; } if (EBUSY == ok) { // this is the expected return value for timeout, and will be handled below } else if (EDEADLK == ok) { // we don't use the kind of mutex that can return this error, but just in case SL_LOGE("%s:%d: recursive lock detected", file, line); } else { // some other return value SL_LOGE("%s:%d: pthread_mutex_lock_timeout_np returned %d", file, line, ok); } // is anyone else making forward progress? int32_t newGeneration = thiz->mGeneration; if (newGeneration != oldGeneration) { // if we ever see forward progress then lock without timeout (more efficient) goto forward_progress; } // no, then continue trying to lock but with increasing timeouts if (++i >= (sizeof(nanoBackoffs) / sizeof(nanoBackoffs[0]))) { // the extra block avoids a C++ compiler error about goto past initialization { pthread_t me = pthread_self(); pthread_t owner = thiz->mOwner; // unlikely, but this could result in a memory fault if owner is corrupt pid_t ownerTid = LIKELY_VALID(owner) ? pthread_gettid_np(owner) : -1; SL_LOGW("%s:%d: pthread %p (tid %d) sees object %p was locked by pthread %p" " (tid %d) at %s:%d\n", file, line, *(void **)&me, gettid(), thiz, *(void **)&owner, ownerTid, thiz->mFile, thiz->mLine); } forward_progress: // attempt one more time without timeout; maybe this time we will be successful ok = pthread_mutex_lock(&thiz->mMutex); assert(0 == ok); break; } } } // here if mutex was successfully locked pthread_t zero; memset(&zero, 0, sizeof(pthread_t)); if (0 != memcmp(&zero, &thiz->mOwner, sizeof(pthread_t))) { pthread_t me = pthread_self(); pthread_t owner = thiz->mOwner; pid_t ownerTid = LIKELY_VALID(owner) ? pthread_gettid_np(owner) : -1; if (pthread_equal(pthread_self(), owner)) { SL_LOGE("%s:%d: pthread %p (tid %d) sees object %p was recursively locked by pthread" " %p (tid %d) at %s:%d\n", file, line, *(void **)&me, gettid(), thiz, *(void **)&owner, ownerTid, thiz->mFile, thiz->mLine); } else { SL_LOGE("%s:%d: pthread %p (tid %d) sees object %p was left unlocked in unexpected" " state by pthread %p (tid %d) at %s:%d\n", file, line, *(void **)&me, gettid(), thiz, *(void **)&owner, ownerTid, thiz->mFile, thiz->mLine); } assert(false); } thiz->mOwner = pthread_self(); thiz->mFile = file; thiz->mLine = line; // not android_atomic_inc because we are already holding a mutex ++thiz->mGeneration; } #else void object_lock_exclusive(IObject *thiz) { int ok; ok = pthread_mutex_lock(&thiz->mMutex); assert(0 == ok); } #endif /** \brief Exclusively unlock an object and do not report any updates */ #ifdef USE_DEBUG void object_unlock_exclusive_(IObject *thiz, const char *file, int line) { assert(pthread_equal(pthread_self(), thiz->mOwner)); assert(NULL != thiz->mFile); assert(0 != thiz->mLine); memset(&thiz->mOwner, 0, sizeof(pthread_t)); thiz->mFile = file; thiz->mLine = line; int ok; ok = pthread_mutex_unlock(&thiz->mMutex); assert(0 == ok); } #else void object_unlock_exclusive(IObject *thiz) { int ok; ok = pthread_mutex_unlock(&thiz->mMutex); assert(0 == ok); } #endif /** \brief Exclusively unlock an object and report updates to the specified bit-mask of * attributes */ #ifdef USE_DEBUG void object_unlock_exclusive_attributes_(IObject *thiz, unsigned attributes, const char *file, int line) #else void object_unlock_exclusive_attributes(IObject *thiz, unsigned attributes) #endif { #ifdef USE_DEBUG assert(pthread_equal(pthread_self(), thiz->mOwner)); assert(NULL != thiz->mFile); assert(0 != thiz->mLine); #endif int ok; // make SL object IDs be contiguous with XA object IDs SLuint32 objectID = IObjectToObjectID(thiz); SLuint32 index = objectID; if ((XA_OBJECTID_ENGINE <= index) && (index <= XA_OBJECTID_CAMERADEVICE)) { ; } else if ((SL_OBJECTID_ENGINE <= index) && (index <= SL_OBJECTID_METADATAEXTRACTOR)) { index -= SL_OBJECTID_ENGINE - XA_OBJECTID_CAMERADEVICE - 1; } else { assert(false); index = 0; } // first synchronously handle updates to attributes here, while object is still locked. // This appears to be a loop, but actually typically runs through the loop only once. unsigned asynchronous = attributes; while (attributes) { // this sequence is carefully crafted to be O(1); tread carefully when making changes unsigned bit = ctz(attributes); // ATTR_INDEX_MAX == next bit position after the last attribute assert(ATTR_INDEX_MAX > bit); // compute the entry in the handler table using object ID and bit number AttributeHandler handler = handlerTable[index][bit]; if (NULL != handler) { asynchronous &= ~(*handler)(thiz); } attributes &= ~(1 << bit); } // any remaining attributes are handled asynchronously in the sync thread if (asynchronous) { unsigned oldAttributesMask = thiz->mAttributesMask; thiz->mAttributesMask = oldAttributesMask | asynchronous; if (oldAttributesMask) { asynchronous = ATTR_NONE; } } #ifdef ANDROID // FIXME hack to safely handle a post-unlock PrefetchStatus callback and/or AudioTrack::start() slPrefetchCallback prefetchCallback = NULL; void *prefetchContext = NULL; SLuint32 prefetchEvents = SL_PREFETCHEVENT_NONE; android::sp audioTrack; if (SL_OBJECTID_AUDIOPLAYER == objectID) { CAudioPlayer *ap = (CAudioPlayer *) thiz; prefetchCallback = ap->mPrefetchStatus.mDeferredPrefetchCallback; prefetchContext = ap->mPrefetchStatus.mDeferredPrefetchContext; prefetchEvents = ap->mPrefetchStatus.mDeferredPrefetchEvents; ap->mPrefetchStatus.mDeferredPrefetchCallback = NULL; // clearing these next two fields is not required, but avoids stale data during debugging ap->mPrefetchStatus.mDeferredPrefetchContext = NULL; ap->mPrefetchStatus.mDeferredPrefetchEvents = SL_PREFETCHEVENT_NONE; if (ap->mDeferredStart) { audioTrack = ap->mAudioTrack; ap->mDeferredStart = false; } } #endif #ifdef USE_DEBUG memset(&thiz->mOwner, 0, sizeof(pthread_t)); thiz->mFile = file; thiz->mLine = line; #endif ok = pthread_mutex_unlock(&thiz->mMutex); assert(0 == ok); #ifdef ANDROID // FIXME call the prefetch status callback while not holding the mutex on AudioPlayer if (NULL != prefetchCallback) { // note these are synchronous by the application's thread as it is about to return from API assert(prefetchEvents != SL_PREFETCHEVENT_NONE); CAudioPlayer *ap = (CAudioPlayer *) thiz; // spec requires separate callbacks for each event if (SL_PREFETCHEVENT_STATUSCHANGE & prefetchEvents) { (*prefetchCallback)(&ap->mPrefetchStatus.mItf, prefetchContext, SL_PREFETCHEVENT_STATUSCHANGE); } if (SL_PREFETCHEVENT_FILLLEVELCHANGE & prefetchEvents) { (*prefetchCallback)(&ap->mPrefetchStatus.mItf, prefetchContext, SL_PREFETCHEVENT_FILLLEVELCHANGE); } } // call AudioTrack::start() while not holding the mutex on AudioPlayer if (audioTrack != 0) { audioTrack->start(); audioTrack.clear(); } #endif // first update to this interface since previous sync if (ATTR_NONE != asynchronous) { unsigned id = thiz->mInstanceID; if (0 != id) { --id; assert(MAX_INSTANCE > id); IEngine *thisEngine = &thiz->mEngine->mEngine; // FIXME atomic or here interface_lock_exclusive(thisEngine); thisEngine->mChangedMask |= 1 << id; interface_unlock_exclusive(thisEngine); } } } /** \brief Wait on the condition variable associated with the object; see pthread_cond_wait */ #ifdef USE_DEBUG void object_cond_wait_(IObject *thiz, const char *file, int line) { // note that this will unlock the mutex, so we have to clear the owner assert(pthread_equal(pthread_self(), thiz->mOwner)); assert(NULL != thiz->mFile); assert(0 != thiz->mLine); memset(&thiz->mOwner, 0, sizeof(pthread_t)); thiz->mFile = file; thiz->mLine = line; // alas we don't know the new owner's identity int ok; ok = pthread_cond_wait(&thiz->mCond, &thiz->mMutex); assert(0 == ok); // restore my ownership thiz->mOwner = pthread_self(); thiz->mFile = file; thiz->mLine = line; } #else void object_cond_wait(IObject *thiz) { int ok; ok = pthread_cond_wait(&thiz->mCond, &thiz->mMutex); assert(0 == ok); } #endif /** \brief Signal the condition variable associated with the object; see pthread_cond_signal */ void object_cond_signal(IObject *thiz) { int ok; ok = pthread_cond_signal(&thiz->mCond); assert(0 == ok); } /** \brief Broadcast the condition variable associated with the object; * see pthread_cond_broadcast */ void object_cond_broadcast(IObject *thiz) { int ok; ok = pthread_cond_broadcast(&thiz->mCond); assert(0 == ok); }