Merge "media log: do not lock mutex in dump()" into nyc-dev (cd7f5924) · Commits · e / os / android_frameworks_av

services/medialog/MediaLogService.cpp

+29 −1

Original line number	Diff line number	Diff line
		@@ -26,6 +26,8 @@

		namespace android {

		static const char kDeadlockedString[] = "MediaLogService may be deadlocked\n";

		void MediaLogService::registerWriter(const sp<IMemory>& shared, size_t size, const char *name)
		{
		if (IPCThreadState::self()->getCallingUid() != AID_AUDIOSERVER \|\| shared == 0 \|\|
		@@ -54,6 +56,19 @@ void MediaLogService::unregisterWriter(const sp<IMemory>& shared)
		}
		}

		bool MediaLogService::dumpTryLock(Mutex& mutex)
		{
		bool locked = false;
		for (int i = 0; i < kDumpLockRetries; ++i) {
		if (mutex.tryLock() == NO_ERROR) {
		locked = true;
		break;
		}
		usleep(kDumpLockSleepUs);
		}
		return locked;
		}

		status_t MediaLogService::dump(int fd, const Vector<String16>& args __unused)
		{
		// FIXME merge with similar but not identical code at services/audioflinger/ServiceUtilities.cpp
		@@ -68,9 +83,22 @@ status_t MediaLogService::dump(int fd, const Vector<String16>& args __unused)

		Vector<NamedReader> namedReaders;
		{
		Mutex::Autolock _l(mLock);
		bool locked = dumpTryLock(mLock);

		// failed to lock - MediaLogService is probably deadlocked
		if (!locked) {
		String8 result(kDeadlockedString);
		if (fd >= 0) {
		write(fd, result.string(), result.size());
		} else {
		ALOGW("%s:", result.string());
		}
		return NO_ERROR;
		}
		namedReaders = mNamedReaders;
		mLock.unlock();
		}

		for (size_t i = 0; i < namedReaders.size(); i++) {
		const NamedReader& namedReader = namedReaders[i];
		if (fd >= 0) {

+6 −0

Original line number	Diff line number	Diff line
		@@ -43,6 +43,12 @@ public:
		uint32_t flags);

		private:

		// Internal dump
		static const int kDumpLockRetries = 50;
		static const int kDumpLockSleepUs = 20000;
		static bool dumpTryLock(Mutex& mutex);

		Mutex mLock;
		class NamedReader {
		public: