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Commit 80d23935 authored by Steven Moreland's avatar Steven Moreland
Browse files

binder: Bp: clear DRs in onLastStrongRef 

This way, if unlink is not called, the binder will properly
destruct. Currently linkToDeath takes a weakRef, and when
BR_DEAD_BINDER is received, userspace binder sends
BC_CLEAR_DEATH_NOTIFICATION for each death notification. Then, when it
receives BR_CLEAR_DEATH_NOTIFICATION_DONE (maybe later?), it clears the
weak ref. Right now, ~BpBinder also clears these. However, by moving
this clearing up to onLastStrongRef, forgotten unlinks will no longer
cause a cycle (that is only cleared when the service dies).

Bug: 134576445
Test: manually linking to death many times without unlinking.
Change-Id: Iaf6ce7a65c334805ae2dc146b9f0aa7731a99c0d
parent 49b166e2

libs/binder/BpBinder.cpp

+19 −15
Original line number Diff line number Diff line
@@ -387,21 +387,6 @@ BpBinder::~BpBinder() 
        }

    }



    mLock.lock();

    Vector<Obituary>* obits = mObituaries;

    if(obits != nullptr) {

        if (ipc) ipc->clearDeathNotification(mHandle, this);

        mObituaries = nullptr;

    }

    mLock.unlock();



    if (obits != nullptr) {

        // XXX Should we tell any remaining DeathRecipient

        // objects that the last strong ref has gone away, so they

        // are no longer linked?

        delete obits;

    }



    if (ipc) {

        ipc->expungeHandle(mHandle, this);

        ipc->decWeakHandle(mHandle);
@@ -423,6 +408,25 @@ void BpBinder::onLastStrongRef(const void* /*id*/) 
    }

    IPCThreadState* ipc = IPCThreadState::self();

    if (ipc) ipc->decStrongHandle(mHandle);



    mLock.lock();

    Vector<Obituary>* obits = mObituaries;

    if(obits != nullptr) {

        if (!obits->isEmpty()) {

            ALOGI("onLastStrongRef automatically unlinking death recipients");

        }



        if (ipc) ipc->clearDeathNotification(mHandle, this);

        mObituaries = nullptr;

    }

    mLock.unlock();



    if (obits != nullptr) {

        // XXX Should we tell any remaining DeathRecipient

        // objects that the last strong ref has gone away, so they

        // are no longer linked?

        delete obits;

    }

}



bool BpBinder::onIncStrongAttempted(uint32_t /*flags*/, const void* /*id*/)