HTTPSessionAcceptor::getController() should return a raw pointer, instead of std::shared_ptr

[rainliu]

The reason why it should return a raw pointer is because: One HTTPSessionController is mapped to one HTTPSession. An HTTPSessionAcceptor manages multiple controllers. It is better to follow the same lifetime management as HQSessionController, which return a raw pointer and let itself do self-destroyed in HQSessionController::detachSession().

Otherwise, in

proxygen/proxygen/lib/http/session/HTTPSessionAcceptor.cpp

Line 71 in 3f8d21f

auto controller = getController();

, controller is created as shared_ptr, but used as raw pointer in

proxygen/proxygen/lib/http/session/HTTPSessionAcceptor.cpp

Line 99 in 3f8d21f

controller.get(),

. Then it is auto-released after HTTPSessionAcceptor::onNewConnection is done.

It will increase a lot of burden on HTTPSessionAcceptor side to maintain a copy of std::shared_ptr to handle each HTTPSessionController's lifetime. Otherwise, without a copy inside HTTPSessionAcceptor, after HTTPSessionAcceptor::onNewConnection is done, HTTPSessionController will be released, then HTTPDownstreamSession will encounter a potential heap-use-after-free issue.

blame commit: ad9fd63

My suggestion is to revert the above commit.