On Thu, Nov 06, 2008 at 09:58:52PM +0100, Ruediger Pluem wrote:
> What is the problem at all?
>
> mod_proxy_http uses a a conn_rec to communicate with the backend. It somehow
> reverses
> the meaning of input and output filters and uses them to send the request and
> receive
> the response. In order to use persistent SSL connections to the backend it is
> needed
> to keep this conn_rec (and thus its bucket allocator) alive and tied to the
> backend
> connection. Thus it is no longer destroyed at the end of a client request /
> connection.
> So the conn_rec and especially the bucket allocator for the backend have a
> lifecycle
> that is disjoint from the one to the client. Especially it can happen that
> due to e.g.
> a faulty backend connection the conn_rec to the backend *lives* shorter than
> buckets that are still buffered somewhere in the output filter chain to the
> client
> (see comments in removed code below). This causes segfaults when these
> buckets are
> accessed then or if brigades that contain them get cleaned up later on due to
> a parent
> pool cleanup.
Not sure if I've got my head round this correctly, but...
Would it be possible to substitute the backend ("fake") conn_rec's
->bucket_alloc pointer with the "real" r->connection->bucket_alloc, for
the duration of the request/response to the backend? Wouldn't that
ensure that all the buckets in question exactly have the correct
lifetime?
Regards, Joe
