Re: [xml] Crash/Memory leak in threads.c

["Eugene Gershnik" <gershnik hotmail com>]

Stéphane Bidoul wrote:
> Eugene Gershnik wrote:
>
> > [...]
> >
> >
> > 1. An application creates some threads _before loading libxml_
> > 2. The application loads libxml explicitly and performs some
> > operations from the threads created in step 1.
> > 3. The application unloads libxml. At this point the
> > DLL_PROCESS_DETACH notification _will not be sent_ for the threads
> > that existed prior to libxml loading (i.e. threads from step 1).
> > Result: memory leak.
> I suppose you mean DLL_*THREAD*_DETACH?

Right, I mistyped the name.

> > I belevie that it is impossible to make DLL_PROCESS_DETACH to work
> > correctly. For myself I solved the problem by storing a list of
> > allocated xmlGlobalStates and freeing it on DLL_PROCESS_DETACH. I
> > would gladly post the code if there is an interest in it.
> Sure. However, you must continue to free the xmlGlobalState in
> DLL_THREAD_DETACH also, for (common) situations where libxml is
> loaded
> and then many threads are created and destroyed.

Sure thing. What I did was to link the CleanupParams structures into a
doubly linked list. The DLL_THREAD_DETACH notification continues to clean up
as before and removes an entry from the list. Finally, on DLL_PROCESS_DETACH
I clean up whatever is left in the linked list. This of course requires a
critical section to protect list insertions/deletions but since it is being
used only on initial xmlGlobalState creation and thread cleanup I don't
think it will have any noticable performance impact.


Best Regards,
Eugene