Re: [xml] Deadlock in catalog.c?

[Daniel Veillard <veillard redhat com>]

On Fri, Feb 11, 2011 at 12:42:42PM +0100, Mark Van Peteghem wrote:
> Hi,
>
> I'm stuck on what looks like a deadlock in libxml2.
>
> My application calls xmlInitializeCatalog() and xmlLoadCatalog(...)
> (which returns 0) in the main thread. Then another thread is
> launched in which I do XML validation with DTDs. These work fine
> until a XML file refers to a DTD that has to be looked up in the
> catalog file that I loaded with xmlLoadCatalog(...): then the thread
> blocks when trying to lock xmlCatalogMutex (catalog.c, line 1416 in
> the function xmlFetchXMLCatalogFile). The strange thing is that
> there are no other threads doing any locking (except for the thread
> created by libxml2 that waits in xmlGlobalStateCleanupHelper).
>
> I noticed that if I do the same XML validation on the main thread,
> it works fine, and after that it works on the other thread as well.

  Provide a self contained example showing the problem.
If you look at the source code there is a program testThreads.c
which do exercise threading and catalogs in a concurrent way.
Also make 100% sure you did call xmlInitParser() in the main thread
prior to any multithreaded operations, c.f. the documentation:

  http://xmlsoft.org/threads.html

Daniel

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