Re: [PATCH] Fix locking-related segfaults and deadlocks in the SWIG Python bindings

On 10/18/05, Marc Haesen <Marc.Haesen@telindus.be> wrote:
> > This patch should fix the segfaults reported by Marc Haesen and Max
> > Bowsher when using the Python bindings with ViewCVS in mod_python
> > mode. I haven't tested this patch with mod_python yet, so please let
> > me know if it helps.
> >
> > If you are using Python 2.3, this patch additionally solves a
> > theoretical deadlock bug in the Python bindings where the bindings
> > could hang if the same thread tried to acquire the global interpreter
> > lock recursively.
> >
> > For more information on the Python threading APIs, see:
> > http://www.etsimo.uniovi.es/python/dev/doc/devel/api/threads.html
> >
> > [[[
> >
> > Fix locking-related segfaults in the Python bindings. If you are using
> > Python
> > 2.3, this patch additionally solves a theoretical deadlock bug in the
> > Python
> > bindings where the bindings could hang if the same thread tried to
> > acquire the
> > global interpreter lock recursively.
> >
> > * subversion/bindings/swig/include/svn_types.swg
> > (exception): Use Py_BEGIN_ALLOW_THREADS instead of
> > svn_swig_py_release_py_lock. Use Py_END_ALLOW_THREADS instead of
> > svn_swig_py_acquire_py_lock.
> >
> > * subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.h
> > (svn_swig_py_release_py_lock, svn_swig_py_acquire_py_lock): Remove.
> >
> > * subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c
> > (SVN_SWIG_PY_BEGIN_PYTHON_CALL, SVN_SWIG_PY_END_PYTHON_CALL):
> > New.
> > (svn_swig_py_release_py_lock, svn_swig_py_acquire_py_lock,
> > _saved_thread_key, _saved_thread_pool): Remove.
> > (threads_terminated): New variable.
> > (svn_swig_py__terminate): New.
> > (svn_swig_py_initialize): Initialize Python and threads. Use
> > svn_swig_py__terminate in place of apr_terminate.
> >
> > (svn_swig_py_pool_destroyed, svn_swig_py_pool_decref,
> > svn_swig_py_register_cleanup, close_baton, set_target_revision,
> > open_root, delete_entry, add_directory, open_directory,
> > change_dir_prop, close_directory, add_file, open_file,
> > window_handler, apply_textdelta, change_file_prop, close_file,
> > read_handler_pyio, write_handler_pyio, svn_swig_py_notify_func,
> > svn_swig_py_status_func, svn_swig_py_cancel_func,
> > svn_swig_py_fs_get_locks_func, svn_swig_py_get_commit_log_func,
> > svn_swig_py_repos_authz_func, svn_swig_py_repos_history_func,
> > svn_swig_py_log_receiver, svn_swig_py_client_blame_receiver,
> > svn_swig_py_auth_simple_prompt_func,
> > svn_swig_py_username_prompt_func,
> > svn_swig_py_auth_ssl_server_trust_prompt_func,
> > svn_swig_py_auth_ssl_client_cert_prompt_func,
> > svn_swig_py_auth_ssl_client_cert_pw_prompt_func):
> > Use SVN_SWIG_PY_BEGIN_PYTHON_CALL instead of
> > svn_swig_py_acquire_py_lock.
> > Use SVN_SWIG_PY_END_PYTHON_CALL instead of
> > svn_swig_py_release_py_lock.
> If I apply this patch apache (with mod_python and python 2.4.2) is
> crashing randomly (not only at shutdown/restart).
Thanks for testing this, Marc! It looks like we'll need to look into
this more closely then, since I don't have a debug setup for
mod_python. Max?

Cheers,

David

--
David James -- http://www.cs.toronto.edu/~james