Fix deadlock with new pcfind() class of VEX functions.

Fix deadlock with new pcfind() class of VEX functions.

Fix deadlock with new pcfind() class of VEX functions.

Fix deadlock with new pcfind() class of VEX functions.

Fix deadlock that could occur when evaluating invalid channel references on Object nodes.

Fix deadlock that could occur when evaluating invalid channel references on Object nodes.

Fix deadlock that could occur when evaluating invalid channel references on Object nodes.

Fix deadlock that could occur when evaluating invalid channel references on Object nodes.

Fix deadlock that could occur when evaluating invalid channel references on Object nodes.

Fix false positive deadlock errors when evaluating expressions from multiple threads.

Fix false positive deadlock errors when evaluating expressions from multiple threads.

Fix false positive deadlock errors when evaluating expressions from multiple threads.

Fix false positive deadlock errors when evaluating expressions from multiple threads.

Fix false positive deadlock errors when evaluating expressions from multiple threads.

Eliminate a potential deadlock when VEX code is invoked during the execution of another VEX shader.

Eliminate a potential deadlock when VEX code is invoked during the execution of another VEX shader.

Eliminate a potential deadlock when VEX code is invoked during the execution of another VEX shader.

Eliminate a potential deadlock when VEX code is invoked during the execution of another VEX shader.

Eliminate a potential deadlock when VEX code is invoked during the execution of another VEX shader.

Fixed a deadlock in Houdini which sometimes occured when cooking a multi-threaded VOP network that referenced geometry from other VOP nodes.

Fixed a deadlock in Houdini which sometimes occured when cooking a multi-threaded VOP network that referenced geometry from other VOP nodes.

Fixed a deadlock in Houdini which sometimes occured when cooking a multi-threaded VOP network that referenced geometry from other VOP nodes.

Fixed a deadlock in Houdini which sometimes occured when cooking a multi-threaded VOP network that referenced geometry from other VOP nodes.

Fixed a deadlock in Houdini which sometimes occured when cooking a multi-threaded VOP network that referenced geometry from other VOP nodes.

Fixed a deadlock in Houdini which occured when cooking from HOM a multi-threaded network that needed access to Python. As an example, calling `hou.Node.cook()` on a multi-threaded VOP network that contained VOP nodes with Python parameter expressions.