to opcache filecache. Usually, when a class is being loaded, a dependency
tracking is performed after the call to zend_file_cache_script_store.
But sometimes, when opcache cache is empty and there are many simultaneous
outstanding requests for compilation, some classes do have their
inheritance_cache initialized before the call to zend_file_cache_script_store,
and in that case this pointer is serialized as-is. And when such a class
is loaded from opcache filecache this pointer also loaded as-is, and now
it points to some random location in memory. This causes segfaults occuring
when traversing inheritance_cache of such classes.
We need to reset inheritance_cache pointer of zend_class_entry
upon serialization. This should have been done anyway since it is a sensible
strategy to sanitize any memory pointer upon serialization (either by calling
SERIALIZE_x macros or setting to NULL or any other deterministic value).
Sergei Turchanov
90f2e7607a