Device.ShadowMtx.lock();
auto Entry = Device.ShadowPtrMap.find(Pointer_HstPtrBegin);
- // If this pointer is not in the map we need to insert it.
- if (Entry == Device.ShadowPtrMap.end()) {
- // create shadow pointers for this entry
+ // If this pointer is not in the map we need to insert it. If the map
+ // contains a stale entry, we need to update it (e.g. if the pointee was
+ // deallocated and later on is reallocated at another device address). The
+ // latter scenario is the subject of LIT test env/base_ptr_ref_count.c. An
+ // entry is removed from ShadowPtrMap only when the PTR of a PTR_AND_OBJ
+ // pair is deallocated, not when the OBJ is deallocated. In
+ // env/base_ptr_ref_count.c the PTR is a global "declare target" pointer,
+ // so it stays in the map for the lifetime of the application. When the
+ // OBJ is deallocated and later on allocated again (at a different device
+ // address), ShadowPtrMap still contains an entry for Pointer_HstPtrBegin
+ // which is stale, pointing to the old ExpectedTgtPtrBase of the OBJ.
+ if (Entry == Device.ShadowPtrMap.end() ||
+ Entry->second.TgtPtrVal != ExpectedTgtPtrBase) {
+ // create or update shadow pointers for this entry
Device.ShadowPtrMap[Pointer_HstPtrBegin] = {
HstPtrBase, PointerTgtPtrBegin, ExpectedTgtPtrBase};
UpdateDevPtr = true;