8228631: Fix inconsistent OopStorage::Block owner usage
Summary: Only use Block's owner member for address validation.
Reviewed-by: tschatzl, pliden
--- a/src/hotspot/share/gc/shared/oopStorage.cpp Fri Jul 26 13:32:59 2019 -0700
+++ b/src/hotspot/share/gc/shared/oopStorage.cpp Fri Jul 26 20:15:13 2019 -0400
@@ -208,7 +208,7 @@
OopStorage::Block::Block(const OopStorage* owner, void* memory) :
_data(),
_allocated_bitmask(0),
- _owner(owner),
+ _owner_address(reinterpret_cast<intptr_t>(owner)),
_memory(memory),
_active_index(0),
_allocation_list_entry(),
@@ -228,7 +228,7 @@
// Clear fields used by block_for_ptr and entry validation, which
// might help catch bugs. Volatile to prevent dead-store elimination.
const_cast<uintx volatile&>(_allocated_bitmask) = 0;
- const_cast<OopStorage* volatile&>(_owner) = NULL;
+ const_cast<intptr_t volatile&>(_owner_address) = 0;
}
size_t OopStorage::Block::allocation_size() {
@@ -356,9 +356,7 @@
intptr_t owner_addr = reinterpret_cast<intptr_t>(owner);
for (unsigned i = 0; i < section_count; ++i, section += section_size) {
Block* candidate = reinterpret_cast<Block*>(section);
- intptr_t* candidate_owner_addr
- = reinterpret_cast<intptr_t*>(&candidate->_owner);
- if (SafeFetchN(candidate_owner_addr, 0) == owner_addr) {
+ if (SafeFetchN(&candidate->_owner_address, 0) == owner_addr) {
return candidate;
}
}
@@ -609,7 +607,7 @@
if ((releasing == old_allocated) || is_full_bitmask(old_allocated)) {
// Log transitions. Both transitions are possible in a single update.
if (log_is_enabled(Debug, oopstorage, blocks)) {
- log_release_transitions(releasing, old_allocated, _owner, this);
+ log_release_transitions(releasing, old_allocated, owner, this);
}
// Attempt to claim responsibility for adding this block to the deferred
// list, by setting the link to non-NULL by self-looping. If this fails,
@@ -634,7 +632,7 @@
owner->record_needs_cleanup();
}
log_debug(oopstorage, blocks)("%s: deferred update " PTR_FORMAT,
- _owner->name(), p2i(this));
+ owner->name(), p2i(this));
}
}
// Release hold on empty block deletion.
--- a/src/hotspot/share/gc/shared/oopStorage.inline.hpp Fri Jul 26 13:32:59 2019 -0700
+++ b/src/hotspot/share/gc/shared/oopStorage.inline.hpp Fri Jul 26 20:15:13 2019 -0400
@@ -137,7 +137,7 @@
static const unsigned _data_pos = 0; // Position of _data.
volatile uintx _allocated_bitmask; // One bit per _data element.
- const OopStorage* _owner;
+ intptr_t _owner_address;
void* _memory; // Unaligned storage containing block.
size_t _active_index;
AllocationListEntry _allocation_list_entry;