Fix wallet unload race condition

Currently it's possible for ReleaseWallet to delete the CWallet pointer while
it is processing BlockConnected, etc chain notifications.

To fix this, unregister from notifications earlier in UnloadWallet instead of
ReleaseWallet, and use a new RegisterSharedValidationInterface function to
prevent the CValidationInterface shared_ptr from being deleted until the last
notification is actually finished.
This commit is contained in:
Russell Yanofsky
2020-03-10 15:46:20 -04:00
committed by João Barbosa
parent 3e50fdbe4e
commit ab31b9d6fe
9 changed files with 62 additions and 42 deletions

View File

@@ -75,8 +75,10 @@ CMainSignals& GetMainSignals()
return g_signals;
}
void RegisterValidationInterface(CValidationInterface* pwalletIn) {
ValidationInterfaceConnections& conns = g_signals.m_internals->m_connMainSignals[pwalletIn];
void RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface> pwalletIn) {
// Each connection captures pwalletIn to ensure that each callback is
// executed before pwalletIn is destroyed. For more details see #18338.
ValidationInterfaceConnections& conns = g_signals.m_internals->m_connMainSignals[pwalletIn.get()];
conns.UpdatedBlockTip = g_signals.m_internals->UpdatedBlockTip.connect(std::bind(&CValidationInterface::UpdatedBlockTip, pwalletIn, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));
conns.TransactionAddedToMempool = g_signals.m_internals->TransactionAddedToMempool.connect(std::bind(&CValidationInterface::TransactionAddedToMempool, pwalletIn, std::placeholders::_1));
conns.BlockConnected = g_signals.m_internals->BlockConnected.connect(std::bind(&CValidationInterface::BlockConnected, pwalletIn, std::placeholders::_1, std::placeholders::_2));
@@ -87,6 +89,18 @@ void RegisterValidationInterface(CValidationInterface* pwalletIn) {
conns.NewPoWValidBlock = g_signals.m_internals->NewPoWValidBlock.connect(std::bind(&CValidationInterface::NewPoWValidBlock, pwalletIn, std::placeholders::_1, std::placeholders::_2));
}
void RegisterValidationInterface(CValidationInterface* callbacks)
{
// Create a shared_ptr with a no-op deleter - CValidationInterface lifecycle
// is managed by the caller.
RegisterSharedValidationInterface({callbacks, [](CValidationInterface*){}});
}
void UnregisterSharedValidationInterface(std::shared_ptr<CValidationInterface> callbacks)
{
UnregisterValidationInterface(callbacks.get());
}
void UnregisterValidationInterface(CValidationInterface* pwalletIn) {
if (g_signals.m_internals) {
g_signals.m_internals->m_connMainSignals.erase(pwalletIn);