diff options
| -rw-r--r-- | src/qt/clientmodel.cpp | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp index f15921c5bc..c1d358f7f6 100644 --- a/src/qt/clientmodel.cpp +++ b/src/qt/clientmodel.cpp @@ -116,9 +116,23 @@ int ClientModel::getNumBlocks() const uint256 ClientModel::getBestBlockHash() { + uint256 tip{WITH_LOCK(m_cached_tip_mutex, return m_cached_tip_blocks)}; + + if (!tip.IsNull()) { + return tip; + } + + // Lock order must be: first `cs_main`, then `m_cached_tip_mutex`. + // The following will lock `cs_main` (and release it), so we must not + // own `m_cached_tip_mutex` here. + tip = m_node.getBestBlockHash(); + LOCK(m_cached_tip_mutex); + // We checked that `m_cached_tip_blocks` is not null above, but then we + // released the mutex `m_cached_tip_mutex`, so it could have changed in the + // meantime. Thus, check again. if (m_cached_tip_blocks.IsNull()) { - m_cached_tip_blocks = m_node.getBestBlockHash(); + m_cached_tip_blocks = tip; } return m_cached_tip_blocks; } |