From fa97a528d6382a0163d5aa7d37ecbf93579b8186 Mon Sep 17 00:00:00 2001 From: MacroFake Date: Tue, 12 Jul 2022 17:49:21 +0200 Subject: [PATCH] Fix UB/data-race in RPCNotifyBlockChange ActiveTip() is *not* thread-safe, as the required ::cs_main lock will be released as ActiveChainstate() returns. ActiveTip() is an alias for ActiveChainstate().m_chain.Tip(), so m_chain may be involved in a data-race (UB). --- src/init.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/init.cpp b/src/init.cpp index 4606b77e9f..d48337db08 100644 --- a/src/init.cpp +++ b/src/init.cpp @@ -1751,12 +1751,12 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info) // At this point, the RPC is "started", but still in warmup, which means it // cannot yet be called. Before we make it callable, we need to make sure // that the RPC's view of the best block is valid and consistent with - // ChainstateManager's ActiveTip. + // ChainstateManager's active tip. // // If we do not do this, RPC's view of the best block will be height=0 and // hash=0x0. This will lead to erroroneous responses for things like // waitforblockheight. - RPCNotifyBlockChange(chainman.ActiveTip()); + RPCNotifyBlockChange(WITH_LOCK(chainman.GetMutex(), return chainman.ActiveTip())); SetRPCWarmupFinished(); uiInterface.InitMessage(_("Done loading").translated);