backport: graph: fix various races #10433
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The PubKey method had a race condition where concurrent calls could all pass the nil check and race to write to the cached pubKey field. This is a classic check-then-act race. Remove the caching entirely to fix the race. The overhead of parsing a public key is minimal and doesn't justify the added complexity and race risk of caching.
Summary of ChangesHello @ellemouton, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request backports critical fixes for several race conditions identified within the channel graph database. The changes primarily focus on enhancing thread safety by eliminating problematic caching patterns in public key parsing methods and introducing proper mutex protection for shared cache resources during block disconnection events. This ensures the integrity and consistency of the graph data under concurrent operations. Highlights
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Code Review
This pull request is a backport that fixes several race conditions in the channel graph database. The changes remove racy check-then-act caching logic for public keys in Node and ChannelEdgeInfo models by parsing them from bytes on each call. Additionally, it adds proper mutex protection for cache access in DisconnectBlockAtHeight to prevent data races. The fixes are correct and improve the concurrency safety of the graph database. The release note update is also accurate.
Both NodeKey1 and NodeKey2 methods had the same race condition as the Node.PubKey method, where concurrent calls could race to write to the cached fields. Remove the caching for the same reasons: parsing overhead is minimal and doesn't justify the complexity and race risk.
The DisconnectBlockAtHeight method was modifying the rejectCache and chanCache without holding the cacheMu lock. This caused races with other operations that properly held the lock, such as AddChannelEdge which modifies the caches in its OnCommit callback while the batch scheduler holds cacheMu. Fix by acquiring cacheMu before removing channels from the caches.
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backport of #10420