fix(op-supernode): guard chain container vn against torn interface read#20211
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fix(op-supernode): guard chain container vn against torn interface read#20211
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Supernode.Start fires the Interop activity and chain-container goroutines in parallel. Interop's checkChainsReady immediately calls c.OptimisticAt -> c.SyncStatus, which reads c.vn while the chain container is concurrently assigning it in its restart loop. A torn two-word interface read can yield (type=*simpleVirtualNode, data=nil); the `c.vn == nil` guard returns false, the method dispatches on a nil receiver, and v.mu.Lock() panics at offset 0x58 (the mu field inside simpleVirtualNode). Protect c.vn with a sync.RWMutex and route all reads/writes through getVN/setVN helpers so every method takes one consistent snapshot. Also add nil-receiver guards on the *simpleVirtualNode methods as a defense against typed-nil interfaces slipping through in tests or future refactors. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ajsutton
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Apr 21, 2026
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| if v == nil { | ||
| return eth.BlockID{}, ErrVirtualNodeNotRunning | ||
| } |
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Checking if self is nil is a weird pattern - we probably should just put these checks in the calling code.
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Fixes panic at: https://app.circleci.com/pipelines/github/ethereum-optimism/optimism/123123/workflows/65b0b312-f33d-4a35-b114-b5941ee8719b/jobs/4873005
Supernode.Start fires the Interop activity and chain-container goroutines in parallel. Interop's checkChainsReady immediately calls c.OptimisticAt -> c.SyncStatus, which reads c.vn while the chain container is concurrently assigning it in its restart loop. A torn two-word interface read can yield (type=*simpleVirtualNode, data=nil); the
c.vn == nilguard returns false, the method dispatches on a nil receiver, and v.mu.Lock() panics at offset 0x58 (the mu field inside simpleVirtualNode).Protect c.vn with a sync.RWMutex and route all reads/writes through getVN/setVN helpers so every method takes one consistent snapshot. Also add nil-receiver guards on the *simpleVirtualNode methods as a defense against typed-nil interfaces slipping through in tests or future refactors.