diff --git a/internal/wasm/memory.go b/internal/wasm/memory.go index 947b16112d..1a23dc4602 100644 --- a/internal/wasm/memory.go +++ b/internal/wasm/memory.go @@ -52,7 +52,8 @@ type MemoryInstance struct { definition api.MemoryDefinition // Mux is used in interpreter mode to prevent overlapping calls to atomic instructions, - // introduced with WebAssembly threads proposal. + // introduced with WebAssembly threads proposal, and in compiler mode to make memory modifications + // within Grow non-racy for the Go race detector. Mux sync.Mutex // waiters implements atomic wait and notify. It is implemented similarly to golang.org/x/sync/semaphore, @@ -227,6 +228,11 @@ func MemoryPagesToBytesNum(pages uint32) (bytesNum uint64) { // Grow implements the same method as documented on api.Memory. func (m *MemoryInstance) Grow(delta uint32) (result uint32, ok bool) { + if m.Shared { + m.Mux.Lock() + defer m.Mux.Unlock() + } + currentPages := m.Pages() if delta == 0 { return currentPages, true