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crates/runtime/src/memory.rs

@@ -2,10 +2,10 @@
 //!
 //! `RuntimeLinearMemory` is to WebAssembly linear memories what `Table` is to WebAssembly tables.
 
-use crate::instance::MemFdSlot;
-use crate::memfd::MemoryMemFd;
 use crate::mmap::Mmap;
 use crate::vmcontext::VMMemoryDefinition;
+use crate::MemFdSlot;
+use crate::MemoryMemFd;
 use crate::Store;
 use anyhow::Error;
 use anyhow::{bail, format_err, Result};
@@ -162,6 +162,13 @@ impl MmapMemory {
                 let len = request_bytes - pre_guard_bytes;
                 let mut memfd_slot = MemFdSlot::create(base as *mut _, len);
                 memfd_slot.instantiate(minimum, Some(image))?;
+                unsafe {
+                    // On drop, we will unmap our mmap'd range that
+                    // this memfd_slot was mapped on top of, so there
+                    // is no need for the memfd_slot to wipe it with
+                    // an anonymous mapping first.
+                    memfd_slot.no_clear_on_drop();
+                }
                 Some(memfd_slot)
             }
             None => None,