Fix asan build of wasmtime-fiber

This commit fixes an issue with bytecodealliance#9304 where the asan build of
`wasmtime-fiber` has broken which was preventing oss-fuzz from updating
and making progress.

.github/workflows/main.yml

@@ -560,9 +560,9 @@ jobs:
  - run: sudo apt-get update && sudo apt install -y ocaml-nox ocamlbuild ocaml-findlib libzarith-ocaml-dev
  - run: cargo fetch
  working-directory: ./fuzz
- - run: cargo fuzz build --dev -s none
- - run: cargo fuzz build --dev -s none --fuzz-dir ./cranelift/isle/fuzz
- - run: cargo fuzz build --dev -s none --fuzz-dir ./crates/environ/fuzz --features component-model
+ - run: cargo fuzz build --dev
+ - run: cargo fuzz build --dev --fuzz-dir ./cranelift/isle/fuzz
+ - run: cargo fuzz build --dev --fuzz-dir ./crates/environ/fuzz --features component-model
 
  # common logic to cancel the entire run if this job fails
  - run: gh run cancel ${{ github.run_id }}

crates/fiber/src/unix.rs

@@ -458,6 +458,10 @@ mod asan {
  let end = base + self.0.mapping_len;
  base + page_size()..end
  }
+
+ fn guard_range(&self) -> Range<*mut u8> {
+ self.0.mapping_base..self.0.mapping_base.wrapping_add(page_size())
+ }
  }
 
  impl Drop for AsanFiberStack {