diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index c050d5b2..4c70121c 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -19,7 +19,7 @@ jobs:
         uses: actions-rs/toolchain@v1.0.7
         with:
           profile: minimal
-          toolchain: stable
+          toolchain: 1.56.1
           override: true
           components: rustfmt, clippy
       
@@ -35,6 +35,11 @@ jobs:
       - name: Remove pre-generated prost files to force regeneration
         run: rm proto/*.rs
 
+      - name: Specify dependency version for old Rust
+        run: |
+          sed -i "s|inferno = { version = \"0.11\"|inferno = { version = \"=0.11.1\"|g" ./Cargo.toml
+          sed -i "s|criterion = \"0.4\"|criterion = \"=0.3.0\"\ncsv = \"=1.1.0\"|g" Cargo.toml
+
       - name: Run cargo clippy prost
         uses: actions-rs/cargo@v1.0.3
         with:
@@ -74,6 +79,7 @@ jobs:
             target: aarch64-unknown-linux-gnu
           - os: macos-latest
             target: x86_64-unknown-linux-musl
+      fail-fast: false
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -88,6 +94,13 @@ jobs:
           target: ${{ matrix.target }}
           override: true
 
+      - name: Specify dependency version for old Rust
+        if: ${{ matrix.toolchain == '1.56.1' }}
+        run: |
+          # sed -i is not compatible with Mac OS
+          mv Cargo.toml Cargo.toml.bak
+          sed "s|inferno = { version = \"0.11\"|inferno = { version = \"=0.11.1\"|g" Cargo.toml.bak > ./Cargo.toml
+
       - name: Run cargo build prost
         uses: actions-rs/cargo@v1.0.3
         with:
@@ -125,6 +138,7 @@ jobs:
             target: x86_64-unknown-linux-gnu
           - os: macos-latest
             target: x86_64-unknown-linux-musl
+      fail-fast: false
     runs-on: ${{ matrix.os }}
 
     steps:
diff --git a/src/addr_validate.rs b/src/addr_validate.rs
index 9e9a34c6..1b092caf 100644
--- a/src/addr_validate.rs
+++ b/src/addr_validate.rs
@@ -1,13 +1,25 @@
-use std::{cell::RefCell, mem::size_of};
+use std::{cell::UnsafeCell, mem::size_of};
 
 use nix::{
     errno::Errno,
     unistd::{close, read, write},
 };
 
-thread_local! {
-    static MEM_VALIDATE_PIPE: RefCell<[i32; 2]> = RefCell::new([-1, -1]);
+struct Pipes {
+    fd: UnsafeCell<[i32; 2]>,
 }
+unsafe impl Sync for Pipes {}
+impl std::ops::Deref for Pipes {
+    type Target = UnsafeCell<[i32; 2]>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.fd
+    }
+}
+
+static MEM_VALIDATE_PIPE: Pipes = Pipes {
+    fd: UnsafeCell::new([-1, -1]),
+};
 
 #[inline]
 #[cfg(target_os = "linux")]
@@ -42,56 +54,50 @@ fn create_pipe() -> nix::Result<(i32, i32)> {
 }
 
 fn open_pipe() -> nix::Result<()> {
-    MEM_VALIDATE_PIPE.with(|pipes| {
-        let mut pipes = pipes.borrow_mut();
+    let pipes = unsafe { &mut *MEM_VALIDATE_PIPE.get() };
 
-        // ignore the result
-        let _ = close(pipes[0]);
-        let _ = close(pipes[1]);
+    // ignore the result
+    let _ = close(pipes[0]);
+    let _ = close(pipes[1]);
 
-        let (read_fd, write_fd) = create_pipe()?;
+    let (read_fd, write_fd) = create_pipe()?;
 
-        pipes[0] = read_fd;
-        pipes[1] = write_fd;
+    pipes[0] = read_fd;
+    pipes[1] = write_fd;
 
-        Ok(())
-    })
+    Ok(())
 }
 
 pub fn validate(addr: *const libc::c_void) -> bool {
     const CHECK_LENGTH: usize = 2 * size_of::<*const libc::c_void>() / size_of::<u8>();
 
     // read data in the pipe
-    let valid_read = MEM_VALIDATE_PIPE.with(|pipes| {
-        let pipes = pipes.borrow();
-        loop {
-            let mut buf = [0u8; CHECK_LENGTH];
-
-            match read(pipes[0], &mut buf) {
-                Ok(bytes) => break bytes > 0,
-                Err(_err @ Errno::EINTR) => continue,
-                Err(_err @ Errno::EAGAIN) => break true,
-                Err(_) => break false,
-            }
+    let pipes = unsafe { &*MEM_VALIDATE_PIPE.get() };
+    let valid_read = loop {
+        let mut buf = [0u8; CHECK_LENGTH];
+
+        match read(pipes[0], &mut buf) {
+            Ok(bytes) => break bytes > 0,
+            Err(_err @ Errno::EINTR) => continue,
+            Err(_err @ Errno::EAGAIN) => break true,
+            Err(_) => break false,
         }
-    });
+    };
 
     if !valid_read && open_pipe().is_err() {
         return false;
     }
 
-    MEM_VALIDATE_PIPE.with(|pipes| {
-        let pipes = pipes.borrow();
-        loop {
-            let buf = unsafe { std::slice::from_raw_parts(addr as *const u8, CHECK_LENGTH) };
+    let pipes = unsafe { &*MEM_VALIDATE_PIPE.get() };
+    loop {
+        let buf = unsafe { std::slice::from_raw_parts(addr as *const u8, CHECK_LENGTH) };
 
-            match write(pipes[1], buf) {
-                Ok(bytes) => break bytes > 0,
-                Err(_err @ Errno::EINTR) => continue,
-                Err(_) => break false,
-            }
+        match write(pipes[1], buf) {
+            Ok(bytes) => break bytes > 0,
+            Err(_err @ Errno::EINTR) => continue,
+            Err(_) => break false,
         }
-    })
+    }
 }
 
 #[cfg(test)]