diff --git a/fuzzer/Cargo.toml b/fuzzer/Cargo.toml
index 9ea13ec3..52f8bfc5 100644
--- a/fuzzer/Cargo.toml
+++ b/fuzzer/Cargo.toml
@@ -19,7 +19,7 @@ byteorder = "1.2"
 chrono = "0.4"
 priority-queue = "0.6"
 num_cpus = "1.0"
-derive_more = "0.15"
+derive_more = "0.99"
 colored = "1.6"
 serde="1.0"
 serde_derive = "1.0"
diff --git a/fuzzer/src/bind_cpu.rs b/fuzzer/src/bind_cpu.rs
index a18753e7..adb27760 100644
--- a/fuzzer/src/bind_cpu.rs
+++ b/fuzzer/src/bind_cpu.rs
@@ -94,9 +94,8 @@ pub fn bind_thread_to_cpu_core(_cid: usize) {
 
 #[cfg(target_os = "linux")]
 pub fn bind_thread_to_cpu_core(cid: usize) {
-    // let tid = unsafe { libc::pthread_self() };
     unsafe {
-        let mut c: libc::cpu_set_t = mem::uninitialized();
+        let mut c: libc::cpu_set_t = mem::zeroed();
         libc::CPU_ZERO(&mut c);
         libc::CPU_SET(cid, &mut c);
         if libc::sched_setaffinity(0, mem::size_of_val(&c), &c as *const libc::cpu_set_t) != 0 {
diff --git a/fuzzer/src/executor/limit.rs b/fuzzer/src/executor/limit.rs
index 3cad99cc..0ff18308 100644
--- a/fuzzer/src/executor/limit.rs
+++ b/fuzzer/src/executor/limit.rs
@@ -40,7 +40,7 @@ impl SetLimit for Command {
             Ok(())
         };
 
-        self.before_exec(func)
+        unsafe { self.pre_exec(func) }
     }
 
     fn setsid(&mut self) -> &mut Self {
@@ -50,7 +50,7 @@ impl SetLimit for Command {
             };
             Ok(())
         };
-        self.before_exec(func)
+        unsafe { self.pre_exec(func) }
     }
 
     fn pipe_stdin(&mut self, fd: RawFd, is_stdin: bool) -> &mut Self {
@@ -65,7 +65,7 @@ impl SetLimit for Command {
                 }
                 Ok(())
             };
-            self.before_exec(func)
+            unsafe { self.pre_exec(func) }
         } else {
             self
         }
diff --git a/fuzzer/src/track/load_pin_data.rs b/fuzzer/src/track/load_pin_data.rs
index 712ef187..0db602ef 100644
--- a/fuzzer/src/track/load_pin_data.rs
+++ b/fuzzer/src/track/load_pin_data.rs
@@ -4,38 +4,26 @@ use angora_common::tag::TagSeg;
 use std::fs::File;
 use std::io::{self, Read};
 use std::{collections::HashMap, path::Path};
+use std::mem::MaybeUninit;
+use std;
 
 fn read_struct<T, R: Read>(mut read: R) -> io::Result<T> {
-    let num_bytes = ::std::mem::size_of::<T>();
-    unsafe {
-        let mut s = ::std::mem::uninitialized();
-        let buffer = ::std::slice::from_raw_parts_mut(&mut s as *mut T as *mut u8, num_bytes);
-        match read.read_exact(buffer) {
-            Ok(()) => Ok(s),
-            Err(e) => {
-                ::std::mem::forget(s);
-                Err(e)
-            }
-        }
-    }
+    let mut obj = MaybeUninit::<T>::uninit();
+    let num_bytes = std::mem::size_of::<T>();
+    let buffer = unsafe{ std::slice::from_raw_parts_mut(obj.as_mut_ptr() as *mut u8, num_bytes) };
+    read.read_exact(buffer)?;
+    Ok(unsafe { obj.assume_init() })
 }
 
 fn read_vector<T, R: Read>(mut read: R, size: usize) -> io::Result<Vec<T>> {
     let mut vec = Vec::<T>::with_capacity(size);
     if size > 0 {
-        unsafe {
-            vec.set_len(size);
-            let num_bytes = ::std::mem::size_of::<T>() * size;
-            let buffer =
-                ::std::slice::from_raw_parts_mut((&mut vec[..]).as_ptr() as *mut u8, num_bytes);
-            match read.read_exact(buffer) {
-                Ok(()) => Ok(vec),
-                Err(e) => Err(e),
-            }
-        }
-    } else {
-        Ok(vec)
-    }
+        let num_bytes = std::mem::size_of::<T>() * size;
+        unsafe { vec.set_len(size) };
+        let buffer = unsafe {std::slice::from_raw_parts_mut((&mut vec[..]).as_mut_ptr() as *mut u8, num_bytes) } ;
+        read.read_exact(buffer)?;
+    } 
+    Ok(vec)
 }
 
 pub fn get_log_data_pin(out_f: &Path) -> io::Result<LogData> {
diff --git a/runtime_fast/src/fast.rs b/runtime_fast/src/fast.rs
index 0535ac5c..8b46c9f9 100644
--- a/runtime_fast/src/fast.rs
+++ b/runtime_fast/src/fast.rs
@@ -1,8 +1,9 @@
 use super::{shm_conds, forkcli, shm_branches};
 use std::ops::DerefMut;
 
-use std::sync::{Once, ONCE_INIT};
-static START: Once = ONCE_INIT;
+use std::sync::Once;
+
+static START: Once = Once::new();
 
 #[ctor]
 fn fast_init() {