diff --git a/examples/malloc_hook.rs b/examples/malloc_hook.rs
deleted file mode 100644
index 56bea852..00000000
--- a/examples/malloc_hook.rs
+++ /dev/null
@@ -1,109 +0,0 @@
-// Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0.
-
-extern crate libc;
-
-use std::ffi::c_void;
-
-#[cfg(not(target_env = "gnu"))]
-#[allow(clippy::wrong_self_convention)]
-#[allow(non_upper_case_globals)]
-static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-#[cfg(target_arch = "riscv64")]
-#[allow(clippy::wrong_self_convention)]
-#[allow(non_upper_case_globals)]
-static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-extern "C" {
-    #[cfg(target_env = "gnu")]
-    #[cfg(not(target_arch = "riscv64"))]
-    static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void>;
-
-    fn malloc(size: usize) -> *mut c_void;
-}
-
-static mut FLAG: bool = false;
-
-extern "C" fn malloc_hook(size: usize) -> *mut c_void {
-    unsafe {
-        FLAG = true;
-    }
-    remove_hook();
-
-    let bt = backtrace::Backtrace::new();
-    println!("{:?}", bt);
-    let p = unsafe { malloc(size) };
-
-    set_hook();
-
-    p
-}
-
-fn set_hook() {
-    unsafe {
-        __malloc_hook = Some(malloc_hook);
-    }
-}
-
-fn remove_hook() {
-    unsafe {
-        __malloc_hook = None;
-    }
-}
-
-#[inline(never)]
-fn is_prime_number(v: usize, prime_numbers: &[usize]) -> bool {
-    if v < 10000 {
-        let r = prime_numbers.binary_search(&v);
-        return r.is_ok();
-    }
-
-    for n in prime_numbers {
-        if v % n == 0 {
-            return false;
-        }
-    }
-
-    true
-}
-
-#[inline(never)]
-fn prepare_prime_numbers() -> Vec<usize> {
-    // bootstrap: Generate a prime table of 0..10000
-    let mut prime_number_table: [bool; 10000] = [true; 10000];
-    prime_number_table[0] = false;
-    prime_number_table[1] = false;
-    for i in 2..10000 {
-        if prime_number_table[i] {
-            let mut v = i * 2;
-            while v < 10000 {
-                prime_number_table[v] = false;
-                v += i;
-            }
-        }
-    }
-    let mut prime_numbers = vec![];
-    for (i, exist) in prime_number_table.iter().enumerate().skip(2) {
-        if *exist {
-            prime_numbers.push(i);
-        }
-    }
-    prime_numbers
-}
-
-fn main() {
-    let prime_numbers = prepare_prime_numbers();
-
-    let _ = pprof::ProfilerGuard::new(100).unwrap();
-
-    loop {
-        let mut _v = 0;
-
-        set_hook();
-        for i in 2..50000 {
-            if is_prime_number(i, &prime_numbers) {
-                _v += 1;
-            }
-        }
-    }
-}
diff --git a/src/collector.rs b/src/collector.rs
index 207de5a4..41b34139 100644
--- a/src/collector.rs
+++ b/src/collector.rs
@@ -360,90 +360,3 @@ mod tests {
         }
     }
 }
-
-#[cfg(test)]
-#[cfg(target_os = "linux")]
-mod malloc_free_test {
-    use super::*;
-    use std::cell::RefCell;
-    use std::collections::BTreeMap;
-    use std::ffi::c_void;
-
-    #[cfg(not(target_env = "gnu"))]
-    #[allow(clippy::wrong_self_convention)]
-    #[allow(non_upper_case_globals)]
-    static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-    #[cfg(target_arch = "riscv64")]
-    #[allow(clippy::wrong_self_convention)]
-    #[allow(non_upper_case_globals)]
-    static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-    extern "C" {
-        #[cfg(target_env = "gnu")]
-        #[cfg(not(target_arch = "riscv64"))]
-        static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void>;
-
-        fn malloc(size: usize) -> *mut c_void;
-    }
-
-    thread_local! {
-        static FLAG: RefCell<bool> = RefCell::new(false);
-    }
-
-    extern "C" fn malloc_hook(size: usize) -> *mut c_void {
-        unsafe {
-            __malloc_hook = None;
-        }
-
-        FLAG.with(|flag| {
-            flag.replace(true);
-        });
-        let p = unsafe { malloc(size) };
-
-        unsafe {
-            __malloc_hook = Some(malloc_hook);
-        }
-
-        p
-    }
-
-    #[test]
-    fn malloc_free() {
-        let mut collector = Collector::new().unwrap();
-        let mut real_map = BTreeMap::new();
-
-        unsafe {
-            __malloc_hook = Some(malloc_hook);
-        }
-
-        for item in 0..(1 << 10) * 4 {
-            for _ in 0..(item % 4) {
-                collector.add(item, 1).unwrap();
-            }
-        }
-        unsafe {
-            __malloc_hook = None;
-        }
-
-        FLAG.with(|flag| {
-            assert!(!*flag.borrow());
-        });
-
-        collector.try_iter().unwrap().for_each(|entry| {
-            test_utils::add_map(&mut real_map, entry);
-        });
-
-        for item in 0..(1 << 10) * 4 {
-            let count = (item % 4) as isize;
-            match real_map.get(&item) {
-                Some(value) => {
-                    assert_eq!(count, *value);
-                }
-                None => {
-                    assert_eq!(count, 0);
-                }
-            }
-        }
-    }
-}
diff --git a/src/profiler.rs b/src/profiler.rs
index c78f0dc2..294b8c55 100644
--- a/src/profiler.rs
+++ b/src/profiler.rs
@@ -464,119 +464,3 @@ impl Profiler {
         if let Ok(()) = self.data.add(frames, 1) {}
     }
 }
-
-#[cfg(test)]
-#[cfg(target_os = "linux")]
-mod tests {
-    use super::*;
-
-    use std::cell::RefCell;
-    use std::ffi::c_void;
-    use std::ptr::null_mut;
-
-    #[cfg(not(target_env = "gnu"))]
-    #[allow(clippy::wrong_self_convention)]
-    #[allow(non_upper_case_globals)]
-    static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-    #[cfg(target_arch = "riscv64")]
-    #[allow(clippy::wrong_self_convention)]
-    #[allow(non_upper_case_globals)]
-    static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void> = None;
-
-    extern "C" {
-        #[cfg(target_env = "gnu")]
-        #[cfg(not(target_arch = "riscv64"))]
-        static mut __malloc_hook: Option<extern "C" fn(size: usize) -> *mut c_void>;
-
-        fn malloc(size: usize) -> *mut c_void;
-    }
-
-    thread_local! {
-        static FLAG: RefCell<bool> = RefCell::new(false);
-    }
-
-    extern "C" fn malloc_hook(size: usize) -> *mut c_void {
-        unsafe {
-            __malloc_hook = None;
-        }
-
-        FLAG.with(|flag| {
-            flag.replace(true);
-        });
-        let p = unsafe { malloc(size) };
-
-        unsafe {
-            __malloc_hook = Some(malloc_hook);
-        }
-
-        p
-    }
-
-    #[inline(never)]
-    fn is_prime_number(v: usize, prime_numbers: &[usize]) -> bool {
-        if v < 10000 {
-            let r = prime_numbers.binary_search(&v);
-            return r.is_ok();
-        }
-
-        for n in prime_numbers {
-            if v % n == 0 {
-                return false;
-            }
-        }
-
-        true
-    }
-
-    #[inline(never)]
-    fn prepare_prime_numbers() -> Vec<usize> {
-        // bootstrap: Generate a prime table of 0..10000
-        let mut prime_number_table: [bool; 10000] = [true; 10000];
-        prime_number_table[0] = false;
-        prime_number_table[1] = false;
-        for i in 2..10000 {
-            if prime_number_table[i] {
-                let mut v = i * 2;
-                while v < 10000 {
-                    prime_number_table[v] = false;
-                    v += i;
-                }
-            }
-        }
-        let mut prime_numbers = vec![];
-        for (i, item) in prime_number_table.iter().enumerate().skip(2) {
-            if *item {
-                prime_numbers.push(i);
-            }
-        }
-        prime_numbers
-    }
-
-    #[cfg(target_os = "linux")]
-    #[test]
-    fn malloc_free() {
-        trigger_lazy();
-
-        let prime_numbers = prepare_prime_numbers();
-
-        let mut _v = 0;
-
-        unsafe {
-            __malloc_hook = Some(malloc_hook);
-        }
-        for i in 2..50000 {
-            if is_prime_number(i, &prime_numbers) {
-                _v += 1;
-                perf_signal_handler(27, null_mut(), null_mut());
-            }
-        }
-        unsafe {
-            __malloc_hook = None;
-        }
-
-        FLAG.with(|flag| {
-            assert!(!*flag.borrow());
-        });
-    }
-}