diff --git a/src/cgroups/common.rs b/src/cgroups/common.rs
index b25a8906e..48bf51970 100644
--- a/src/cgroups/common.rs
+++ b/src/cgroups/common.rs
@@ -6,7 +6,7 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use anyhow::{anyhow, Result};
+use anyhow::{bail, Result};
 use nix::unistd::Pid;
 use oci_spec::LinuxResources;
 use procfs::process::Process;
@@ -74,30 +74,28 @@ pub fn create_cgroup_manager<P: Into<PathBuf>>(cgroup_path: P) -> Result<Box<dyn
     match (cgroup_mount, cgroup2_mount) {
         (Some(_), None) => {
             log::info!("cgroup manager V1 will be used");
-            return Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?));
+            Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?))
         }
         (None, Some(cgroup2)) => {
             log::info!("cgroup manager V2 will be used");
-            return Ok(Box::new(v2::manager::Manager::new(
+            Ok(Box::new(v2::manager::Manager::new(
                 cgroup2.mount_point,
                 cgroup_path.into(),
-            )?));
+            )?))
         }
         (Some(_), Some(cgroup2)) => {
             let cgroup_override = env::var("YOUKI_PREFER_CGROUPV2");
             match cgroup_override {
                 Ok(v) if v == "true" => {
                     log::info!("cgroup manager V2 will be used");
-                    return Ok(Box::new(v2::manager::Manager::new(
+                    Ok(Box::new(v2::manager::Manager::new(
                         cgroup2.mount_point,
                         cgroup_path.into(),
-                    )?));
-                }
-                _ => {
-                    return Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?))
+                    )?))
                 }
+                _ => Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?)),
             }
         }
-        _ => return Err(anyhow!("could not find cgroup filesystem")),
+        _ => bail!("could not find cgroup filesystem"),
     }
 }
diff --git a/src/cgroups/v2/cpu.rs b/src/cgroups/v2/cpu.rs
index 50bae166f..26b1e17be 100644
--- a/src/cgroups/v2/cpu.rs
+++ b/src/cgroups/v2/cpu.rs
@@ -71,11 +71,11 @@ impl Cpu {
     }
 
     fn is_realtime_requested(cpu: &LinuxCpu) -> bool {
-        if let Some(_) = cpu.realtime_period {
+        if cpu.realtime_period.is_some() {
             return true;
         }
 
-        if let Some(_) = cpu.realtime_runtime {
+        if cpu.realtime_runtime.is_some() {
             return true;
         }
 
@@ -92,7 +92,7 @@ mod tests {
     fn setup(testname: &str, cgroup_file: &str) -> (PathBuf, PathBuf) {
         let tmp = create_temp_dir(testname).expect("create temp directory for test");
         let cgroup_file = set_fixture(&tmp, cgroup_file, "")
-            .expect(&format!("set test fixture for {}", cgroup_file));
+            .unwrap_or_else(|_| panic!("set test fixture for {}", cgroup_file));
 
         (tmp, cgroup_file)
     }
@@ -102,15 +102,15 @@ mod tests {
         // arrange
         let (tmp, weight) = setup("test_set_shares", CGROUP_CPU_WEIGHT);
         let _ = set_fixture(&tmp, CGROUP_CPU_MAX, "")
-            .expect(&format!("set test fixture for {}", CGROUP_CPU_MAX));
+            .unwrap_or_else(|_| panic!("set test fixture for {}", CGROUP_CPU_MAX));
         let cpu = LinuxCpuBuilder::new().with_shares(22000).build();
 
         // act
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(weight).expect(&format!("read {} file content", CGROUP_CPU_WEIGHT));
+        let content = fs::read_to_string(weight)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_WEIGHT));
         assert_eq!(content, 840.to_string());
     }
 
@@ -125,8 +125,8 @@ mod tests {
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(max).expect(&format!("read {} file content", CGROUP_CPU_MAX));
+        let content = fs::read_to_string(max)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_MAX));
         assert_eq!(content, format!("{} {}", QUOTA, DEFAULT_PERIOD))
     }
 
@@ -140,8 +140,8 @@ mod tests {
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(max).expect(&format!("read {} file content", CGROUP_CPU_MAX));
+        let content = fs::read_to_string(max)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_MAX));
         assert_eq!(
             content,
             format!("{} {}", UNRESTRICTED_QUOTA, DEFAULT_PERIOD)
@@ -159,8 +159,8 @@ mod tests {
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(max).expect(&format!("read {} file content", CGROUP_CPU_MAX));
+        let content = fs::read_to_string(max)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_MAX));
         assert_eq!(content, format!("{} {}", UNRESTRICTED_QUOTA, PERIOD))
     }
 
@@ -174,8 +174,8 @@ mod tests {
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(max).expect(&format!("read {} file content", CGROUP_CPU_MAX));
+        let content = fs::read_to_string(max)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_MAX));
         assert_eq!(
             content,
             format!("{} {}", UNRESTRICTED_QUOTA, DEFAULT_PERIOD)
@@ -197,8 +197,8 @@ mod tests {
         Cpu::apply(&tmp, &cpu).expect("apply cpu");
 
         // assert
-        let content =
-            fs::read_to_string(max).expect(&format!("read {} file content", CGROUP_CPU_MAX));
+        let content = fs::read_to_string(max)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPU_MAX));
         assert_eq!(content, format!("{} {}", QUOTA, PERIOD));
     }
 
diff --git a/src/cgroups/v2/cpuset.rs b/src/cgroups/v2/cpuset.rs
index 825b44dc7..3fe0e5756 100644
--- a/src/cgroups/v2/cpuset.rs
+++ b/src/cgroups/v2/cpuset.rs
@@ -45,7 +45,7 @@ mod tests {
     fn setup(testname: &str, cgroup_file: &str) -> (PathBuf, PathBuf) {
         let tmp = create_temp_dir(testname).expect("create temp directory for test");
         let cgroup_file = set_fixture(&tmp, cgroup_file, "")
-            .expect(&format!("set test fixture for {}", cgroup_file));
+            .unwrap_or_else(|_| panic!("set test fixture for {}", cgroup_file));
 
         (tmp, cgroup_file)
     }
@@ -60,8 +60,8 @@ mod tests {
         CpuSet::apply(&tmp, &cpuset).expect("apply cpuset");
 
         // assert
-        let content =
-            fs::read_to_string(&cpus).expect(&format!("read {} file content", CGROUP_CPUSET_CPUS));
+        let content = fs::read_to_string(&cpus)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPUSET_CPUS));
         assert_eq!(content, "1-3");
     }
 
@@ -75,8 +75,8 @@ mod tests {
         CpuSet::apply(&tmp, &cpuset).expect("apply cpuset");
 
         // assert
-        let content =
-            fs::read_to_string(&mems).expect(&format!("read {} file content", CGROUP_CPUSET_MEMS));
+        let content = fs::read_to_string(&mems)
+            .unwrap_or_else(|_| panic!("read {} file content", CGROUP_CPUSET_MEMS));
         assert_eq!(content, "1-3");
     }
 }
diff --git a/src/create.rs b/src/create.rs
index 91ccb0df4..5cd967c52 100644
--- a/src/create.rs
+++ b/src/create.rs
@@ -18,7 +18,7 @@ use crate::stdio::FileDescriptor;
 use crate::tty;
 use crate::utils;
 use crate::{capabilities, command::Command};
-use oci_spec;
+
 #[derive(Clap, Debug)]
 pub struct Create {
     #[clap(short, long)]
diff --git a/src/process/fork.rs b/src/process/fork.rs
index ebc75230f..07f3a6cf9 100644
--- a/src/process/fork.rs
+++ b/src/process/fork.rs
@@ -17,7 +17,6 @@ use crate::container::ContainerStatus;
 use crate::process::{child, init, parent, Process};
 use crate::utils;
 use crate::{cond::Cond, container::Container};
-use oci_spec;
 
 pub fn fork_first<P: AsRef<Path>>(
     pid_file: Option<P>,