diff --git a/kernel/src/lib.rs b/kernel/src/lib.rs
index bc19e2cec..fd8b6e36a 100644
--- a/kernel/src/lib.rs
+++ b/kernel/src/lib.rs
@@ -33,7 +33,7 @@
 use ostd::{
     arch::qemu::{exit_qemu, QemuExitCode},
     boot,
-    cpu::PinCurrentCpu,
+    cpu::{CpuId, CpuSet, PinCurrentCpu},
 };
 use process::Process;
 
@@ -81,8 +81,11 @@ pub fn main() {
     ostd::boot::smp::register_ap_entry(ap_init);
 
     // Spawn the first kernel thread on BSP.
+    let mut affinity = CpuSet::new_empty();
+    affinity.add(CpuId::bsp());
     ThreadOptions::new(init_thread)
         .priority(Priority::idle())
+        .cpu_affinity(affinity)
         .spawn();
 }