diff --git a/core/native/src/main/scala/cats/effect/Signal.scala b/core/native/src/main/scala/cats/effect/Signal.scala
index 6d678211df..9a0d9bc2c4 100644
--- a/core/native/src/main/scala/cats/effect/Signal.scala
+++ b/core/native/src/main/scala/cats/effect/Signal.scala
@@ -34,7 +34,7 @@ import java.io.IOException
 private object Signal {
 
   private[this] def mkPipe() = if (isLinux || isMac) {
-    val fd = stackalloc[CInt](2)
+    val fd = stackalloc[CInt](2.toULong)
     if (pipe(fd) != 0)
       throw new IOException(fromCString(strerror(errno)))
 
diff --git a/core/native/src/main/scala/cats/effect/unsafe/EpollSystem.scala b/core/native/src/main/scala/cats/effect/unsafe/EpollSystem.scala
index 9874edb58e..4e8dfd28d0 100644
--- a/core/native/src/main/scala/cats/effect/unsafe/EpollSystem.scala
+++ b/core/native/src/main/scala/cats/effect/unsafe/EpollSystem.scala
@@ -185,7 +185,7 @@ object EpollSystem extends PollingSystem {
 
     private[EpollSystem] def poll(timeout: Long): Boolean = {
 
-      val events = stackalloc[epoll_event](MaxEvents.toLong)
+      val events = stackalloc[epoll_event](MaxEvents.toULong)
       var polled = false
 
       @tailrec
diff --git a/core/native/src/main/scala/cats/effect/unsafe/KqueueSystem.scala b/core/native/src/main/scala/cats/effect/unsafe/KqueueSystem.scala
index 3a26a4eb6d..0e7aae2395 100644
--- a/core/native/src/main/scala/cats/effect/unsafe/KqueueSystem.scala
+++ b/core/native/src/main/scala/cats/effect/unsafe/KqueueSystem.scala
@@ -170,7 +170,7 @@ object KqueueSystem extends PollingSystem {
 
     private[KqueueSystem] def poll(timeout: Long): Boolean = {
 
-      val eventlist = stackalloc[kevent64_s](MaxEvents.toLong)
+      val eventlist = stackalloc[kevent64_s](MaxEvents.toULong)
       var polled = false
 
       @tailrec
diff --git a/tests/native/src/test/scala/cats/effect/FileDescriptorPollerSpec.scala b/tests/native/src/test/scala/cats/effect/FileDescriptorPollerSpec.scala
index 543d71b0a6..879f122fdc 100644
--- a/tests/native/src/test/scala/cats/effect/FileDescriptorPollerSpec.scala
+++ b/tests/native/src/test/scala/cats/effect/FileDescriptorPollerSpec.scala
@@ -69,7 +69,7 @@ class FileDescriptorPollerSpec extends BaseSpec {
     Resource
       .make {
         IO {
-          val fd = stackalloc[CInt](2)
+          val fd = stackalloc[CInt](2.toULong)
           if (unistd.pipe(fd) != 0)
             throw new IOException(fromCString(strerror(errno)))
           (fd(0), fd(1))