diff --git a/src/internal/asan/asan.go b/src/internal/asan/asan.go
index 0a8148e5b9..56814ebfb2 100644
--- a/src/internal/asan/asan.go
+++ b/src/internal/asan/asan.go
@@ -13,7 +13,7 @@ import (
 const Enabled = true
 
 //go:linkname Read runtime.asanread
-func Read(addr unsafe.Pointer, len int)
+func Read(addr unsafe.Pointer, len uintptr)
 
 //go:linkname Write runtime.asanwrite
-func Write(addr unsafe.Pointer, len int)
+func Write(addr unsafe.Pointer, len uintptr)
diff --git a/src/internal/asan/noasan.go b/src/internal/asan/noasan.go
index e01b46a104..c510d35146 100644
--- a/src/internal/asan/noasan.go
+++ b/src/internal/asan/noasan.go
@@ -12,8 +12,6 @@ import (
 
 const Enabled = false
 
-func Read(addr unsafe.Pointer, len int) {
-}
+func Read(addr unsafe.Pointer, len uintptr) {}
 
-func Write(addr unsafe.Pointer, len int) {
-}
+func Write(addr unsafe.Pointer, len uintptr) {}
diff --git a/src/syscall/syscall_unix.go b/src/syscall/syscall_unix.go
index 79aac51c8f..ecd5952975 100644
--- a/src/syscall/syscall_unix.go
+++ b/src/syscall/syscall_unix.go
@@ -193,7 +193,7 @@ func Read(fd int, p []byte) (n int, err error) {
 		msan.Write(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	if asan.Enabled && n > 0 {
-		asan.Write(unsafe.Pointer(&p[0]), n)
+		asan.Write(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	return
 }
@@ -217,7 +217,7 @@ func Write(fd int, p []byte) (n int, err error) {
 		msan.Read(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	if asan.Enabled && n > 0 {
-		asan.Read(unsafe.Pointer(&p[0]), n)
+		asan.Read(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	return
 }
@@ -236,7 +236,7 @@ func Pread(fd int, p []byte, offset int64) (n int, err error) {
 		msan.Write(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	if asan.Enabled && n > 0 {
-		asan.Write(unsafe.Pointer(&p[0]), n)
+		asan.Write(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	return
 }
@@ -253,7 +253,7 @@ func Pwrite(fd int, p []byte, offset int64) (n int, err error) {
 		msan.Read(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	if asan.Enabled && n > 0 {
-		asan.Read(unsafe.Pointer(&p[0]), n)
+		asan.Read(unsafe.Pointer(&p[0]), uintptr(n))
 	}
 	return
 }
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 032f814304..59ce2b0206 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -452,7 +452,7 @@ func ReadFile(fd Handle, p []byte, done *uint32, overlapped *Overlapped) error {
 		msan.Write(unsafe.Pointer(&p[0]), uintptr(*done))
 	}
 	if asan.Enabled && *done > 0 {
-		asan.Write(unsafe.Pointer(&p[0]), int(*done))
+		asan.Write(unsafe.Pointer(&p[0]), uintptr(*done))
 	}
 	return err
 }
@@ -469,7 +469,7 @@ func WriteFile(fd Handle, p []byte, done *uint32, overlapped *Overlapped) error
 		msan.Read(unsafe.Pointer(&p[0]), uintptr(*done))
 	}
 	if asan.Enabled && *done > 0 {
-		asan.Read(unsafe.Pointer(&p[0]), int(*done))
+		asan.Read(unsafe.Pointer(&p[0]), uintptr(*done))
 	}
 	return err
 }