diff --git a/libc/kernel/uapi/linux/kexec.h b/libc/kernel/uapi/linux/kexec.h
index 2e3bd0c..7dbc87e 100644
--- a/libc/kernel/uapi/linux/kexec.h
+++ b/libc/kernel/uapi/linux/kexec.h
@@ -43,8 +43,8 @@
 #define KEXEC_SEGMENT_MAX 16
 struct kexec_segment {
   const void * buf;
-  size_t bufsz;
+  __kernel_size_t bufsz;
   const void * mem;
-  size_t memsz;
+  __kernel_size_t memsz;
 };
 #endif