diff --git a/libc/arch-x86/syscalls/sendfile64.S b/libc/arch-x86/syscalls/sendfile64.S
index 7032e8a..383c8c6 100644
--- a/libc/arch-x86/syscalls/sendfile64.S
+++ b/libc/arch-x86/syscalls/sendfile64.S
@@ -7,6 +7,11 @@
     pushl   %ecx
     pushl   %edx
     pushl   %esi
+    .cfi_def_cfa_offset 16
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
+    .cfi_rel_offset edx, 8
+    .cfi_rel_offset esi, 12
     mov     20(%esp), %ebx
     mov     24(%esp), %ecx
     mov     28(%esp), %edx