diff --git a/src/stub/src/amd64-darwin.macho-entry.S b/src/stub/src/amd64-darwin.macho-entry.S
index f937caf1..93931402 100644
--- a/src/stub/src/amd64-darwin.macho-entry.S
+++ b/src/stub/src/amd64-darwin.macho-entry.S
@@ -313,7 +313,7 @@ is_pie:
         movq %rsi,%arg1  // src
         pop %arg2  // P_14  srclen
         call *%rbp  // old f_exp
-        pop %ecx  // P_13  toss .sz_unc
+        pop %rcx  // P_13  toss .sz_unc
 
 // PROT_EXEC
         pop %arg2  // P_12  length
diff --git a/src/stub/src/amd64-linux.elf-entry.S b/src/stub/src/amd64-linux.elf-entry.S
index 888720de..eb6cafbc 100644
--- a/src/stub/src/amd64-linux.elf-entry.S
+++ b/src/stub/src/amd64-linux.elf-entry.S
@@ -285,7 +285,7 @@ unfold:  // IN: rbp= &f_exp; rsp/ &proc_self_exe,%entry
         movq %rsi,%arg1  // src
         pop %arg2  // P_14  srclen
         call *%rbp  // old f_exp
-        pop %ecx  // P_13  toss .sz_unc
+        pop %rcx  // P_13  toss .sz_unc
 
 // PROT_EXEC
         pop %arg2  // P_12  length