diff --git a/exec.c b/exec.c
index 6be6af1bc4..4d7d97cc8f 100644
--- a/exec.c
+++ b/exec.c
@@ -28,7 +28,7 @@ exec(char *path, char **argv)
   pgdir = 0;
 
   // Check ELF header
-  if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
+  if(readi(ip, (char*)&elf, 0, sizeof(elf)) != sizeof(elf))
     goto bad;
   if(elf.magic != ELF_MAGIC)
     goto bad;