diff --git a/fs/compat.c b/fs/compat.c
index 970888aad843..01f39f87f372 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1913,7 +1913,7 @@ asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds,
 	}
 
 	if (sigmask) {
-		if (sigsetsize |= sizeof(compat_sigset_t))
+		if (sigsetsize != sizeof(compat_sigset_t))
 			return -EINVAL;
 		if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
 			return -EFAULT;