diff --git a/fs/exec.c b/fs/exec.c
index 34e6a2e53268..b3e87bd50962 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1573,6 +1573,12 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 	if (task_no_new_privs(current))
 		bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
 
+	/*
+	 * If another task is sharing our fs, we cannot safely
+	 * suid exec because the differently privileged task
+	 * will be able to manipulate the current directory, etc.
+	 * It would be nice to force an unshare instead...
+	 */
 	t = p;
 	n_fs = 1;
 	spin_lock(&p->fs->lock);
@@ -1753,6 +1759,7 @@ static int search_binary_handler(struct linux_binprm *bprm)
 	return retval;
 }
 
+/* binfmt handlers will call back into begin_new_exec() on success. */
 static int exec_binprm(struct linux_binprm *bprm)
 {
 	pid_t old_pid, old_vpid;
@@ -1811,6 +1818,11 @@ static int bprm_execve(struct linux_binprm *bprm,
 	if (retval)
 		return retval;
 
+	/*
+	 * Check for unsafe execution states before exec_binprm(), which
+	 * will call back into begin_new_exec(), into bprm_creds_from_file(),
+	 * where setuid-ness is evaluated.
+	 */
 	check_unsafe_exec(bprm);
 	current->in_execve = 1;