Index: kernel-rhel7/drivers/tty/n_tty.c

===================================================================

--- kernel-rhel7.orig/drivers/tty/n_tty.c

+++ kernel-rhel7/drivers/tty/n_tty.c

@@ -2128,7 +2128,7 @@ do_it_again:

  *		  lock themselves)

  */

-static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,

+static ssize_t noinline kpatch_n_tty_write(struct tty_struct *tty, struct file *file,

 			   const unsigned char *buf, size_t nr)

 {

 	const unsigned char *b = buf;

@@ -2210,6 +2210,12 @@ break_out:

 	return (b - buf) ? b - buf : retval;

 }

+static ssize_t __attribute__((optimize("-fno-optimize-sibling-calls"))) n_tty_write(struct tty_struct *tty, struct file *file,

+			   const unsigned char *buf, size_t nr)

+{

+	return kpatch_n_tty_write(tty, file, buf, nr);

+}

+

 /**

  *	n_tty_poll		-	poll method for N_TTY

  *	@tty: terminal device