diff -Nupr src.orig/drivers/tty/n_tty.c src/drivers/tty/n_tty.c --- src.orig/drivers/tty/n_tty.c 2020-03-10 10:35:54.135564709 -0400 +++ src/drivers/tty/n_tty.c 2020-03-10 10:37:16.551389787 -0400 @@ -2175,7 +2175,7 @@ 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; @@ -2264,6 +2264,12 @@ 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