[04/26] tty: kbd: reduce stack size with KASAN

Commit Message

Arnd Bergmann March 2, 2017, 4:38 p.m. UTC

As reported by kernelci, some functions in the VT code use significant
amounts of kernel stack when local variables get inlined into the caller
multiple times:

drivers/tty/vt/keyboard.c: In function 'kbd_keycode':
drivers/tty/vt/keyboard.c:1452:1: error: the frame size of 2240 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Annotating those functions as noinline_for_kasan prevents the inlining
and reduces the overall stack usage in this driver.

Signed-off-by: Arnd Bergmann <[e-mail]>
---
 drivers/tty/vt/keyboard.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 397e1509fe51..f8a183c1639f 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -300,13 +300,13 @@  int kbd_rate(struct kbd_repeat *rpt)
 /*
  * Helper Functions.
  */
-static void put_queue(struct vc_data *vc, int ch)
+static noinline_for_kasan void put_queue(struct vc_data *vc, int ch)
 {
 	tty_insert_flip_char(&vc->port, ch, 0);
 	tty_schedule_flip(&vc->port);
 }
 
-static void puts_queue(struct vc_data *vc, char *cp)
+static noinline_for_kasan void puts_queue(struct vc_data *vc, char *cp)
 {
 	while (*cp) {
 		tty_insert_flip_char(&vc->port, *cp, 0);
@@ -554,7 +554,7 @@  static void fn_inc_console(struct vc_data *vc)
 	set_console(i);
 }
 
-static void fn_send_intr(struct vc_data *vc)
+static noinline_for_kasan void fn_send_intr(struct vc_data *vc)
 {
 	tty_insert_flip_char(&vc->port, 0, TTY_BREAK);
 	tty_schedule_flip(&vc->port);