[PATCH 1/1] TTY Fix NULL pointer error in tty_wakeup

[Frankie Lin]

When calling tty_wakeup and the parameter is NULL,the oops will happen.
The virtual address &tty->flags can not be handled in the kernel space,
while PC goto test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags).

Tested on ARM Machine msm8625.

Signed-off-by: Frankie Lin <frankiefrankie.lin@xxxxxxxxx>
---
 drivers/tty/tty_io.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 05400ac..9c4fb2e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -519,6 +519,11 @@ void tty_wakeup(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld;
 
+	if (!tty) {
+		pr_err("tty is null in function: %s.\n", __func__);
+		return;
+	}
+
 	if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
 		ld = tty_ldisc_ref(tty);
 		if (ld) {
-- 
1.7.9.5

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