linux-kernel - [PATCH] tty: vt: keyboard: fix general protection fault in k

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Message-Id: <20260207192708.44188-1-officialsohamkute@gmail.com>
Date: Sun,  8 Feb 2026 00:57:08 +0530
From: Soham Kute <officialsohamkute@...il.com>
To: gregkh@...uxfoundation.org,
	jirislaby@...nel.org
Cc: linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Soham Kute <officialsohamkute@...il.com>,
	syzbot+03f79366754268a0f20c@...kaller.appspotmail.com
Subject: [PATCH] tty: vt: keyboard: fix general protection fault in k_meta

syzbot reported a general protection fault in k_meta() caused by
dereferencing an invalid keyboard pointer when checking META mode.

Add a defensive check to ensure the keyboard pointer is valid before
calling vc_kbd_mode().

Reported-by: syzbot+03f79366754268a0f20c@...kaller.appspotmail.com

Signed-off-by: Soham Kute <officialsohamkute@...il.com>
---
 drivers/tty/vt/keyboard.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index d65fc60dd..b535d7a42 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -880,7 +880,7 @@ static void k_meta(struct vc_data *vc, unsigned char value, char up_flag)
 	if (up_flag)
 		return;
 
-	if (vc_kbd_mode(kbd, VC_META)) {
+	if (kbd && vc_kbd_mode(kbd, VC_META)) {
 		put_queue(vc, '\033');
 		put_queue(vc, value);
 	} else
-- 
2.34.1