linux-kernel - [PATCH] drivers: tty: vt: vt.c: fix NULL dereference crash

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Date:   Sun,  7 Mar 2021 12:56:43 +0200
From:   Hassan Shahbazi <h.shahbazi.git@...il.com>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org,
        Hassan Shahbazi <h.shahbazi.git@...il.com>
Subject: [PATCH] drivers: tty: vt: vt.c: fix NULL dereference crash

Fix a NULL deference crash on hiding the cursor.

Reported by: syzbot
https://syzkaller.appspot.com/bug?id=defb47bf56e1c14d5687280c7bb91ce7b608b94b

Signed-off-by: Hassan Shahbazi <h.shahbazi.git@...il.com>
---
 drivers/tty/vt/vt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 284b07224c55..8c3e83c81341 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -904,7 +904,9 @@ static void hide_cursor(struct vc_data *vc)
 	if (vc_is_sel(vc))
 		clear_selection();
 
-	vc->vc_sw->con_cursor(vc, CM_ERASE);
+	if (vc->vc_sw)
+		vc->vc_sw->con_cursor(vc, CM_ERASE);
+
 	hide_softcursor(vc);
 }
 
-- 
2.26.2