[PATCH 5.10 123/126] drivers: video: fbcon: fix NULL dereference in fbcon_cursor()

[Greg Kroah-Hartman]

From: Du Cheng <ducheng2@xxxxxxxxx>

commit 01faae5193d6190b7b3aa93dae43f514e866d652 upstream.

add null-check on function pointer before dereference on ops->cursor

Reported-by: syzbot+b67aaae8d3a927f68d20@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Du Cheng <ducheng2@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210312081421.452405-1-ducheng2@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/video/fbdev/core/fbcon.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1344,6 +1344,9 @@ static void fbcon_cursor(struct vc_data
 
 	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
 
+	if (!ops->cursor)
+		return;
+
 	ops->cursor(vc, info, mode, get_color(vc, info, c, 1),
 		    get_color(vc, info, c, 0));
 }