--- linux-cjktty-5.4.53.patch	2020-08-08 17:16:04.000000000 +0800
+++ linux-cjktty-5.4.54.patch	2020-08-08 23:18:35.000000000 +0800
@@ -111,11 +111,11 @@
  		notify_update(vc);
  	}
 @@ -1095,7 +1118,7 @@ int vc_allocate(unsigned int currcons)	/* return 0 on success */
- 	if (!*vc->vc_uni_pagedir_loc)
- 		con_set_default_unimap(vc);
- 
+ 	    vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
+ 		goto err_free;
+ 	err = -ENOMEM;
 -	vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
-+	vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size * 2, GFP_KERNEL);
++	vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size * 2, GFP_KERNEL);
  	if (!vc->vc_screenbuf)
  		goto err_free;
  
@@ -137,11 +137,11 @@
  	if (new_cols == vc->vc_cols && new_rows == vc->vc_rows)
  		return 0;
  
- 	if (new_screen_size > KMALLOC_MAX_SIZE)
+ 	if (new_screen_size > KMALLOC_MAX_SIZE || !new_screen_size)
  		return -EINVAL;
 -	newscreen = kzalloc(new_screen_size, GFP_USER);
 +
-+	newscreen = kmalloc(new_screen_size * 2, GFP_USER);
++	newscreen = kzalloc(new_screen_size * 2, GFP_USER);
 +
  	if (!newscreen)
  		return -ENOMEM;
@@ -245,9 +245,9 @@
  				inverse = 0;
  				width = 1;
 @@ -3360,7 +3413,7 @@ static int __init con_init(void)
- 		INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
  		tty_port_init(&vc->port);
  		visual_init(vc, currcons, 1);
+ 		/* Assuming vc->vc_{cols,rows,screenbuf_size} are sane here. */
 -		vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
 +		vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size * 2, GFP_NOWAIT);
  		vc_init(vc, vc->vc_rows, vc->vc_cols,