Subject: bug#37756: [PATCH] Wrong initialization of fringe bitmap

From: Eli Zaretskii <[email-masked]>
Date: Tue, 15 Oct 2019 12:47:26 +0300

> From: Carlos Pita <[email-masked]>
> Date: Mon, 14 Oct 2019 23:39:19 -0300
> 
> In fringe.c:1606 you have:
> 
>   xfb = xmalloc (sizeof fb + fb.height * BYTES_PER_BITMAP_ROW);
>   fb.bits = b = ((unsigned short *)
> ptr_bounds_clip (xfb + 1, fb.height * BYTES_PER_BITMAP_ROW));
>   xfb = ptr_bounds_clip (xfb, sizeof *xfb);
>   memset (b, 0, fb.height);
> 
> I might be wrong but it seems to me that the last line should be:
> 
>   memset (b, 0, fb.height * BYTES_PER_BITMAP_ROW);
> 
> instead.

Can you explain your reasoning?  The loop after that does initialize
the structure as needed, doesn't it?