lkml.org 
[lkml]   [2004]   [Jun]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [Linux-fbdev-devel] 2.6.7 fbcon: set_con2fb on current console = crash
Date
On Saturday 19 June 2004 17:28, Geert Uytterhoeven wrote:
> On Sat, 19 Jun 2004, Antonino A. Daplas wrote:
> > Thanks. Actually there's still a critical flaw in the set_con2fbmap
> > code. For one, con2fb_map is never initialized. It's just fortunate that
> > this array happens to be filled with zeroes so con2fb_map[n] will always
> > return zero and registered_fb[0] happens to contain a valid info. So it
> > works, by accident.
>
> According to the C standard, global variables are initialized to zero,
> unless specified otherwise.
>

I know, but what I meant was con2fb_map[] is never initialized by fbcon. So
if the first valid fbdev is in registered_fb[1], then con2fbmap must be
initialized to 1's by fbcon. It doesn't. Note, fbdev-2.4 does the
initialization correctly.

So 2 critical flaws in the code:

1. con2fb_map[] is always zero-set
2. fbcon assumes that registered_fb[0] is always valid

Both flaws will manifest by doing this:

modprobe fbdev1 - in registered_fb[0]
modprobe fbdev2 - in registered_fb[1]
rmmod fbdev1 - registered_fb[0] becomes invalid
modprobe fbcon
- con2fb_map[] with zeroes instead of 1's and fbcon_startup looks for
fb_info in registered_fb[0] instead of registered_fb[1]

Tony


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:03    [W:0.107 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site