Re: [FIX] Re: 2.5.66 new fbcon oops while loading X

On Tue, Mar 25, 2003 at 05:23:07PM +0000, James Simmons wrote:

quoted

quoted

While loading X, I get this oops. The weird thing is that I don't use
framebuffer. I compiled with gcc 3.2.2 but the code generated looks weird.
Virgin gcc 3.2.2 on a pentium III.

You don't use framebuffer? Can you send me your config. 

Ok, I've found the bug, it is in fb_open() in drivers/video/fbmem.c, it
needs this addition:

        if(fbidx >= FB_MAX)
                return -ENODEV;

Without it, large minor numbers result in access beyond the end of
registered_fb.

On Debian, ls /dev/fb[67] results in:
crw--w--w-    1 root     tty       29, 192 Nov 30  2000 /dev/fb6
crw--w--w-    1 root     tty       29, 224 Nov 30  2000 /dev/fb7

On Red Hat this is: 
crw-------    1 root     root      29,   7 Apr 11  2002 /dev/fb7
crw-------    1 root     root      29,   8 Apr 11  2002 /dev/fb8

Which explains why many don't see this bug.

Ah. That explains it. I will apply the fix.

On Wed, 26 Mar 2003, James Simmons wrote:

quoted

On Tue, Mar 25, 2003 at 05:23:07PM +0000, James Simmons wrote:

quoted

quoted

While loading X, I get this oops. The weird thing is that I don't use
framebuffer. I compiled with gcc 3.2.2 but the code generated looks weird.
Virgin gcc 3.2.2 on a pentium III.

You don't use framebuffer? Can you send me your config. 

Ok, I've found the bug, it is in fb_open() in drivers/video/fbmem.c, it
needs this addition:

        if(fbidx >= FB_MAX)
                return -ENODEV;

Without it, large minor numbers result in access beyond the end of
registered_fb.

On Debian, ls /dev/fb[67] results in:
crw--w--w-    1 root     tty       29, 192 Nov 30  2000 /dev/fb6
crw--w--w-    1 root     tty       29, 224 Nov 30  2000 /dev/fb7

On Red Hat this is: 
crw-------    1 root     root      29,   7 Apr 11  2002 /dev/fb7
crw-------    1 root     root      29,   8 Apr 11  2002 /dev/fb8

Which explains why many don't see this bug.

Ah. That explains it. I will apply the fix.

Note that Debian seems to use the old numbering that was obsoleted in 2.4.0.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



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