Re: [Qemu-devel] qemu vga crash

[address@hidden]

On Tue, May 21, 2019 at 01:52:31PM +0000, Vladimir Sementsov-Ogievskiy wrote:
> Could anybody help?

How about doing your homework properly?

> > Hi Gerd!
> > 
> > Writing to you, as you were the last one who committed to vga_draw_graphic, 
> > hope you can help.
> > 
> > We faced the following crash in 2.12-based Qemu, but code seems not really 
> > changed:

Pretty lame excuse for not testing a more recent release or git master.

And you are wrong.  The code *has* changed,
and the bug has been fixed a year ago already.

commit a89fe6c329799e47aaa1663650f076b28808e186
Author: Gerd Hoffmann <address@hidden>
Date:   Mon May 14 12:31:17 2018 +0200

    vga: catch depth 0
    
    depth == 0 is used to indicate 256 color modes.  Our region calculation
    goes wrong in that case.  So detect that and just take the safe code
    path we already have for the wraparound case.
    
    While being at it also catch depth == 15 (where our region size
    calculation goes wrong too).  And make the comment more verbose,
    explaining what is going on here.
    
    Without this windows guest install might trigger an assert due to trying
    to check dirty bitmap outside the snapshot region.
    
    Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1575541
    Signed-off-by: Gerd Hoffmann <address@hidden>
    Message-id: address@hidden

cheers,
  Gerd