Error in GDI (StretchBlt) - proper fix?

[David Gümbel]

Hello everybody,


I am debugging an application and got up to the point where I have reason to 
believe that the StretchBlt function in GDI is part of the problem. A 
backtrace of the exception I always run into looks like this:

err:syslevel:_CheckNotSysLevel Holding lock 0x7ecd0820 level 3
wine: Unhandled exception 0x80000003 at address 0x0000:0x7ee96b34 (thread 
0011), starting debugger...
WineDbg starting on pid 0x10
err:syslevel:_CheckNotSysLevel Holding lock 0x7ecd0820 level 3
0x7ee96b35 _CheckNotSysLevel+0x3d in kernel32: addl     $36,%esp
Wine-dbg>bt
Backtrace:
=>1 0x7ee96b35 _CheckNotSysLevel+0x3d in kernel32 (0x7ee96b35)
  2 0x7ec84c81 GDI_CheckNotLock+0x20 in gdi32 (0x7ec84c81)
  3 0x7ec628e8 DeleteDC+0x26 in gdi32 (0x7ec628e8)
  4 0x7ec6420b GetDIBits+0x1fd in gdi32 (0x7ec6420b)
  5 0x7ec6c282 in gdi32 (+0x2c282) (0x7ec6c282)
  6 0x7ec5bfee StretchBlt+0xca in gdi32 (0x7ec5bfee)
  7 0x0042a3aa in bav (+0x2a3aa) (0x0042a3aa)
  8 0x00425460 in bav (+0x25460) (0x00425460)
  9 0x005d1304 in bav (+0x1d1304) (0x005d1304)
  10 0x005e4f5d in bav (+0x1e4f5d) (0x005e4f5d)
  11 0x0066f10b in bav (+0x26f10b) (0x0066f10b)
  12 0x00681f8b in bav (+0x281f8b) (0x00681f8b)
  13 0x7ee7ff5f in kernel32 (+0x4ff5f) (0x7ee7ff5f)
  14 0xb7e9d387 wine_switch_to_stack+0x17 in libwine.so.1 (0xb7e9d387)



When looking at StretchBlt's source code, I see a comment saying that there 
is a race condition in this function[1]. If I'm not mistaken, this problem 
has been reported in january as bug #4284, causing trouble (a deadlock) with 
MS PowerPoint[2]. Walt Ogburn suggested in january that commenting out 
#define STRETCH_VIA_DIB in dlls/gdi/mfdrv/bitblt.c could work around the 
problem[3].

Does anybody have any idea on how a proper fix for that function might 
approximately look like?


Thanks,



David


[1] http://source.winehq.org/source/dlls/gdi/bitblt.c#L139
[2] http://bugs.winehq.com/show_bug.cgi?id=4284
[3] http://www.winehq.org/pipermail/wine-devel/2006-January/044040.html