[ros-dev] Re: [ros-svn] [ion] 16728: - Don't try to get the length of a possibly empty string. This fixes many menu applications (such as WinRAR). However I'm now getting a bug due to a double-free. It seems a GDI Object is being freed twice. Can anyone check this out please?

[Alex Ionescu]

ion at svn.reactos.com wrote:

> - Don't try to get the length of a possibly empty string. This fixes many menu applications (such as WinRAR). However I'm now getting a bug due to a double-free. It seems a GDI Object is being freed twice. Can anyone check this out please?
>
>  
>
With the combination of this patch + Hartmut's patch + DBG = 0 build 
(and/or disabling RZ detection), Winrar runs fine again. However, 
pressing OK in the dialog bug causes a crash in 
RtlFreeUnicodeString->RtlpFreeMemory->ExFreePool. It seems the buffer is 
invalid. So it looks like two things have to be fixed for Winrar and 
other apps to work fine (Windows Commander does work now):

1) Stop the GDI Object from being freed twice. This will fix the first 
bugcheck and allow Winrar to work in DBG = 1 with RZ enabled. Disabling 
RZ is only a hack and shouldn't be used a solution. The stack trace 
ships the double-free routine pretty well, but I'm not well versed in 
win32k to fix this.

2) Find out why we are RtlFreeUnicodestring-ing what seems to be an 
invalid pointer.

I think if we can fix these two issues we'll have many more apps working 
again!
I've tested Winrar 3.50 b7, btw.

Best regards,
Alex Ionescu