On 2/13/2011 11:24 AM, Corinna Vinschen wrote:
On Feb 12 19:12, Corinna Vinschen wrote:
On Feb 12 17:44, Corinna Vinschen wrote:
On Feb 12 10:31, Ken Brown wrote:
I just did a system restore to undo the last round of Windows
updates, and the problem went away. I'm not sure where to go from
here.
You're right, I can reproduce it on W7 32 and 64 bit.
[...]
By installing the security updates again, one by one, I figure out
that it is the security update connected to KB 2393802 which triggers
the problem.
[...]
Just FYI, I have a working workaround. It's not exactly how I would
like to handle this stuff, but at least we know there *is* a solution
which still maintains the desired ability to delete an in-use directory.
Ok, I think I have a solution now.
A few hours of debugging turned up that the KB 2393802 patch introduces
a change to the layout of the (undocumented) structure in which Windows
stores the CWD starting with Vista. That's the structure we called
FAST_CWD in Cygwin. The new layout is sufficiently different that
Cygwin scrambled the contents of the structure from the Win32
perspective.
Above all, the new structure layout is 4 bytes bigger, because
RtlSetCurrentDirectory_U now also stores some filesystem flags which
RtlGetCurrentDirectory_U uses to find out if the CWD is on a removable
device, and if that device is still available.
If Cygwin scrambled the content effectivly enough, Win32 calls like
CreateProcess could become so confused that they potentially crash with
a SEGV.
I just checked in a patch to Cygwin which uses the new structure layout
on systems which already have the KB 2393802 patch installed and the old
structure layout otherwise.
I also uploaded a new Cygwin snapshot to http://cygwin.com/snapshots/
Please give the today's snapsot a try. I tested it on Windows 2008 32
bit as well as on W7 32 and 64 bit, with and without KB 2393802
installed. "It works for me."(TM)
Works for me on W7 64 bit with KB 2393802 installed. (I didn't test
without it. I had already reinstalled the updates.)
Thanks.
Ken
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