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On Apr 16 08:17, Jim Reisert AD1C wrote:
> I am unable to start Cywin/X X-server 1.17.1 with this version.
> Previous releases of 2.0.0.x were OK.  I had to revert to 1.7.35-1 for
> the time being.
> Other than updating to, I also installed the April 2015 "Patch
> Tuesday" updates from Microsoft.  I don't know if the two are related.
>   Windows 7 Home Premium, 64-bit
> Exception: STATUS_ACCESS_VIOLATION at eip=77C50F8A
> eax=00000000 ebx=612D67B0 ecx=00001000 edx=612D2648 esi=00000000 edi=0028C790
> ebp=0028C608 esp=0028C604 program=C:\Cygwin\bin\XWin.exe, pid 1660, thread main
> cs=0023 ds=002B es=002B fs=0053 gs=002B ss=002B
> Stack trace:
> Frame     Function  Args
> 0028C608  77C50F8A (00000000, 612D2648, 00000000, 612D67B0)
> 0028C738  610CDA1F (000043FF, 00000000, 00000000, 80012428)
> 0028C7B8  61047198 (00000000, 72483F24, 75604227, 00000254)
> 0028C7F8  610F629D (00000001, 00000000, 00000000, 75623912)

Ohhh...kay.  This looks like a check for equality of two SIDs, the owner
SID and the group SID of a file, crashing while being called from fchown.
This test didn't exist up to 2.0.0-0.4 because it was addded to handle
the owner == group case.  But then again, this would mean that with
older versions the group SID of a file is not set.  Or changed, fwiw.

This might happen if either one of these SIDs is invalid or NULL, which
in turn may occur if the owner or group SID can't be found in the
account DB.

The question is then, is your /etc/passwd or /etc/group file broken,
and/or are you using the "files" only method in /etc/nsswitch.conf?

I could add an extra check which refuses to change permissions if
the account's SID can't be found, but since this occurs very deep
in the call stack, the error message might be pretty vapid.

Alternatively I just let this slip through and you might wonder
why the group hasn't changed in this case.

Btw., it would be nice to know why XWin tries to chown a file.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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