Re: 1.7.29-2: Exception from cygwin_gethostname

[Ken Brown <kbrown@cornell.edu>]

On 4/10/2014 5:15 AM, Corinna Vinschen wrote:
> Hi David,
> Hi Ken [in CC],
>
> On Apr  7 13:50, David Rothenberger wrote:
>> Larry Hall (Cygwin) wrote:
>>> On 4/7/2014 3:09 PM, Corinna Vinschen wrote:
>>>> On Apr  7 11:49, David Rothenberger wrote:
>>>>> I'm having a problem doing hostname resolution on one of my Windows
>>>>> 7 64 machines after updating cygwin to 1.7.29-2. I first noticed it
>>>>> with ssh. I get an error whenever I try to ssh to any machine using
>>>>> a hostname; it complains the hostname cannot be resolved.
>>>>>
>>>>> An strace of ssh shows an exception occuring right after the call to
>>>>> cygwin_gethostname is logged.
>>>>>
>>>>>      96   58624 [main] ssh 3536 cygwin_gethostname: name daver-pc
>>>>> --- Process 3536, exception 000006ba at 000007FEFDD4940D
>>>>>     860   59484 [main] ssh 3536 __set_errno: void san::leave():315
>>>>> setting errno 14
>>>>
>>>> Exception 0x6ba is "The RPC server is unavailable".  I have no idea why
>>>> this exception is generated at all on your machine.  Usually this is a
>>>> first-chance exception only, which can be ignored, but this is the first
>>>> time I ever saw this and in the above scenario there's no such exception
>>>> expected, so it doesn't get ignored.
>>>>
>>>> Oh well, it would have been helpful if this had been encountered last
>>>> week :(
>>>
>>> Good point.  David, can you go back to last week and see if you can still
>>> reproduce it? ;-)
>>
>> I wish! There were a few important changes to the system starting last
>> Friday and I dearly wish I could go back to before those changes.
>>
>> On Friday, I accidentally installed OpenCandy, a PUP adware "program". I
>> spent some time on Saturday cleaning that with a host of free malware
>> removals. This removed some registry keys, but I'm pretty sure it was
>> all safe. Pretty sure...
>>
>> Also on Saturday I replaced two old HDDs with SSDs. This made my system
>> a lot faster, but I haven't seen any problems associated with it aside
>> from the OS complaining about not getting a network connection right
>> after it boots. I think this is just because it boots so much faster now.
>>
>> I /should/ have tested the snapshots when the call went out. I wished I
>> did now, because then I would know if this issue was related to any of
>> the problems I had late last week. This is a work machine and we're
>> super-busy, so I was hesitant to experiment with snapshots. But I
>> learned my lesson; I'll be testing snapshots when Chris or Corinna ask
>> for testing from now on, on all my machines.
>
> I have uploaded a new snapshot to http://www.cygwin.com/snapshots/ which
> is supposed to workaround this problem by only handling the very
> exceptions the exception handler was designed to handle at this point.
> Can you please check if this works for you?
>
> Ken, I would also be greatful if you could give this snapshot a try.
> You came up with so fascinating testcases.  I tried running emacs-X11 -Q
> with this new code and it still works(*), so I'm hopeful the workaround
> is ok until we have the ultimate, SEH-based solution (which,
> unfortunately, is rather intrusive and so not done in a breeze).
>
> This only affects 64 bit Cygwin so you don't have to test it on
> 32 bit, in theory.

It works fine for me so far (tested 64 bit only).  I ran all the 
previous testcases with no problems.

Sorry about the fc-cache problem.  Yaakov, any further thoughts on this?

Ken

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