Cygwin fork failure

David Svoboda svoboda@cs.cmu.edu
Wed Nov 23 21:06:00 GMT 2005


Larry Hall (Cygwin) wrote:

> svoboda@cs.cmu.edu wrote:
>
>> On Saturday 19 November 2005 01:07 am, Larry Hall (Cygwin) wrote:
>>
>>> David Svoboda wrote:
>>>
>>>> I have built a C++ server program called 'analyzer'. But when I try to
>>>> run it, it fails upon trying to execute a 'fork' command. Why?
>>>
>
>
> <snip>
>
>
>>>
>>> If running 'rebaseall' doesn't help (see the README) and 'analyzer' 
>>> doesn't
>>> use any DLLs that were built as part of that package (in which case you
>>> need to tell 'rebaseall' about them), then try:
>>>
>>> <http://sources.redhat.com/ml/cygwin/2005-09/msg00945.html>
>>
>>
>>
>> Thanks for the response. The 'analyzer' program is statically linked; 
>> it involves no DLLs. Rebaseall did nothing. And increasing the size 
>> of the heaps did nothing (I tried 2x, 4x, 8x and 16x). My machine is 
>> totally wedged now...even safe mode doesn't work.
>>
>> I can only say that this fork problem happens on several other 
>> Windows machines at our university, but it does not seem to happen to 
>> machines not at the university. Furthermore this fork problem now 
>> affects previous versions of my 'analyzer' software...last week's 
>> version worked then, but does not now. It's as if  Satan put a curse 
>> on all the PCs only at this university.
>>
>> Any other suggestions?
>
>
>
> Trying a snapshot it a good subsequent step.  If you're going to be 
> building
> things against Cygwin, you'll want to pull the cygwin-inst.  
> Otherwise, cygwin1-*.dll is enough and is probably plenty for starters.
>
>
> <http://cygwin.com/snapshots/>
>
>
Well, the latest snapshot available is 2005-Nov-17. Planting its
cygwin1.dll into cygwin/bin generates the following result:

    analyzer --KANTOO_LANGUAGE=halo --ANALYZER_PORT=4052 
-server-multiple -fork
    Analyzer 2.0; DMK 0.2 (HALO); DOMO 0.2 (KCE)
          6 [main] analyzer 2164 
fhandler_disk_file::fixup_mmap_after_fork: requested 0x18730000 != 0x0 
mem alloc base 0x18730000, state 0x1000, size 4096, Win32 error 487
    d:\svoboda\kantoo\bin\analyzer (2164): *** 
recreate_mmaps_after_fork_failed
    ]0;~
    svoboda@quebec ~
    $

which is a slight improvement over the previous result:

    svoboda@quebec ~
    $ analyzer --KANTOO_LANGUAGE=halo --ANALYZER_PORT=4052 
-server-multiple -fork
    Analyzer 2.0; DMK 0.2 (HALO); DOMO 0.2 (KCE)
          6 [main] analyzer 224 
fhandler_disk_file::fixup_mmap_after_fork: requested 0x18730000 != 0x0 
mem alloc base 0x18730000, state 0x1000, size 4096, Win32 error 487
    d:\svoboda\kantoo\bin\analyzer (224): *** 
recreate_mmaps_after_fork_failed
         11 [main] analyzer 1136 fork_parent: child 224 died waiting for 
dll loading
    Failed to fork properly!
    ]0;~
    svoboda@quebec ~
    $

but still crashes my analyzer.

My best guess is that this bug was introduced by a new version of
cygwin, as it did not occur until I did a cygwin-update.

It seems that the oldest cygwin I can get is 1.5.17.1, (1.5.18.1 being 
the current version) Is there any way to get older c ygwins?
~Dave


~Dave


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