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From: Ken Brown <kbrown@cornell.edu>
To: "cygwin@cygwin.com" <cygwin@cygwin.com>
Subject: Re: fork: Resource temporarily unavailable errors after upgrading cygwin packages
Date: Thu, 2 Jan 2020 03:02:19 +0000
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On 1/1/2020 6:43 PM, David Finnie wrote:
> That strongly implies that there is an issue with changes made since then. I 
> noticed that in fork.cc, at line 540, this new code exists:
> 
>    /* Do not attach to the child before it has successfully initialized.
>       Otherwise we may wait forever, or deliver an orphan SIGCHILD. */
>    if (!child.reattach ())
>      {
>        this_errno = EAGAIN;
> #ifdef DEBUGGING0
>        error ("child reattach failed");
> #endif
>        goto cleanup;
>      }
> 
> Since I am getting "Resource temporarily unavailable", which equates to EAGAIN, 
> and this code is new, this looks like the most likely candidate to investigate 
> first (but rest assured that I'm not saying that this code is definitely the 
> culprit !).

You could try building cygwin with DEBUGGING0 defined to see if this is where 
the EAGAIN is coming from.  I think the error message would show up in strace 
output, so you'd have to be able to reproduce the problem under strace.

And it would be great if you could find a testcase that you can share with the 
list, so that others can try to reproduce the problem.

Ken

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