Re: Intermittent failures retrieving process exit codes

[Tom Honermann <thonermann@coverity.com>]

On 11/15/2013 01:53 PM, Denis Excoffier wrote:
> On 2013-11-14 05:01, Tom Honermann wrote:
>> On 12/21/2012 01:30 AM, Tom Honermann wrote:
>>>
>>> The workaround I implemented within Cygwin was simple and sloppy.  I
>>> added a call to Sleep(1000) immediately before the call to ExitThread()
>>> in wait_sig() in winsup/cygwin/sigproc.cc.  Since this thread (probably)
>>> doesn't exit until the process is exiting anyway, the call to Sleep()
>>> does not adversely affect shutdown.  The thread just gets terminated
>>> while in the call to Sleep() instead of exiting before the process is
>>> terminated or getting terminated while still in the call to
>>> ExitThread().  A better solution might be to avoid the thread exiting at
>>> all (so long as it can't get terminated while holding critical
>>> resources), or to have the process exiting thread wait on it.  Neither
>>> of these is ideal.  Orderly shutdown of multi-threaded processes is
>>> really hard to do correctly on Windows.
>
> I experience on Windows 7 (not on XP) some problems that may be related.
> I would like to test your workaround, but sigproc.cc has much changed since
> then, there is now an exit_thead function with the comment "Exit the current
> thread very carefully.". I tried to insert Sleep(1000) at the end of
> exit_thread, immediately before "ExitThread (0)", but this yielded no
> change at all.
>
> Could someone be kind enough to update the workaround for modern sigproc.cc?

Hi Denis.  Cygwin versions 1.7.18 and later contain a workaround for 
this issue.  If you are running something older than that, I highly 
encourage you to upgrade.  Many stability related fixes have been made 
in more recent versions.

> Very briefly, my problem is that when i "tar xf —use-compress-program=xz", i
> get:
> tar: Unexpected EOF in archive
> tar: Unexpected EOF in archive
> tar: Error is not recoverable: exiting now
> and the last file of the archive is truncated at some 512bytes block. This
> occurs on Windows 7 (not on XP); with xz-5.1.3alpha (not with xz-5.1.2alpha or
> xz-5.0.5); never on most tar.xz files; almost always on some (rare) tar.xz files
> (one notable example is bc-1.06.95.tar.bz2 bunzip2Â’ed and then xzÂ’ed); depends
> on the .tar file itself, not on the option (like -9e, -0) used to create the
> .tar.xz; never with "tar tf"; and with all tarÂ’s i have tested. The return code
> of all the involved xz -d commands is always zero though. Perhaps after all, this
> is unrelated?

This doesn't sound related to the intermittent incorrect exit code 
defect to me.  I'm afraid I don't have other explanations for what you 
are experiencing though.

Tom.

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