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Re: cygwin 1.7.0-28: Broken pipe signal broken?
Christopher Faylor <cgf-use-the-mailinglist-please <at> cygwin.com> writes:
> >The parallel make is hit and miss; I've seen make go for quite some time
> >without failures. I'm also seeing occasional failures with gcc -pipe.
> >But it looks like I've finally stumbled on a 100% reproducible testcase,
> >in the m4 testsuite. /home/eblake/m4/build/src/m4 is a self-built m4 from
> >the latest m4.git; when I replace that string with /bin/m4, I don't see
> >the failure, so it might be something added in m4.git since m4 1.4.10b
> >that tickles the behavior; I'm still trying to set up a decent debugging
> >session to catch that. I'll continue trying to trim it down even further,
I tried. But it proved very difficult. Even adding a usleep(0) in the code
made it go away, so I couldn't even figure out how to attach a debugger in time
to see the bug in action; it was definitely a form of data race between writing
data to a pipe and calling exit(), where the mere call to usleep(0) was enough
to avoid the race.
>
> I don't understand how this is a useful test case. I obviously don't
> have the /home/eblake/m4/build/src/m4. I looked on sourceware and there
> is no file there either.
Yes, that file was only on my machine; sorry that I made it so hard for you. I
suppose you could have built your own m4 from scratch from m4.git, but that's
asking too much from a STC.
>
> Have you tried the latest snapshot? I made a grasp-in-the-dark change
> there.
Whatever you did made a difference. Everything I've tried with a self-built
cygwin1.dll with your change has worked without issues, where it was previously
failing, including my (private) m4 build that was showing the problem every
single test run.
--
Eric Blake
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