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Date: Sun, 17 Mar 2024 19:21:16 +0900
To: cygwin@cygwin.com
Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Subject: Re: Bogus exit code 127 from a child process
Message-Id: <20240317192116.b00f24c9ee065f16d6ac6673@nifty.ne.jp>
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From: Takashi Yano via Cygwin <cygwin@cygwin.com>
Reply-To: Takashi Yano <takashi.yano@nifty.ne.jp>
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On Sun, 17 Mar 2024 13:03:40 +0300
Alexey Izbyshev wrote:
> On 2024-03-17 12:27, Takashi Yano wrote:
> > On Sun, 17 Mar 2024 12:01:55 +0300
> > Alexey Izbyshev wrote:
> >> On 2024-03-17 11:44, Takashi Yano wrote:
> >> > On Sun, 17 Mar 2024 11:14:16 +0300
> >> > Alexey Izbyshev wrote:
> >> >> Hello,
> >> >>
> >> >> I've been getting occasional "Error 127" from make -jN on seemingly
> >> >> random jobs. After reducing the set of jobs and eventually eliminating
> >> >> make, I've arrived to this one-liner:
> >> >>
> >> >> bash -c 'true & true & wait -n || echo 1: $? && wait -n || echo 2: $?'
> >> >>
> >> >> When run repeatedly, the second "wait -n" often reports 127.
> >> >>
> >> >> I've reproduced this in the following environments:
> >> >>
> >> >> * Cygwin 3.5.1, Windows 10 22H2 x64
> >> >> * Cygwin 3.4.6, Windows 10 22H2 x64 and Windows 7 x64
> >> >>
> >> >> I couldn't reproduce it in Cygwin 3.3.6 (WOW64) on Windows 7 x64.
> >> >
> >> > Could you please try latest cygwin 3.6.0 (TEST) ?
> >> 
> >> Tested with 3.6.0-0.82.gfc691d0246b9 on Windows 10 22H2 x64, the 
> >> problem
> >> still occurs.
> > 
> > In my evrironmen, trial for 1 hour does not reproduce the issue.
> > Could you please let us know your environment, i.e. CPU, amount of
> > memory, and so on?
> 
> It's been reproduced in a variety of environments:
> 
> * Windows 10 22H2 x64, Intel Core i7 11700, 32 GB RAM
> * Windows 10 22H2 x64, Intel Core i7 9700, 32 GB RAM
> * Windows 10 22H2 x64, Intel Core i7 6700, 32 GB RAM
> * Windows 7 SP1 x64, Intel Core i7 6700, 32 GB RAM
> 
> I'm surprised that you're not hitting it very quickly. The following 
> loop usually fails after a few iterations (rarely a hundred or so) in my 
> tests:
> 
> while bash -c 'true & true & wait -n || { echo 1: $?; exit 1; } && wait 
> -n || { echo 2: $?; exit 1; }'; do echo $((i++)); done

Thanks. My main PC still runs the above test for more than 15000 counts.
So, I tried another PC which CPU is Core i5 540M and could reproduce
the issue about 1 time per a few hundreds count.

I also tried to run sleep 0.1 instead of true, then, the issue happens
1 time per a few decades counts.

I'll look into this problem. Thanks for the report.

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>

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