Race condition hangs on multiple mintty/tcsh? Brad Wetmore

[Kevin Schnitzius]

On Wednesday, August 5, 2020, 06:56:48 PM EDT, Thomas Wolff <towo@towo.net> wrote: 
>Am 04.08.2020 um 12:02 schrieb Thomas Wolff:
>> Am 04.08.2020 um 00:13 schrieb Brad Wetmore via Cygwin:
>>> Hi,
>>>
>>> I generally kick off multiple (10) mintty sessions, and place them 
>>> around the screen.
>>>
>>> C:/cygwin64/bin/mintty.exe -i /Cygwin-Terminal.ico \
>> --position @3 --position 120,0 --size 80x71 /bin/tcsh &
>>> C:/cygwin64/bin/mintty.exe -i /Cygwin-Terminal.ico \
>>> --position @3 --position 715,0 --size 80x45 /bin/tcsh &
>>> C:/cygwin64/bin/mintty.exe -i /Cygwin-Terminal.ico \
>>> --position @3 --position 715,660 --size 80x24 /bin/tcsh &
>>>
>>> Within the last 6 months or so, about 2-3 of them would hang and 
>>> either mintty/tcsh would not start. I put a "sleep 1" in between each 
>>> invocation and that seemed to take care of it.
>>>
>>> With the latest cygwin update, about 8 of them just hang even with 
>>> the sleep 1. I put in a "sleep 2", and now everything is coming up 
>>> again.
>>>
>>> Not sure if this is a mintty or tcsh issue, but just wondering if 
>>> others are seeing this before I start trying to debug this.
>> I can reproduce such behaviour with /bin/bash (easy cross-check), and 
>> in fact the shell is running in that case (easy test via `echo > 
>> .log`), so I have a vague and unpleasant suspicion it might in fact be 
>> related to mintty although I have no idea how that would happen. To be 
>> analysed.
> When in this state, on the pty from which mintty receives child process 
> output, select() does not report a ready for reading condition; could it 
> be related to the recent poll/select patch? I could not reproduce it in 
> cygwin 3.0.7.

for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ; do mintty  -i /Cygwin-Terminal.ico  --position @3 --position 120,$i --size 80x24 /bin/bash & done

This does not fail for me.  Nor does it fail from cmd or powershell using a script.

I tried 3.1.4 and 3.1.6 on Windows 10.  I tried up to 100 instances of of mintty...


Kevin