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Re: Odd hang in python waiting for child; strace wakes hung process?




On 2018-03-21 16:07, Dan Kegel wrote:
> On Wed, Mar 21, 2018 at 11:54 AM, Achim Gratz <Stromeko@xxxxxxxx> wrote:
>> Well, with the sporadic hanging/defunct processes at work my routine is
>> to send CONT to all Cygwin processes, then HUP/KILL to anything that's
>> still not live or gone and then another round of CONT.  This works
>> _most_ of the time, anything more stubborn I /bin/kill -f usually.
> 
> Since I wrote, both bots hung again.  This time I verified:
> 0) both had the defunct git process as expected
> 1) kill -CONT the-pid doesn't do anything, nor does kill -9.  It's truly wedged.
> 2) the process stays in its spin hang until you ^C strace -p the-pid
> 3) ^C-ing the strace causes the process to terminate (strace alone doesn't)
> 4) taskkill /pid the-task /f also kills the process successfully.
> 
> So I could write a script that watched for defunct git processes
> and taskkilled their parent.  Build jobs would fail, but at least
> the bot would stay up.  Of course it would be much nicer if
> the cygwin python process didn't get wedged.
> 
> Alternately, I suppose I could try running native python...
> or cygwin's python3... but dangit, kill -9 should work.

Seems to be looping on access failure to a Windows mailslot; not sure what this
feature is normally used for: dmesg/syslog messages/AF_UNIX sockets?

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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