Re: python fails asyncio tests (py 3.7 & 3.8)

[Mark Geisert <mark@maxrnd.com>]

Hi Jim,

Jim Bell wrote:
> On 2020-11-21 5:59 AM, Jim Bell wrote:
>> The standard python asyncio tests hang.
>>
>>         cd /usr/lib/python3.8/test
>>
>>         python3.8 test_asyncore.py -v
>>
>> [...]
> 
> 
> Using strace, stripping down this very repeatable test, and grabbing the 
> source-code snapshot, it looks like winsup/cygwin/select.cc socket_cleanup() is 
> waiting forever for the thread to go away.
> 
> strace:
> 
>    121 6732185 [main] python3.8 13329 select_stuff::cleanup: calling cleanup rout
> ines
>    178 6732363 [main] python3.8 13329 socket_cleanup: si 0x800290E10 si->thread 0
> x18023E758
> -
> 
> But I don't see the select_printf("returning")  at select.cc:1808, so the 
> si->thread->detach() call seems to be blocked forever.  I don't see that we make 
> it here either:
> 
>      select.cc:1685  select_printf ("leaving thread_socket");
> 
> I see a bool stop_thread field in select_info, inherited by select_socket_info 
> (select.h), used by other mechanisms. Seems that could be set by socket_cleanup() 
> and used by thread_socket() to break out of its event loops (select.cc lines 1660  
> and 1667)
> 
> https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/select.cc;hb=HEAD#l1796 

Thanks for the report and especially for the initial debugging you've done.  I've 
reproduced the issue on my test machine.  No need to supply 'cygcheck -svr' at 
this point.  I'll investigate this further and keep you posted (on the Cygwin 
mailing list).

..mark