timerfd deadlock

Ken Brown kbrown@cornell.edu
Mon Jun 24 20:16:00 GMT 2019


On 6/11/2019 4:52 AM, Corinna Vinschen wrote:
> On Jun  7 12:10, Ken Brown wrote:
>> While testing some new pipe code, I'm occasionally seeing a timerfd deadlock:
>> The main thread is stuck in timerfd_tracker::dtor at timerfd.cc:354, waiting for
>> the timerfd thread to close; and the timerfd thread is stuck at timerfd.cc:140,
>> waiting to acquire a mutex that's held by timerfd_tracker::dtor.
> 
> Hmm, I had hoped my current code does not have a deadlock situation
> anymore, but I was wrong, apparently.
> 
> Is there any chance to create an STC?

I haven't been able to create an STC.  The deadlock seems to depend on a rare 
timing fluke, and I've only seen it when running a parallel make on a clean 
emacs tree, with my new pipe code installed.

On the other hand, I think I have a simple fix, which I'll send to 
cygwin-patches.  With this patch, I ran the parallel make 15 times without 
getting the deadlock.  After reverting the patch, I got the deadlock on the 4th run.

Ken
 ТÒÐÐ¥&ö&ÆVÒ&W÷'G3¢‡GG¢òö7–wv–âæ6öÒ÷&ö&ÆV×2æ‡FÖÀФd¢‡GG¢òö7–wv–âæ6öÒöfðФFö7VÖVçFF–ö㢇GG¢òö7–wv–âæ6öÒöFö72æ‡FÖÀÐ¥Vç7V'67&–&R–æfó¢‡GG¢òö7–wv–âæ6öÒöÖÂò7Vç7V'67&–&R×6–×ÆPРÐ


More information about the Cygwin mailing list