On 2022-03-15 Jia Tan wrote: > As promised, I have attached a patch to solve the problem. Instead of > doing as I had originally proposed, I simply added a wake up signal > to a sleeping thread if partial updates are enabled. When the worker > wakes up, it checks if no more input > is available and signals to the main thread if it has output ready > before going back > to sleep. This prevents the deadlock on my liblzma tests and testing > xz with/without timeout.
Thanks to both of you for debugging this. I see now that I had completely missed this corner case. The patch looks correct except that the mutex locking order is wrong which can cause a new deadlock. If both thr->mutex and coder->mutex are locked at the same time, coder->mutex must be locked first. About memlimit updates, that may indeed need some work but I don't know yet how much is worth the trouble. stream_decoder_mt_memconfig() has a few FIXMEs too, maybe they don't need to be changed but it needs to be decided. I'm in a hurry now but I should have time for xz next week. :-) -- Lasse Collin
