On 11/5/20 7:06 AM, Pavel Begunkov wrote: > If there is a long-standing request of one task locking up execution of > deferred requests, and the defer list contains requests of another task > (all files-less), then a potential execution of __io_uring_task_cancel() > by that another task will sleep until that first long-standing request > completion, and that may take long. > > E.g. > tsk1: req1/read(empty_pipe) -> tsk2: req(DRAIN) > Then __io_uring_task_cancel(tsk2) waits for req1 completion. > > It seems we even can manufacture a complicated case with many tasks > sharing many rings that can lock them forever. > > Cancel deferred requests for __io_uring_task_cancel() as well. Thanks, applied. -- Jens Axboe
