On 3/31/21 5:18 PM, Pavel Begunkov wrote: > [ 491.222908] INFO: task thread-exit:2490 blocked for more than 122 seconds. > [ 491.222957] Call Trace: > [ 491.222967] __schedule+0x36b/0x950 > [ 491.222985] schedule+0x68/0xe0 > [ 491.222994] schedule_timeout+0x209/0x2a0 > [ 491.223003] ? tlb_flush_mmu+0x28/0x140 > [ 491.223013] wait_for_completion+0x8b/0xf0 > [ 491.223023] io_wq_destroy_manager+0x24/0x60 > [ 491.223037] io_wq_put_and_exit+0x18/0x30 > [ 491.223045] io_uring_clean_tctx+0x76/0xa0 > [ 491.223061] __io_uring_files_cancel+0x1b9/0x2e0 > [ 491.223068] ? blk_finish_plug+0x26/0x40 > [ 491.223085] do_exit+0xc0/0xb40 > [ 491.223099] ? syscall_trace_enter.isra.0+0x1a1/0x1e0 > [ 491.223109] __x64_sys_exit+0x1b/0x20 > [ 491.223117] do_syscall_64+0x38/0x50 > [ 491.223131] entry_SYSCALL_64_after_hwframe+0x44/0xae > [ 491.223177] INFO: task iou-mgr-2490:2491 blocked for more than 122 seconds. > [ 491.223194] Call Trace: > [ 491.223198] __schedule+0x36b/0x950 > [ 491.223206] ? pick_next_task_fair+0xcf/0x3e0 > [ 491.223218] schedule+0x68/0xe0 > [ 491.223225] schedule_timeout+0x209/0x2a0 > [ 491.223236] wait_for_completion+0x8b/0xf0 > [ 491.223246] io_wq_manager+0xf1/0x1d0 > [ 491.223255] ? recalc_sigpending+0x1c/0x60 > [ 491.223265] ? io_wq_cpu_online+0x40/0x40 > [ 491.223272] ret_from_fork+0x22/0x30 > > When io-wq worker exits and sees IO_WQ_BIT_EXIT it tries not cancel all > left requests but to execute them, hence we may wait for the exiting > task for long until someone pushes it, e.g. with SIGKILL. Actively > cancel pending work items on io-wq destruction. > > note: io_run_cancel() moved up without any changes. Just to pull some of the discussion in here - I don't think this is a good idea as-is. At the very least, this should be gated on UNBOUND, and just waiting for bounded requests while canceling unbounded ones. -- Jens Axboe
