On Fri, Dec 07, 2018 at 12:05:37PM -0800, Sagi Grimberg wrote: > > > Could you please take a look at this bug and code review? > > > > We are seeing more instances of this bug and found that reconnect_work > > could hang as well, as can be seen from below stacktrace. > > > > Workqueue: nvme-wq nvme_rdma_reconnect_ctrl_work [nvme_rdma] > > Call Trace: > > __schedule+0x2ab/0x880 > > schedule+0x36/0x80 > > schedule_timeout+0x161/0x300 > > ? __next_timer_interrupt+0xe0/0xe0 > > io_schedule_timeout+0x1e/0x50 > > wait_for_completion_io_timeout+0x130/0x1a0 > > ? wake_up_q+0x80/0x80 > > blk_execute_rq+0x6e/0xa0 > > __nvme_submit_sync_cmd+0x6e/0xe0 > > nvmf_connect_admin_queue+0x128/0x190 [nvme_fabrics] > > ? wait_for_completion_interruptible_timeout+0x157/0x1b0 > > nvme_rdma_start_queue+0x5e/0x90 [nvme_rdma] > > nvme_rdma_setup_ctrl+0x1b4/0x730 [nvme_rdma] > > nvme_rdma_reconnect_ctrl_work+0x27/0x70 [nvme_rdma] > > process_one_work+0x179/0x390 > > worker_thread+0x4f/0x3e0 > > kthread+0x105/0x140 > > ? max_active_store+0x80/0x80 > > ? kthread_bind+0x20/0x20 > > > > This bug is produced by setting MTU of RoCE interface to '568' for > > test while running I/O traffics. > > I think that with the latest changes from Keith we can no longer rely > on blk-mq to barrier racing completions. We will probably need > to barrier ourselves in nvme-rdma...
You really need to do that anyway. If you were relying on blk-mq to save you from double completions by ending a request in the nvme driver while the lower half can still complete the same one, the only thing preventing data corruption is the probability the request wasn't reallocated for a new command.
