From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Steve Wise" Subject: RE: device removal hangs where there are open uverbs refs Date: Mon, 24 Mar 2014 09:25:08 -0500 Message-ID: <001401cf476c$db7e95e0$927bc1a0$@opengridcomputing.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-us Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: 'Or Gerlitz' , 'Roland Dreier' Cc: 'Bart Van Assche' , 'linux-rdma' List-Id: linux-rdma@vger.kernel.org > -----Original Message----- > From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On > Behalf Of Or Gerlitz > Sent: Monday, March 24, 2014 2:16 AM > To: Roland Dreier > Cc: Bart Van Assche; linux-rdma > Subject: device removal hangs where there are open uverbs refs > > Hi Roland, > > >From time to time I get a customer case which goes through something > like the below trace which steps on a design limitation of the > upstream IB stack -- namely, if you have a process with open uverbs > reference -- device removal flow hangs and this would happen with any > device/driver, nothing specific to mlx4. So... I think it's about time > to address it. > > Can't we just foricibly close their uverbs file descriptor from within > the kernel and drop the ref? > Here is a previous thread discussing the issue in 2010: http://marc.info/?l=linux-rdma&m=126961887406371&w=3 > Or. > > INFO: task mlx4:2003 blocked for more than 120 seconds. > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > Call Trace: > [] schedule_timeout+0x215/0x2e0 > [] wait_for_common+0x123/0x180 > [] wait_for_completion+0x1d/0x20 > [] ib_uverbs_remove_one+0x73/0xa0 [ib_uverbs] > [] ib_unregister_device+0x4f/0x100 [ib_core] > [] mlx4_ib_remove+0x26/0x110 [mlx4_ib] > [] mlx4_remove_device+0x71/0x90 [mlx4_core] > [] mlx4_unregister_device+0x43/0x90 [mlx4_core] > [] mlx4_change_port_types+0x68/0x120 [mlx4_core] > [] mlx4_sense_port+0x9b/0xd0 [mlx4_core] > [] worker_thread+0x170/0x2a0 > [] kthread+0x96/0xa0 > [] child_rip+0xa/0x20 > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html