From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: Re: v3.7: Unloading ib_ipoib triggers circular locking dependency complaint Date: Wed, 13 Mar 2013 17:43:09 +0200 Message-ID: <51409E8D.7030304@mellanox.com> References: <50AF67C5.7090200@acm.org> <513F3455.3030309@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <513F3455.3030309-HInyCGIudOg@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche Cc: Roland Dreier , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 12/03/2013 15:57, Bart Van Assche wrote: > On 11/26/12 09:00, Or Gerlitz wrote: >> On Fri, Nov 23, 2012 at 2:10 PM, Bart Van Assche >> wrote: >>> Apparently unloading the ib_ipoib kernel module triggers a circular >>> locking >>> dependency complaint. Has anyone already been looking into this ? >> >> Yes, I see that this happens here e.g when doing hot-unplug to the >> underlying HW driver, seems related to the ipoib rtnl ops patches I >> pushed to 3.7 -- will look into this, thanks for bringing this up. >> Does anyone has an idea where the "s_active" lock is defined and what >> is its role? > > (replying to an e-mail from a few months ago) I still see this with > kernel 3.8.0. This warning probably means that sysfs_remove_dir() is > invoked with the rtnl lock held. If so I think that this can trigger a > deadlock during module removal. Yep, something goes wrong w.r.t to the interaction with sysfs and rtnl, at some point very similar lockdep traces were sent to netdev from other drivers and a generic solution was suggested, but I am not sure where this has landed, see http://marc.info/?l=linux-kernel&m=135293378513907&w=2 http://marc.info/?l=linux-netdev&m=135438302622434&w=2 Or. -- 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