From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: lockdep dump on devtree_lock (involving esdhc) Date: Wed, 12 Jun 2013 11:56:34 -0500 Message-ID: <1371056194.18413.34@snotra> References: <20130611233330.GA15342@home.buserror.net> <51B89723.7090808@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <51B89723.7090808@wwwdotorg.org> (from swarren@wwwdotorg.org on Wed Jun 12 10:43:31 2013) Content-Disposition: inline Sender: linux-mmc-owner@vger.kernel.org To: Stephen Warren Cc: devicetree-discuss@lists.ozlabs.org, Thomas Gleixner , Jerry Huang , linux-mmc@vger.kernel.org List-Id: devicetree@vger.kernel.org On 06/12/2013 10:43:31 AM, Stephen Warren wrote: > On 06/11/2013 05:33 PM, Scott Wood wrote: > > I get the following lockdump output on p2020rdb using > > v3.10-rc5-43-g34376a5. While it's not particularly polite for the > > esdhc driver to be calling OF functions while holding another lock > which > > can be acquired from interrupt context, why is devtree_lock usually > > acquired in an irqsafe manner but sometimes not? > > > > Both types of usage were added by the same commit: > > > > commit d6d3c4e656513dcea61ce900f0ecb9ca820ee7cd > > Author: Thomas Gleixner > > Date: Wed Feb 6 15:30:56 2013 -0500 > > > > OF: convert devtree lock from rw_lock to raw spinlock > > > > Stephen, you asked about this here: > > http://lkml.indiana.edu/hypermail/linux/kernel/1302.1/01383.html > > > > Did you ever get an answer? > > I believe that was fixed by c31a0c0 "of: fix recursive locking in > of_get_next_available_child()". That may have fixed the hang that prompted that thread, but it didn't answer the question you raised about mixing irqsafe and non-irqsafe devtree_lock uses. -Scott