Messages in this thread | | | Date | Wed, 22 Aug 2012 09:03:32 +0800 | From | Fengguang Wu <> | Subject | Re: lockdep warning on rt_mutex_lock() |
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On Tue, Aug 21, 2012 at 12:21:49PM -0700, Paul E. McKenney wrote: > On Sat, Aug 18, 2012 at 12:59:08PM +0800, Fengguang Wu wrote: > > On Fri, Aug 17, 2012 at 07:44:37AM -0700, Paul E. McKenney wrote: > > > On Fri, Aug 17, 2012 at 10:02:40PM +0800, Fengguang Wu wrote: > > > > On Fri, Aug 17, 2012 at 06:43:28AM -0700, Paul E. McKenney wrote: > > > > > On Fri, Aug 17, 2012 at 06:06:35PM +0800, Fengguang Wu wrote: > > > > > > Greetings, > > > > > > > > > > > > FYI, a lockdep warning: > > > > > > > > > > Certainly looks problematic! > > > > > > > > > > Any hint as to what version of the kernel produced this splat? > > > > > (Yes, lazy of me to ask, I know, but I am not seeing it in my testing.) > > > > > > > > It happens on both 3.5.0 and 3.6-rc1. Will bisect (try older kernels) help? > > > > Bisect is handy for me :) > > > > > > Bisection would be very welcome!!! ;-) > > > > The bisect result is... > > Hmmm... This patch is a bit of a blast from the past. > > > commit 9e571a82f0cb205a65a0ea41657f19f22b7fabb8 > > Author: Paul E. McKenney <paul.mckenney@linaro.org> > > Date: Thu Sep 30 21:26:52 2010 -0700 > > > > rcu: add tracing for TINY_RCU and TINY_PREEMPT_RCU > > > > Add tracing for the tiny RCU implementations, including statistics on > > boosting in the case of TINY_PREEMPT_RCU and RCU_BOOST. > > > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > So the lockdep complaint indicates that lockdep and the actual hardware > had different opinions about whether or not interrupts were enabled. > One way that can happen is through use of raw_local_irq_save(). And this > commit did add a raw_local_irq_save(). > > So maybe converting to local_irq_save() will make things work better. > > Fengguang, could you please try out the following patch?
It reliably fixed the warnings. Thank you very much!
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
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