rcu self-detected stall messages on OMAP3, 4 boards
From: paul@pwsan.com (Paul Walmsley)
Date: 2012-09-21 18:09:02
Also in:
linux-omap, lkml
cc Frederic Weisbecker - context is here: http://marc.info/?l=linux-kernel&m=134749030206016&w=2 On Thu, 20 Sep 2012, Paul E. McKenney wrote:
Fair point. I am wondering whether there is some path into the idle loop that somehow avoids telling RCU that the CPU has in face entered idle. There needs to be an rcu_idle_enter() call on the way to idle, otherwise RCU CPU stall warnings are expected behavior.
As far as I know, our only idle entry point is in
arch/arm/common/process.c:cpu_idle().
Looking at the x86 idle entry, they call rcu_idle_{enter,exit}() inside
{stop,start}_critical_timings(). Making that change here didn't help.
Also tried commenting out the code from the stop_critical_timings() call
to the WARN_ON(irqs_disabled()), and adding a local_irq_enable(). That
also didn't help, which suggests that the problem is not caused by the
OMAP-specific PM idle code.
- Paul