Re: suspicious RCU usage warnings in 3.3.0

[David Miller]

From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Date: Wed, 11 Apr 2012 17:45:07 -0700

> On Wed, Apr 11, 2012 at 08:18:54PM -0400, David Miller wrote:
>> From: Stephen Hemminger <shemminger@xxxxxxxxxx>
>> Date: Wed, 11 Apr 2012 17:10:04 -0700
>> 
>> > On Wed, 11 Apr 2012 16:08:37 -0700
>> > "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
>> > 
>> >> Hmmm...  What CPU family is this running on?  From the look of the
>> >> stack, it is sneaking out of idle into softirq without telling RCU.
>> >> This would cause RCU to complain bitterly about being invoked from
>> >> the idle loop -- and RCU ignores CPUs in the idle loop.
>> >> 
>> >> 							Thanx, Paul
>> > 
>> > Sun4... Ping David.
>> 
>> So is there anything specific I need to do in the sparc64
>> idle loop?
> 
> Hmmm...  I must confess that I don't immediately see how control
> is passing from cpu_idle() in arch/sparc/kernel/process_64.c to
> __handle_softirq().
> 
> But it looks like a simple function call in the call trace:

It's coming from the trap return code path at the end of hardware
interrupt processing, on the IRQ stack.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/