[PATCH 1/1] rcu: select IRQ_WORK from TREE_PREEMPT_RCU

[PATCH 1/1] rcu: select IRQ_WORK from TREE_PREEMPT_RCU

[James Hogan]

TREE_RCU and TREE_PREEMPT_RCU both cause kernel/rcutree.c to be built,
but only TREE_RCU selects IRQ_WORK, which can result in an undefined
reference to irq_work_queue for some (random) configs:

kernel/built-in.o In function `rcu_start_gp_advanced':
kernel/rcutree.c:1564: undefined reference to `irq_work_queue'

Select IRQ_WORK from TREE_PREEMPT_RCU too to fix this.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
---
 init/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/init/Kconfig b/init/Kconfig
index 247084b..c08a549 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -470,6 +470,7 @@ config TREE_RCU
 config TREE_PREEMPT_RCU
 	bool "Preemptible tree-based hierarchical RCU"
 	depends on PREEMPT
+	select IRQ_WORK
 	help
 	  This option selects the RCU implementation that is
 	  designed for very large SMP systems with hundreds or
-- 
1.8.1.2

Re: [PATCH 1/1] rcu: select IRQ_WORK from TREE_PREEMPT_RCU

[Paul E. McKenney]

On Thu, Jul 25, 2013 at 03:34:25PM +0100, James Hogan wrote:
> TREE_RCU and TREE_PREEMPT_RCU both cause kernel/rcutree.c to be built,
> but only TREE_RCU selects IRQ_WORK, which can result in an undefined
> reference to irq_work_queue for some (random) configs:
> 
> kernel/built-in.o In function `rcu_start_gp_advanced':
> kernel/rcutree.c:1564: undefined reference to `irq_work_queue'
> 
> Select IRQ_WORK from TREE_PREEMPT_RCU too to fix this.

Queued for 3.12, good catch, James!

							Thanx, Paul

> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: Dipankar Sarma <dipankar@in.ibm.com>
> ---
>  init/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index 247084b..c08a549 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -470,6 +470,7 @@ config TREE_RCU
>  config TREE_PREEMPT_RCU
>  	bool "Preemptible tree-based hierarchical RCU"
>  	depends on PREEMPT
> +	select IRQ_WORK
>  	help
>  	  This option selects the RCU implementation that is
>  	  designed for very large SMP systems with hundreds or
> -- 
> 1.8.1.2
> 
> 
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