Re: [PATCH] fixes for rcu_offline_cpu, rcu_move_batch (2.6.8-rc2)

[Andrew Morton <akpm@osdl.org>]

Nathan Lynch <nathanl@austin.ibm.com> wrote:
>
> Hi,
> 
> rcu_offline_cpu and rcu_move_batch have been broken since the
> list_head's in struct rcu_head and struct rcu_data were replaced with
> singly-linked lists:
> 
>   CC      kernel/rcupdate.o
> kernel/rcupdate.c: In function `rcu_move_batch':
> kernel/rcupdate.c:222: warning: passing arg 2 of `list_add_tail' from
> incompatible pointer type
> kernel/rcupdate.c: In function `rcu_offline_cpu':
> kernel/rcupdate.c:239: warning: passing arg 1 of `rcu_move_batch' from
> incompatible pointer type
> kernel/rcupdate.c:240: warning: passing arg 1 of `rcu_move_batch' from
> incompatible pointer type
> kernel/rcupdate.c:236: warning: label `unlock' defined but not used

oop.  We really should find some way to get more people to enable CPU
hotplug.  We have a coverage problem.

> Kernel crashes when you try to offline a cpu, not surprisingly.
> 
> It also looks like rcu_move_batch isn't preempt-safe so I touched that
> up, and got rid of an unused label in rcu_offline_cpu.
> 
> This fixes the crash for me; does it look ok?
> 

Looks good to me, thanks.