Re: Linux 2.6.17-rc2 - notifier chain problem?

[Chandra Seetharaman <sekharan@us.ibm.com>]

On Wed, 2006-04-26 at 11:49 -0400, Alan Stern wrote:
> On Mon, 24 Apr 2006, Andrew Morton wrote:
<snip>

> > I guess for now, bringing those things into .text and .data when there's
> > doubt is a reasonable thing to do.
> 
> It seems clear that this particular oops was caused by the xfs driver 
> trying to register a cpu_notifier at a time when that notifier chain was 
> expected to be completely idle.
> 
> Instead of moving all this code and data out of the init sections, 
> wouldn't it be better to fix the individual drivers (like xfs) so they 
> won't try to use inaccessible notifier chains?
> 
> For that matter, if lots of entries on the cpu_notifier chain are marked 
> with __cpuinit, then shouldn't the chain header itself plus 
> register_cpu_notifier and unregister_cpu_notifier be marked the same way?

Your suggestion is very valid, since the cpu_notifiers are called only
at init time, unless CONFIG_HOTPLUG_CPU is turned ON. Definitions of
__cpuinit and __cpuinitdata takes care of HOTPLUG config option.

XFS wants to register only for HOTPLUG_CPU case, and it do so by putting
the callback, register and unregister inside #ifdef HOTPLUG_CPU.

Note: I made the changes and tested, it works.

Andrew, Linus, Any comments ?

> Alan Stern
> 
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------