Date: Wed, 25 May 2005 20:48:28 -0700
From: Andrew Morton <akpm@osdl.org>
To: Shaohua Li <shaohua.li@intel.com>
Cc: pavel@ucw.cz, linux-kernel@vger.kernel.org,
       David Mosberger <davidm@napali.hpl.hp.com>
Subject: Re: Hotplug CPU printk issue
Message-Id: <20050525204828.70acc1b5.akpm@osdl.org>
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	<1117076334.4086.11.camel@linux-hp.sh.intel.com>
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Shaohua Li <shaohua.li@intel.com> wrote:
>
>  > --- a/kernel/printk.c   2005-04-12 10:12:19.000000000 +0800 
>  > +++ b/kernel/printk.c   2005-04-13 17:22:40.912897328 +0800 
>  > @@ -624,8 +624,7 @@ asmlinkage int vprintk(const char *fmt,  
>  >                         log_level_unknown = 1; 
>  >         } 
>  >   
>  > -       if (!cpu_online(smp_processor_id()) && 
>  > -           system_state != SYSTEM_RUNNING) { 
>  > +       if (!cpu_online(smp_processor_id())) { 
>  >                 /* 
>  >                  * Some console drivers may assume that per-cpu resources have 
>  >                  * been allocated.  So don't allow them to be called by this
>  Andrew,
>  Could above patch be put into mm tree?

Well not in that form.  I'd appreciate being sent patches which are
applyable rather than mangled messes, please.

> It fixes the oops of CPU hotplug
>  with radeon fb enabled.
>  The reason is the per-cpu data (radeon fb calls kmalloc) isn't
>  initialized when CPU hotplug is processing. system_state is
>  SYSTEM_RUNNING for cpu hotplug.

That system_state test was explicitly added by davidm a year ago:

"- Allow printk on down cpus once system is running."

Please confirm that we in fact do not want to allow downed CPUs to
print things, then send a patch.
-
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