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Date: Fri, 08 May 2009 08:49:54 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ingo Molnar <mingo@elte.hu>, the arch/x86 maintainers <x86@kernel.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Xen-devel <xen-devel@lists.xensource.com>,
       Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Subject: Re: [PATCH 6/8] x86: use flush_tlb_others to implement	flush_tlb_all
References: <1241727902-3176-1-git-send-email-jeremy@goop.org>	 <1241727902-3176-7-git-send-email-jeremy@goop.org> <1241796269.15972.41.camel@zakaz.uk.xensource.com>
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Ian Campbell wrote:
> On Thu, 2009-05-07 at 13:25 -0700, Jeremy Fitzhardinge wrote:
>   
>> From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
>>
>> Use the flush_tlb_others() call to implement flush_tlb_all().
>>     
>
> This causes:
>         BUG: spinlock bad magic on CPU#0, swapper/0
>          lock: c05b7588, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
>         Pid: 0, comm: swapper Not tainted 2.6.30-rc3-x86_32p-xen0-tip-01797-g3db7847 #1054
>         Call Trace:
>          [<c023e656>] spin_bug+0x96/0xf0
>          [<c023e90f>] _raw_spin_lock+0x6f/0x150
>   

Ah, right.  I had another change (somewhere around here) to explicitly 
initialize the tlb flush code from the normal early init code, rather 
than make it implicit via initcall.  Otherwise we have an unknown point 
at which we're allowed to start using global flushes, which is a bit flakey.

    J