linux-kernel - Re: [PATCH] ioapic: fix potential resume deadlock

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Date:	Sat, 14 May 2011 22:39:01 +0800
From:	Daniel J Blueman <daniel.blueman@...il.com>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, H Peter Anvin <hpa@...or.com>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ioapic: fix potential resume deadlock

Hi Suresh,

On 14 May 2011 01:48, Suresh Siddha <suresh.b.siddha@...el.com> wrote:
> On Wed, 2011-05-11 at 09:15 -0700, Daniel J Blueman wrote:
>> Superb, this works, tested against 2.6.39-rc7 and addresses the "BUG:
>> sleeping function called from invalid context at mm/slub.c:824"
>> warning I was previously seeing. It would be good to get this fix into
>> 2.6.39-final if possible.
>>
>> Tested-by: Daniel J Blueman <daniel.blueman@...il.com>
>
> Thanks Daniel for testing my quick patch. I have appended the complete
> patch which cleans up this code.
>
> Ingo, This patch is relatively big (mostly removes the duplicate code
> and changes the location where we allocate ioapic_saved_data, so that
> this can be shared between interrupt-remapping and io-apic
> suspend/resume flows). May be this can go into 2.6.40-rc1 and probably
> go to 2.6.39-stable?
>
> Or we can take the Daniel's GFP_ATOMIC patch for 2.6.39 and push this
> patch for 2.6.40-rc1. I am ok either way.
[]

Testing this, all looks well in that the patch resolves the
potentially sleeping allocation, however I do see (on boot) this
suspicious message (though suspend and resume does work):

IOAPIC 0: suspend/resume impossible!

I guess it's not expected...
-- 
Daniel J Blueman
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