Re: [PATCH] ioapic: fix potential resume deadlock
From: Suresh Siddha
Date: Mon May 16 2011 - 13:04:16 EST
On Mon, 2011-05-16 at 04:32 -0700, Ingo Molnar wrote:
> * Daniel J Blueman <daniel.blueman@xxxxxxxxx> wrote:
> > Hi Suresh,
> > On 14 May 2011 01:48, Suresh Siddha <suresh.b.siddha@xxxxxxxxx> 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@xxxxxxxxx>
> > >
> > > 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...
oops. I had a spurious initialization, from the earlier attempts to fix
this that was still left out.
> No. Has this been introduced by Suresh's patch?
Ofcourse yes ;(
Will fix this and split the patch into multiple steps.
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