From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matt Fleming <matt@codeblueprint.co.uk>
Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() lockless
Date: Wed, 4 May 2016 14:36:56 +0100
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To: Borislav Petkov <bp@alien8.de>
Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Kweh Hock Leong <hock.leong.kweh@intel.com>, Bryan O'Donoghue <pure.logic@nexus-software.ie>, joeyli <jlee@suse.com>
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On Wed, 04 May, at 02:20:42PM, Borislav Petkov wrote:
> On Wed, May 04, 2016 at 12:46:05PM +0100, Matt Fleming wrote:
> > But emergency_restart() is called after bust_spinlocks(0) which can
> > reset oops_in_progress, so can't even use that to solve the panic
> > case.
> 
> Blergh.
> 
> So I guess you need an explicit call efi_stop_capsules() somewhere in
> the reboot path and be done with it. No reboot notifiers, no bla bla.
> Just one big hammer which STFU the EFI.

But you can't block in the reboot path and you can't guarantee you'll
interrupt an in-progress EFI capsule update call that started before
you entered the reboot path.