linux-kernel - Re: [PATCH] iommu/core: fix bus notifier breakage

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Date:	Thu, 25 Sep 2014 16:47:54 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Mark Salter <msalter@...hat.com>
Cc:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Subject: Re: [PATCH] iommu/core: fix bus notifier breakage

On Sun, Sep 21, 2014 at 01:58:24PM -0400, Mark Salter wrote:
> iommu_bus_init() registers a bus notifier on the given bus by using
> a statically defined notifier block:
> 
>   static struct notifier_block iommu_bus_nb = {
>           .notifier_call = iommu_bus_notifier,
>   };
> 
> This same notifier block is used for all busses. This causes a
> problem for notifiers registered after iommu has registered this
> callback on multiple busses. The problem is that a subsequent
> notifier being registered on a bus which has this iommu notifier
> will also get linked in to the notifier list of all other busses
> which have this iommu notifier.
> 
> This patch fixes this by allocating the notifier_block at runtime.
> Some error checking is also added to catch any allocation failure
> or notifier registration error.
> 
> Signed-off-by: Mark Salter <msalter@...hat.com>
> ---
>  drivers/iommu/iommu.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)

Makes sense, applied. Where have you hit this condition where IOMMUs for
different buses are registered?


	Joerg

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