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Date: Fri, 19 Jan 2018 08:50:18 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: David Rientjes <rientjes@google.com>
Cc: stable@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Christoph Hellwig <hch@lst.de>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [patch stable 4.9] scsi: sg: disable SET_FORCE_LOW_DMA
Message-ID: <20180119075018.GC25687@kroah.com>
References: <alpine.DEB.2.10.1801181341320.205153@chino.kir.corp.google.com>
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On Thu, Jan 18, 2018 at 01:42:17PM -0800, David Rientjes wrote:
> From: Hannes Reinecke <hare@suse.de>
> 
> commit 745dfa0d8ec26b24f3304459ff6e9eacc5c8351b upstream.
> 
> The ioctl SET_FORCE_LOW_DMA has never worked since the initial git
> check-in, and the respective setting is nowadays handled correctly. So
> disable it entirely.
> 
> [rientjes@google.com: the SG_SET_FORCE_LOW_DMA ioctl can race with
>  mmap(MAP_POPULATE) or a VM_LOCKED vma to cause a use-after-free which
>  can result in a GPF in practice.]

Thanks, I had already queued this up for 4.9, 4.4, and 3.18 last night,
sorry you were not cc:ed on that.

greg k-h