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Date: Thu, 5 Jan 2017 10:57:06 +0100
From: Christoph Hellwig <hch@lst.de>
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Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
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Subject: Re: [PATCH] virtio_blk: avoid DMA to stack for the sense buffer
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On Wed, Jan 04, 2017 at 04:47:03PM +0100, 王金浦 wrote:
> This sounds scary.
> Could you share how to reproduce it, this should go into stable if
> it's the case.

Step 1: Build your kernel with CONFIG_VMAP_STACK=y
Step 2: issue a SG_IO ioctl, e.g. sg_inq /dev/vda