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From: David Miller <davem@davemloft.net>
To: srn@prgmr.com
Cc: tariqt@mellanox.com, yishaih@mellanox.com, netdev@vger.kernel.org
Subject: Re: [PATCH v2] net/mlx4_en: fix potential use-after-free with dma_unmap_page
Date: Fri, 27 Apr 2018 19:48:59 -0400 (EDT)	[thread overview]
Message-ID: <20180427.194859.554972405986118921.davem@davemloft.net> (raw)
In-Reply-To: <1524715234-20002-1-git-send-email-srn@prgmr.com>

From: Sarah Newman <srn@prgmr.com>
Date: Wed, 25 Apr 2018 21:00:34 -0700

> When swiotlb is in use, calling dma_unmap_page means that
> the original page mapped with dma_map_page must still be valid
> as swiotlb will copy data from its internal cache back to the
> originally requested DMA location. When GRO is enabled,
> all references to the original frag may be put before
> mlx4_en_free_frag is called, meaning the page has been freed
> before the call to dma_unmap_page in mlx4_en_free_frag.
> 
> To fix, unmap the page as soon as possible.
> 
> This can be trivially detected by doing the following:
> 
> Compile the kernel with DEBUG_PAGEALLOC
> Run the kernel as a Xen Dom0
> Leave GRO enabled on the interface
> Run a 10 second or more test with iperf over the interface.
> 
> Signed-off-by: Sarah Newman <srn@prgmr.com>

Tariq, I assume I will get this from you in the next set of
changes you submit to me.

Thanks.

  reply	other threads:[~2018-04-27 23:49 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-05  4:20 [PATCH] net/mlx4_en: fix potential use-after-free with dma_unmap_page Sarah Newman
2018-03-05 10:09 ` Tariq Toukan
2018-03-05 21:10   ` Sarah Newman
2018-03-06 16:13     ` Tariq Toukan
2018-03-06 20:16       ` Sarah Newman
2018-03-11 15:15         ` Tariq Toukan
2018-04-26  4:00           ` [PATCH v2] " Sarah Newman
2018-04-27 23:48             ` David Miller [this message]
2018-05-02 13:50               ` Tariq Toukan
2018-05-02 14:26                 ` David Miller
2018-05-31  1:04                   ` [PATCH v3] " Sarah Newman
2018-05-31  5:36                     ` Greg KH
2018-05-31 17:15                       ` Sarah Newman
2018-06-02 13:33                         ` Greg KH

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