Re: [PATCH] net/mlx4_en: fix potential use-after-free with dma_unmap_page

On 06/03/2018 10:16 PM, Sarah Newman wrote:

On 03/06/2018 08:13 AM, Tariq Toukan wrote:

quoted

I have a general question about the process.
I don't totally get what branch this patch is targeted to.
It touches critical areas in datapath and should go through regression tests before it is accepted to any branch.

This one is against 4.9 -
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/?h=linux-4.9.y

I assume you'd be interested in applying a fix to all currently maintained stable branches between 3.6 to 4.11, per
https://www.kernel.org/category/releases.html .

Yes.

I know of at least one other person whose workaround has been to disable GRO, but I don't understand the networking code well enough to guarantee that
disabling GRO means the problem will never occur under all possible error conditions. If it's guaranteed that disabling GRO will definitely mitigate
the bug, probably it's better to stop supporting GRO for these versions of the driver instead of trying to implement some other fix.

I don't think we have a guarantee, it just happens to work.
Also, disabling GRO will cause dramatic performance degradation.
We should fix this, not WA.

--Sarah