Re: [PATCH 4.9 00/75] 4.9.74-stable review

[David Miller]

From: Neal Cardwell <ncardwell@xxxxxxxxxx>
Date: Tue, 2 Jan 2018 11:57:59 -0500

> On Mon, Jan 1, 2018 at 9:31 AM, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>> This is the start of the stable review cycle for the 4.9.74 release.
>> There are 75 patches in this series, all will be posted as a response
>> to this one.  If anyone has any issues with these being applied, please
>> let me know.
>>
>> Responses should be made by Wed Jan  3 14:00:03 UTC 2018.
>> Anything received after that time might be too late.
>>
>> The whole patch series can be found in one patch at:
>>         kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.74-rc1.gz
>> or in the git tree and branch at:
>>   git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
>> and the diffstat can be found below.
> 
> Hi Greg,
> 
> In looking at the 4.9 and 4.14 patches yesterday, I noticed there were
> two TCP BBR fixes that made it into 4.14 but not 4.9. Doing an
> inventory of the TCP BBR fixes, AFAICT we have:
> 
> c589e69b508d tcp_bbr: record "full bw reached" decision in new
> full_bw_reached bit
>  - in 4.9 and 4.14 (great)
> 
> 2f6c498e4f15 tcp_bbr: reset full pipe detection on loss recovery undo
>   - in 4.14 (but not 4.9)
> 
> 600647d467c6 tcp_bbr: reset long-term bandwidth sampling on loss recovery undo
>   - in 4.14 (but not 4.9)
> 
> Lacking the second and third patches in 4.9 will not cause any new
> problems, but it will miss out on some nice fixes. If it's possible to
> get  2f6c498e4f15 and 600647d467c6 either into 4.9.74 or 4.9.75, I
> would be very grateful.

These were not straight-forward to backport and I felt the risk outweighed
the gains.

If you want to do the backport yourself and you feel confident in it,
feel free.