Dropping non supported kernels for kernel backports ?

Dropping non supported kernels for kernel backports ?

[Luis R. Rodriguez]

Today the backports project provides support to backport down to
2.6.24 for some subsystems. While this is good for users in practice
for development and maintenance this is quite a bit of overhead. Apart
from older kernels there are also gaps in between stable releases that
are not supported. For example 3.8 and 3.4 are supported but anything
in between is not (3.5, 3.6, 3.7), but we still do support them on the
backports project. At times this may mean a stable fix may get
propagated onto a the linux-3.4.y branch but obviously not the the
linux-3.5.y branch. If backporting expressing this becomes a bit
complex and we have dealt with it. In short, its a pain.

I'd like to see what folks thought if we went ahead and *only*
supported kernels listed on kernel.org as supported. This would help
with the Linux kernel maintainer effort by also persuading users to
upgrade to stable releases as well as educating around this.

If v3.10 backported releases are too soon to do this I propose we
seriously consider it for v3.11 releases. Any thoughts?

  Luis

Re: Dropping non supported kernels for kernel backports ?

[Johannes Berg]

On Tue, 2013-05-07 at 16:53 -0700, Luis R. Rodriguez wrote:
> Today the backports project provides support to backport down to
> 2.6.24 for some subsystems. While this is good for users in practice
> for development and maintenance this is quite a bit of overhead. Apart
> from older kernels there are also gaps in between stable releases that
> are not supported. For example 3.8 and 3.4 are supported but anything
> in between is not (3.5, 3.6, 3.7), but we still do support them on the
> backports project. At times this may mean a stable fix may get
> propagated onto a the linux-3.4.y branch but obviously not the the
> linux-3.5.y branch. If backporting expressing this becomes a bit
> complex and we have dealt with it. In short, its a pain.
> 
> I'd like to see what folks thought if we went ahead and *only*
> supported kernels listed on kernel.org as supported. This would help
> with the Linux kernel maintainer effort by also persuading users to
> upgrade to stable releases as well as educating around this.
> 
> If v3.10 backported releases are too soon to do this I propose we
> seriously consider it for v3.11 releases. Any thoughts?

I'm sure I'd still have to support other kernels random customers might
be on (customers, they don't always do the smart thing ;-) ). I could do
that myself of course, but then where would I stick the support patches?

Maybe we could do a compromise and drop support for no longer supported
kernels, but only a few years later? If we put the cutoff at 3 years now
we'd drop everything before 2.6.34, for example.

johannes

Re: Dropping non supported kernels for kernel backports ?

[Hauke Mehrtens]

On 05/08/2013 08:55 AM, Johannes Berg wrote:
> On Tue, 2013-05-07 at 16:53 -0700, Luis R. Rodriguez wrote:
>> Today the backports project provides support to backport down to
>> 2.6.24 for some subsystems. While this is good for users in practice
>> for development and maintenance this is quite a bit of overhead. Apart
>> from older kernels there are also gaps in between stable releases that
>> are not supported. For example 3.8 and 3.4 are supported but anything
>> in between is not (3.5, 3.6, 3.7), but we still do support them on the
>> backports project. At times this may mean a stable fix may get
>> propagated onto a the linux-3.4.y branch but obviously not the the
>> linux-3.5.y branch. If backporting expressing this becomes a bit
>> complex and we have dealt with it. In short, its a pain.
>>
>> I'd like to see what folks thought if we went ahead and *only*
>> supported kernels listed on kernel.org as supported. This would help
>> with the Linux kernel maintainer effort by also persuading users to
>> upgrade to stable releases as well as educating around this.
>>
>> If v3.10 backported releases are too soon to do this I propose we
>> seriously consider it for v3.11 releases. Any thoughts?
> 
> I'm sure I'd still have to support other kernels random customers might
> be on (customers, they don't always do the smart thing ;-) ). I could do
> that myself of course, but then where would I stick the support patches?
> 
> Maybe we could do a compromise and drop support for no longer supported
> kernels, but only a few years later? If we put the cutoff at 3 years now
> we'd drop everything before 2.6.34, for example.
> 
> johannes

I it is not often that something compat depends on gets backported into
some longterm kernel. The majority ~90% of backports added to compat are
not backported to any longterm kernel. If we want to support some kernel
version I do not think it is a hard task to support the versions in between.

Instead of supporting everything back to 2.6.34 I would like to got to
2.6.32 because this was used in Debian squeeze, RedHat 6 and some Ubuntu
long term version.

Dropping support for kernel versions not older than a year but not
supported any more is a bad idea, because the big distributions often
pick a non longterm kernel as their distribution kernel. Than we would
not even support the recent Ubuntu versions for a long time. Ubuntu
12.10 uses kernel 3.5 and Ubuntu 13.04 uses 3.8, both are no longterm
kernel versions.

Hauke