Kernel releases

[John Johansen]

On 07/30/2015 11:49 AM, Christopher.Carlson at zodiacaerospace.com wrote:
> Thank you for your reply, Paul.
> 
> BTW, I'm running 14.04.2 LTS.x86_64.
> 
> I also don't always restart, but I presume the only reason we got a kernel update is because of a bug or security, which encourages me to restart.  It nags at me (not the system, but my concern that there's a problem lurking).
> 
> My whining is brought on by my strong dislike of Microsoft, and I get irritated that I have to reboot my Windows 7 machine every week.  To think that Ubuntu is following in their footsteps concerns me.
> 
> Yes, I could scan the release notes to see if I really need this update, and thanks for the link.  I've only got 57 of them on my system. Ugh.  I have to clean up my /boot directory every couple of months or so to keep it reasonable.
> 
Yes there have been a lot of updates lately due to several kernel vulnerabilities that have been discovered.

The kernel has a regular update Cadence of every 3 weeks in which Ubuntu pulls in regular fixes from upstream stable releases. This will mostly contain bug fixes but there are usually a few security fixes as well. These kernels under go QA testing and are available in the proposed pocket for broader testing if someone is interested. The bug fixes are varied and maybe for bugs reported in launchpad but are often just upstream stable bug fixes that have been discovered and fixed as part of on going kernel development. Often the fixes are in drivers for specific hardware and you will never experience the issue if you're machine doesn't have that hardware. If a security fix can wait for the regular kernel update cadence it is usually a lower priority bug like a local denial of service issue. The important thing to remember about these kernels is that if you are not experiencing issues you generally don't need to install them, or can install them and just not reboot.

In addition to the regular kernel update Cadence there are "emergency" kernels that fix higher priority kernel issues as they come up. Ubuntu has no control over when these bugs are discovered or disclosed, so the only thing it can do is publish a patched kernel when an issue arises. Whether an individual will need to update for these emergency kernels depends on how they are using their machine. A single user system may not need to update for a local privilege escalation, where a vps hosting provider should. What Ubuntu doesn't do is batch important security fixes into a "patch Tuesday" type of update to reduce the number of updates.