Re: CONFIG_UEVENT_HELPER default

[Andy Lutomirski <luto@amacapital.net>]

On 06/24/2014 11:33 AM, Greg KH wrote:
> On Tue, Jun 24, 2014 at 11:30:05AM -0700, Michael Marineau wrote:
>> On Jun 24, 2014 11:23 AM, "Alan Stern" <stern@rowland.harvard.edu> wrote:
>>>
>>> Michael and Greg:
>>>
>>> The help text for CONFIG_UEVENT_HELPER says (among other things):
>>>
>>>           This should not be used today, because usual systems create
>>>           many events at bootup or device discovery in a very short time
>>>           frame.
>>>
>>> If it shouldn't be used, why does it default to 'y'?
>>>
>>> Alan Stern
>>>
>>
>> To introduce the option but not change the default behavior. (yet?) I don't
>> really have an opinion one way or the other, I just defaulted to being
>> conservative.
> 
> Yes, being conservative is good as turning this off with older systems
> (like the pathological Fedora 3 system that some kernel developers still
> use for testing), would result in a non-booting box.  So if you know
> that your system is "new enough", it's safe to turn off, but if you have
> a doubt, leave it on to be safe.

As far as I know, there's no real requirement that a defconfig kernel be
able to boot old userspace.  We want an oldconfig kernel to be able to
boot old userspace, but changing the default won't affect that.

For example, a defconfig kernel won't boot opensuse 9.

--Andy