reload kernel without reboot?

Lowell Gilbert freebsd-questions-local at
Mon Jun 15 13:50:55 UTC 2015

Jason Unovitch <jason.unovitch at> writes:

> On Jun 14, 2015 12:30 PM, "Polytropon" <freebsd at> wrote:
>> On Sun, 14 Jun 2015 13:24:59 +0430, takCoder wrote:
>> > my question is: Is there a way to reload freebsd kernel in which i don't
>> > need to restart to apply the changes?
>> Probably not, because the kernel is the first thing the
>> OS boot mechanism will load, and this is required at the
>> earliest stage of OS booting for the kernel to work as
>> intended. What you would need is to change the kernel
>> binary content (after source change and compile run)
>> both on disk and in memory, with all its location references
>> and dependency resolutions so the result parts will work
>> consistently again. I'd say that's a very hard task, nearly
>> impossible.
>> However, if you are able to move the things you want to
>> "dynamically load and unload" into kernel modules - there
>> might be a solution for you. Kernel modules can be dealt
>> with easily using kldload and kldunload. However, the
>> kernel itself cannot be unloaded and reloaded with those
>> tools.
> That is worth a read. I'm sure if it were easy it would have been
> implemented by now.

A standard kernel comes with many hundreds of kernel modules. We don't
know what you're working on specifically, but the building and loading
and unloading of modules is not tricky.

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