Re: How to verify linux-next

[Theodore Ts'o]

On Sat, Sep 30, 2017 at 09:28:09AM +0530, Pintu Kumar wrote:
> I need to submit a patch to mainline which should be verified against
> linux-next tree with latest API.

If you want to verify a patch that you intend to submit upstream, my
suggestion is to *not* use linux-next, but rather use the latest
tagged -rc from Linus's tree.  So for example, you might want to use
v4.14-rc2 as your base, and then apply your patch on top of v4.14-rc2.
And then test v4.14-rc2.  That way you don't need to worry about
debugging problems that might be caused by code in other people's
development trees.

If you know which subsystem tree your commit is going to be sent to,
you might use as your base the current development branch of that
subsystem tree.  But in general, it's fine to use something like
v4.14-rc2; if the subsystem maintainer you plan to be submitting your
patch has other preference, he or she will let you know, or take care
of rebasing your patch onto his subsystme tree.

> My patch is related to some test utility based on client/server model.
> So, I need 2 terminal, one for server and one for client.

That implies you're running the commands to run the test by hand.  In
the ideal world, tests should be automated, even those that are using
client/server so that tests can be run unattended, over and over
again.

For example, here's an example of test involving a client and a server
in xfstests:

https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/generic/131

See?  No terminal required, and certainly not two terminals!

Remember, it's important not just to run one test, because the risk is
that fixing one bug might cause a test regression somewhere else.  So
when I "validate" a kernel, I'm running thousands of tests, just to
test the ext4 file system.  For each bug that we fix, we try to add a
new automated test, so we can be sure that some future change doesn't
cause a bug to reappear.  And if you're running hundreds or thousands
of tests, you certainly aren't going to be wanting to manually set up
each test by using putty to login to the VM using ssh!

> 1) How to resolve linux-next build error with ubuntu virtual box 5.1.28

Virtual box is not relevant.  What is relevant is the kernel config
file you are using, and what compiler version / distro are you using
to build the kernel.  And as I said, you're better off using something
like v4.14-rc2 instead of linux-next.

					- Ted