On 10/14/19 12:38 PM, Knut Omang wrote:
On Mon, 2019-10-14 at 10:42 +0000, Luis Chamberlain wrote:
On Fri, Sep 13, 2019 at 02:02:47PM -0700, Brendan Higgins wrote:
Hey Knut and Shuah,
Following up on our offline discussion on Wednesday night:
We decided that it would make sense for Knut to try to implement Hybrid
Testing (testing that crosses the kernel userspace boundary) that he
introduced here[1] on top of the existing KUnit infrastructure.
We discussed several possible things in the kernel that Knut could test
with the new Hybrid Testing feature as an initial example. Those were
(in reverse order of expected difficulty):
1. RDS (Reliable Datagram Sockets) - We decided that, although this was
one of the more complicated subsystems to work with, it was probably
the best candidate for Knut to start with because it was in desperate
need of better testing, much of the testing would require crossing
the kernel userspace boundary to be effective, and Knut has access to
RDS (since he works at Oracle).
Any update on if you are able to explore this work.
2. KMOD - Probably much simpler than RDS, and the maintainer, Luis
Chamberlain (CC'ed) would like to see better testing here, but
probably still not as good as RDS because it is in less dire need of
testing, collaboration on this would be more difficult, and Luis is
currently on an extended vacation. Luis and I had already been
discussing testing KMOD here[2].
I'm back!
I'm also happy and thrilled to help review the infrastructure in great
detail given I have lofty future objectives with testing in the kernel.
Also, kmod is a bit more complex to test, if Knut wants a simpler *easy*
target I think test_sysctl.c would be a good target. I think the goal
there would be to add probes for a few of the sysctl callers, and then
test them through userspace somehow, for instance?
That sounds like a good case for the hybrid tests.
The challenge in a kunit setting would be that it relies on a significant part of KTF
to work as we have used it so far:
- module support - Alan has been working on this
I see the patches. Thanks for working on this.
- netlink approach from KTF (to allow user space execution of kernel
part of test, and gathering reporting in one place)
- probe infrastructure
The complexities with testing kmod is the threading aspect. So that is
more of a challenge for a test infrastructure as a whole. However kmod
also already has a pretty sound kthread solution which could be used
as basis for any sound kernel multithread test solution.
Curious, what was decided with the regards to the generic netlink approach?
Can this work be be done without netlink approach? At least some of it.
I would like to see some patches and would like to get a better feel
for the dependency on generic netlink.
I think in some way functionality similar to the netlink support is needed
for the features in KTF that we discussed, so I get it is a "yes" to add
support for it?
See above.
thanks,
-- Shuah
