Re: [PATCH v5 1/3] Provide in-kernel headers to make extending kernel easier

From: Karim Yaghmour
Date: Mon Apr 08 2019 - 16:52:24 EST

Hi Olof,

On 4/8/19 12:29 PM, Olof Johansson wrote:
Sorry to be late at the party with this kind of feedback, but I find
the whole ".tar.gz in procfs" to be an awkward solution, especially if
there's expected to be userspace tooling that depends on this

Wouldn't it be more convenient to provide it in a standardized format
such that you won't have to take an additional step, and always have
it in a known location?

Something like:

- Pseudo-filesystem, that can just be mounted under
/sys/kernel/headers or something (similar to debugfs or
- Exporting something like a squashfs image instead, allowing
loopback mounting of it (or by providing a pseudo-/dev entry for it),
again allowing direct export of the contents and avoiding the
extracted directory from being out of sync with currently running

Having to copy and extract the tarball is the most awkward step, IMHO.
I also find the waste of kernel memory for it to be an issue, but
given that it can be built as a module I guess that's the obvious
solution for those who care about memory consumption.

One of the things I pointed out earlier in the thread is that /proc/config.gz has already set a precedent as to the interface for this sort of artifact. It's a plain compressed file and it's directly accessible from toplevel /proc. From a consistency perspective there's an idiomatic angle to some sort of "/proc/kheaders.gz".

In some offline discussions I was also told that squashfs (I'm no expert of it) required special user-space tools and had some security issues.


Karim Yaghmour
CEO - Opersys inc. /