[Linux-kernel-mentees] Linux kernel checkpatch.pl mentorship

Dwaipayan Ray dwaipayanray1 at gmail.com
Sat Sep 12 09:09:06 UTC 2020

On Fri, Sep 11, 2020 at 12:59 PM Lukas Bulwahn <lukas.bulwahn at gmail.com>

> Dear Dwaipayan,
> The zeroth task is to learn suitable netiquette for the communication with
> the kernel community.
> First, please do not top-post.
>     A: Because we read from top to bottom, left to right.
>     Q: Why should I start my reply below the quoted text?
>     A: Because it messes up the order in which people normally read text.
>     Q: Why is top-posting such a bad thing?
>     A: The lost context.
>     Q: What makes top-posted replies harder to read than bottom-posted?
>     A: Yes.
>     Q: Should I trim down the quoted part of an email to which I'm
> replying?
> Second, please always CC: linux-kernel-mentees at lists.linuxfoundation.org.
> Third, set up your email client according to the kernel community rules.
> Then, the first task is to run checkpatch.pl on a few kernel patches and
> collect the results. When you have that, please share your script with
> me, e.g., in a github repository.
> Hints to the first task:
> Can you create a list of all non-merge commits that were added in the
> version v5.8 of the kernel, i.e., all non-merge commits that are in v5.8
> and not already in v5.7?
> Can you share the script/command you executed and the resulting list on
> github?
> Can you run your script on all commits of this list above and record
> all checkpatch.pl reports, and store them in your github repository?
> Can you suggest ideas how to aggregate the findings and create a
> statistics? For example: Which type of error is reported most?
> Can you implement that idea?
> I also suggest to have a look at the options ./scripts/checkpatch.pl
> --list-types and ./scripts/checkpatch.pl --show-types. The option
> --show-types changes the output of checkpatch.pl to list type
> identifiers,
> so it is easier to parse and aggregate the output.
> Please also share the script you create for that purpose on your
> github repository.
> The second task is to pick one warning that appears often and improve
> checkpatch.pl to handle that better and get it accepted by the kernel
> community.
> Hints to the second task follow when the first task is solved.
> If you fail on any of those tasks, you are out of the selection process.
> I could implement that with just a few lines of code changes, but please
> do not underestimate the learning curve here. I hope you are very fit in
> Perl, that is required for this project.
> Lukas

Hello Sir,
I have gone through the zeroth task and I am aware of the mailing rules
Also I have implemented the first task and I would like you to review it.

The task was to run checkpatch.pl on some commits and aggregate the

The first subtask was to collect the non merge commits between versions 5.7
and 5.8.
I aggregated the commit hashes and author names into a single file using
git's log
and pretty format directives.

The next subtask was to run checkpatch.pl on all the given commits.
I wrote a perl script to this effect which reads the commits stored in the
file and runs the checkpatch.pl script with the commit hash. Also I used
--show-types directives in this stage which allowed me easier collection of
warning and error identifiers.

The final subtask was to aggregate and parse the data. Looking at the
checkpatch's output
format, I determined it was enough to parse only the first two tokens from
each line.
I calculated three possibilities:  "WARNING:{warning_identifier}",
"Commit {commit_abbrev_hash}", and aggregated these values.

Finally I used them to find total commits read, total errors, total
and the most frequent warnings and errors from checkpatch's output.

I have uploaded the scripts and output files to

Hoping to get your review soon.

Thanking you,
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