From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
kernel-dev@igalia.com, kernel@gpiccoli.net, anton@enomsg.org,
ccross@android.com, tony.luck@intel.com
Subject: Re: [PATCH 2/8] pstore: Expose kmsg_bytes as a module parameter
Date: Wed, 12 Oct 2022 12:33:36 -0300 [thread overview]
Message-ID: <267ccf8f-1fea-7648-ec2b-e7f4ae822ae4@igalia.com> (raw)
In-Reply-To: <202210061628.76EAEB8@keescook>
On 06/10/2022 20:32, Kees Cook wrote:
> [...]
> Doing a mount will override the result, so I wonder if there should be
> two variables, etc... not a concern for the normal use case.
>
> Also, I've kind of wanted to get rid of a "default" for this and instead
> use a value based on the compression vs record sizes, etc. But I didn't
> explore it.
>
For some reason I forgot to respond that, sorry!
I didn't understand exactly how the mount would override things; I've
done some tests:
(1) booted with the new kmsg_bytes module parameter set to 64k, and it
was preserved across multiple mount/umount cycles.
(2) When I manually had "-o kmsg_bytes=16k" set during the mount
operation, it worked as expected, setting the thing to 16k (and
reflecting in the module parameter, as observed in /sys/modules).
Maybe I'm missing something?
Now, regarding the idea of setting that as a function of
compression/record_sizes, I feel it makes sense and could be worked,
like a heuristic right?
In the end, if you think properly, what is the purpose of kmsg_bytes?
Wouldn't make sense to just fill the record_size with the maximum amount
of data it can handle? Of course there is the partitioning thing, but in
the end kmsg_bytes seems a mechanism to _restrict_ the data collection,
so maybe the default would be a value that means "save whatever you can
handle" (maybe 0), and if the parameter/mount option is set, then pstore
would restrict the saved size.
Thoughts?
Thanks,
Guilherme
next prev parent reply other threads:[~2022-10-12 15:34 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-06 22:42 [PATCH 0/8] Some pstore improvements Guilherme G. Piccoli
2022-10-06 22:42 ` [PATCH 1/8] pstore: Improve error reporting in case of backend overlap Guilherme G. Piccoli
2022-10-06 23:27 ` Kees Cook
2022-10-06 23:35 ` Guilherme G. Piccoli
2022-10-06 22:42 ` [PATCH 2/8] pstore: Expose kmsg_bytes as a module parameter Guilherme G. Piccoli
2022-10-06 23:32 ` Kees Cook
2022-10-12 15:33 ` Guilherme G. Piccoli [this message]
2022-10-12 17:58 ` Kees Cook
2022-11-01 19:08 ` Guilherme G. Piccoli
2022-10-06 22:42 ` [PATCH 3/8] pstore: Inform unregistered backend names as well Guilherme G. Piccoli
2022-10-06 22:42 ` [PATCH 4/8] pstore: Alert on backend write error Guilherme G. Piccoli
2022-10-06 23:27 ` Kees Cook
2022-10-06 23:34 ` Guilherme G. Piccoli
2022-10-06 23:44 ` Kees Cook
2022-10-06 22:42 ` [PATCH 5/8] pstore: Fix long-term implicit conversions in the compression routines Guilherme G. Piccoli
2022-10-06 23:36 ` Kees Cook
2022-10-07 8:47 ` Ard Biesheuvel
2022-10-07 19:37 ` Kees Cook
2022-10-08 14:14 ` Guilherme G. Piccoli
2022-10-08 15:53 ` Ard Biesheuvel
2022-10-08 16:03 ` Guilherme G. Piccoli
2022-10-08 17:52 ` Ard Biesheuvel
2022-10-08 18:12 ` Guilherme G. Piccoli
2022-10-08 19:44 ` Kees Cook
2022-10-10 7:24 ` Ard Biesheuvel
2022-10-06 22:42 ` [PATCH 6/8] MAINTAINERS: Add a mailing-list for the pstore infrastructure Guilherme G. Piccoli
2022-10-06 23:22 ` Kees Cook
2022-10-06 23:29 ` Luck, Tony
2022-10-06 23:37 ` Kees Cook
2022-10-07 16:19 ` Luck, Tony
2022-10-07 16:21 ` Colin Cross
2022-10-07 16:32 ` Guilherme G. Piccoli
2022-10-07 19:25 ` Kees Cook
2022-10-06 22:42 ` [PATCH 7/8] efi: pstore: Follow convention for the efi-pstore backend name Guilherme G. Piccoli
2022-10-06 23:16 ` Kees Cook
2022-10-07 8:47 ` Ard Biesheuvel
2022-10-14 17:41 ` (subset) " Kees Cook
2022-10-06 22:42 ` [PATCH 8/8] efi: pstore: Add module parameter for setting the record size Guilherme G. Piccoli
2022-10-06 23:16 ` Kees Cook
2022-10-07 9:11 ` Ard Biesheuvel
2022-10-07 13:00 ` Guilherme G. Piccoli
2022-10-07 13:19 ` Ard Biesheuvel
2022-10-07 13:45 ` Guilherme G. Piccoli
2022-10-07 15:06 ` Ard Biesheuvel
2022-10-07 17:01 ` Guilherme G. Piccoli
2022-10-07 19:32 ` Kees Cook
2022-10-07 23:29 ` Guilherme G. Piccoli
2022-10-08 2:36 ` Kees Cook
2022-10-06 23:24 ` [PATCH 0/8] Some pstore improvements Kees Cook
2022-10-12 15:50 ` Guilherme G. Piccoli
2022-10-12 17:59 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=267ccf8f-1fea-7648-ec2b-e7f4ae822ae4@igalia.com \
--to=gpiccoli@igalia.com \
--cc=anton@enomsg.org \
--cc=ccross@android.com \
--cc=keescook@chromium.org \
--cc=kernel-dev@igalia.com \
--cc=kernel@gpiccoli.net \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tony.luck@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).