From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: ** X-Spam-Status: No, score=2.5 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54A45C433DB for ; Tue, 23 Mar 2021 15:12:14 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B48FB619B9 for ; Tue, 23 Mar 2021 15:12:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B48FB619B9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.94) (envelope-from ) id 1lOihP-0004Lf-IN; Tue, 23 Mar 2021 11:12:03 -0400 Received: from mail-vs1-xe2c.google.com ([2607:f8b0:4864:20::e2c]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1lOihN-0004LS-Sk for kernelnewbies@kernelnewbies.org; Tue, 23 Mar 2021 11:12:01 -0400 Received: by mail-vs1-xe2c.google.com with SMTP id e5so9569958vse.4 for ; Tue, 23 Mar 2021 08:12:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=Pcf4XwYrAJyfIwKPjVYYwwsYKiqjachK3mSYdzv/sMw=; b=qnzBCNRtpFPbL2K1Gg7w9XnbRC2QNFgU53kwVJtZT5NhB3keBhSlhc1GGNZXiLxcVb d0K86S3gnnbz52JzH0yMgw+tHYaLVn4amc09DlsGNQHQ1i6Uy+Ohaez2vrJWdU5+odeG BFGtVoJkIFBcPU2OfdjM0xzZs9ixLyofr+EmVLSs/t/fxRf+fk5wEjoXSGSOZ2SUKmhw sCxw79mGq5g4bxNw4yhYmddk/xXP55uneD89HuyCeyfRpZCC97DJQyHSpijH7DoXUEvP kl/Y5n4KWcSsTHStt+TgZJyN0bCbx1mNeZeSZuBkyJAejtm1K5+gyNEQpDjO7EQpxlPO af9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=Pcf4XwYrAJyfIwKPjVYYwwsYKiqjachK3mSYdzv/sMw=; b=mY+k4MP+gAQywK8pQUQl5YDT+s5XFYyUEOrO5Wehy/Px9Sn5ikE7g5GuMdZtVAY8n/ V1gdIWgwsVROZruI3v8aouYkl8K712vs6MIKbzXnXN6cPJYPeQX3lCoM7xdwikGEPcqD yKdyHPbD3aVGwiwr1DWtPknPXEm34T3d5582vi6kLkfwl/d7yRWUR+tIhij3FQD/JrA6 1zio6TWJErG8T2AINtkoyhOHLNcJ3vBrtW3syxvyk8wtsMyD8f6oxz2oMtN9iCvII31A Ho+ygGsN0RvjYlcDnooGJv5xZAu5OyAIIbwm8njXyrVp4F1YOmKl3gB6D5yTyYjNCW4M TaJQ== X-Gm-Message-State: AOAM531gOfB8ewXBLRWnAMKjjLJiiO2z9qv4K2xMKNGbkq9nxjlAtnYw mKT5Q4MD7Q07VA6W21VU8BhhJlTWZPF6Odaebg== X-Google-Smtp-Source: ABdhPJzNI5rZP+0cE6ERBwwO6M/irzlG55lt0fLR71elVSEQ1pnfE1Q0iK93QWQVllwfvZZRwqQCJoNxOCZqI/TCsA0= X-Received: by 2002:a67:2d06:: with SMTP id t6mr3634699vst.16.1616512319218; Tue, 23 Mar 2021 08:11:59 -0700 (PDT) MIME-Version: 1.0 References: <87zgyvtkd8.fsf@miraculix.mork.no> <323555.1616462233@turing-police> In-Reply-To: From: Gidi Gal Date: Tue, 23 Mar 2021 17:11:46 +0200 Message-ID: Subject: Re: How to switch between installed kernel and developed kernel To: Aruna Hewapathirane , valdis.kletnieks@vt.edu, kernelnewbies@kernelnewbies.org X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============6404359963063061094==" Errors-To: kernelnewbies-bounces@kernelnewbies.org --===============6404359963063061094== Content-Type: multipart/alternative; boundary="0000000000008fe80405be359a25" --0000000000008fe80405be359a25 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thanks Aruna and Valdis for your replies. Use : linux-check-removal > I tried to use it on my kernel. It did not seem to work - I still see the files in /boot. I assume it is because my kernel is not signed properly. When I launch "dpkg --list | grep linux-image" I don't see my kernel in the list. When I reboot I still get an "invalid signature" error. I attach the build log, install log and .config file and x509.genkey file in this link in Google Drive (I tried attaching the files to the mail and got a message saying there's an issue with their size). Please let me know what additional input can help to analyze this issue. Seriously - if you're not comfortable with that level of sysadmin > procedures, > maybe you shouldn't be a kernel hacker... > Once you are comfortable with compiling + linking/building +running a > custom kernel > what is preventing you from writing 'your own command' to do exactly that > ? Say a bash > script ? Or Python program ? > I gave up for now and prepared bash script for removing the files, based on the information in https://www.cyberciti.biz/faq/debian-redhat-linux-delete-kernel-command/ (see "A note about custom compiled Linux kernel" section). In my opinion, if Makefile supports install, it should support uninstall as well. Please let me know whether it sounds like a worthy enhancement or a wrong expectation. Aruna, thank you for your kind words. I promise not to be discouraged. Continuing with my quest to become a kernel developer :-) Thanks, Gidi On Tue, Mar 23, 2021 at 6:29 AM Aruna Hewapathirane < aruna.hewapathirane@gmail.com> wrote: > On Mon, Mar 22, 2021 at 9:17 PM Valdis Kl=C4=93tnieks > wrote: > >> On Tue, 23 Mar 2021 00:01:22 +0200, Gidi Gal said: >> >> > Many thanks for your reply, Aruna. Is there a way to remove the >> installed >> > '5.12.0-rc3-GIDI_DEV+' kernel ? > > > Yes there are 'many' ways to remove a kernel :-) > > A reverse command for the 'sudo make >> > modules_install install' command ? I found this link which explains ho= w >> to >> > do it manually ( >> > >> https://www.cyberciti.biz/faq/debian-redhat-linux-delete-kernel-command/ >> ), >> > I wonder if there is a safer way. >> > > Type linux into your shell then press the 'tab' key twice.. you will see = a > list of commands. > > Use : linux-check-removal > > Once you are comfortable with compiling + linking/building +running a > custom kernel > what is preventing you from writing 'your own command' to do exactly that > ? Say a bash > script ? Or Python program ? > > >> I can't speak for Debian, but I've used both the RedHat rpm method and >> just >> using the 'rm' command for self-bullt kernels since the 2.5.47 kernel or >> so >> (Egads, that was November 2002). As long as you follow the directions, >> you >> should be OK. 'rm' can get dangerous if you get over-exuberant with >> using '*' >> characters, but you already knew that, right? :) >> > > If you have to use rm always use it with the -i flag. Always prompt befor= e > removal. > > >> And if you followed my recommendation and back up /boot, you'll be all >> set to restore whatever you mess up. > > > Listen to Valdis in this case and follow orders religioulsy. Back up not > just /boot but anything > and everything that is important for you. > > >> The running kernel will work just fine >> as long as you don't reboot. And unless you did 'rm /boot/*', you should >> have >> at least one usable kernel left... >> >> Seriously - if you're not comfortable with that level of sysadmin >> procedures, >> maybe you shouldn't be a kernel hacker... > > > Do not listen to Valdis in this case as we were all newbies at one time > like Dan Carpenter told me > which I will remember to my dying day. Do not let anyone tell you what yo= u > can or cannot do when it > come's to the kernel because believe me like me you will find out over > time the kernel is a living thing that > has very subtle ways of informing you when you did something and it is no= t > happy :-) > > So compile away to your hearts content and go ahead and break things like > I did that is actually a very good way to learn. > And listen to more experienced folk like Valdis who probably knows more > about all the subsystems than anyone. But if anyone tells you > you should not be a kernel hacker then prove them wrong ? Actually that i= s > Valdis's way of motivating you. > > So good luck and we are here if you have questions :-) > > there is always the possibility of >> something you didn't know about trashing your system. See >> 5.12.0-rc1-dontuse >> for a nasty bug with file-backed swap that would stomp all over a sectio= n >> of your >> filesystem, and there was an ext[34] (can't remember anymore) bug during >> 2.5 >> that would trash the filesystem when you *unmounted* it. So you could >> boot the >> new kernel for testing, shutdown and boot the older version, and find it >> won't boot and be blaming the older version until we figured out what wa= s >> happening. :) >> >> But seriously - if you have a good backup of the system, and an bootable >> external image that you can use for rescue, there's not much a kernel >> screw-up >> can do to permanently lose date. >> > > Agreed 110%. > >> >> Of course, WIndows Update is at that same level of reliability, so >> "knowing how >> to recover a trashed system" is an important skill no matter what OS you >> run :) >> > > Hope this helps - Aruna > --0000000000008fe80405be359a25 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thanks Aruna and Valdis for your replies.

Use : linux-check-removal <uname-r of your kernel to r= emove>

I tried to use it on my kernel. It did not seem to work - I still see the files in /boot. I assume it is because my kernel is not signed=20 properly. When I launch "dpkg --list | grep linux-image" I don't=C2=A0<= span style=3D"font-family:arial,sans-serif">see my kernel in the list. When I reboot I still get an "invalid signatur= e" error. I attach the build log, install log and .config file and=20 x509.genkey file in this link in Google Drive (= I tried attaching the files to the mail and got a message saying there'= s an issue with their size). Please let me know what additional input can h= elp to=20 analyze this issue.

Seriously - if you're = not comfortable with that level of sysadmin procedures,
maybe you shouldn't be a kernel hacker...

Once you ar= e comfortable with compiling + linking/building +running a custom kernel
what is preventing you from writing 'your own command' to d= o exactly that ? Say a bash
script ? Or Python program ?=C2=A0

I gave up for now and pre= pared bash script for removing the files, based on the information in https://www.cyberciti.biz/faq/debian-redhat-linux-de= lete-kernel-command/ (see "A note about custom compiled Linux kernel" section). In my= =20 opinion, if Makefile supports install, it should support uninstall as=20 well. Please let me know whether it sounds like a worthy enhancement or a wrong expectation.

Aruna, thank you for your kind= words. I promise not to be discouraged. Continuing with my quest to become= a kernel developer :-)

Thanks,
Gidi=

On Tue, Mar 23, 2021 at 6:29 AM Aruna Hewapathirane <aruna.hewapathirane@gmail.com> w= rote:
O= n Mon, Mar 22, 2021 at 9:17 PM Valdis Kl=C4=93tnieks <valdis.kletnieks@vt.edu> = wrote:
On Tue, 2= 3 Mar 2021 00:01:22 +0200, Gidi Gal said:

> Many thanks for your reply, Aruna. Is there a way to remove the instal= led
> '5.12.0-rc3-GIDI_DEV+' kernel ?

Yes there are 'many' ways to remove a kernel :-)

=
A reverse command f= or the 'sudo make
> modules_install install' command ? I found this link which explain= s how to
> do it manually (
> https://www.cyberciti.b= iz/faq/debian-redhat-linux-delete-kernel-command/),
> I wonder if there is a safer way.

= Type linux into your shell then press the 'tab' key twice.. you wil= l see a list of commands.

Use : linux-check-re= moval <uname-r of your kernel to remove>
Once you are comfortable with compiling + linking/building +run= ning a custom kernel
what is preventing you from writing 'you= r own command' to do exactly that ? Say a bash
script ? Or Py= thon program ?=C2=A0
=C2=A0
I can't speak for Debian, but I've used both the RedHat rpm method = and just
using the 'rm' command for self-bullt kernels since the 2.5.47 kern= el or so
(Egads, that was November 2002).=C2=A0 As long as you follow the directions= , you
should be OK.=C2=A0 'rm' can get dangerous if you get over-exuberan= t with using '*'
characters, but you already knew that, right? :)

<= /div>
If you have to use rm always use it with the -i flag. Always prom= pt before removal.
=C2=A0
And if you followed my recommendation and back up /boot, you'll be all<= br> set to restore whatever you mess up.=C2=A0

Listen to Valdis in this case and follow orders religioulsy. Back up not j= ust /boot but anything
and everything that is important for you.
=C2=A0
The = running kernel will work just fine
as long as you don't reboot. And unless you did 'rm /boot/*', y= ou should have
at least one usable kernel left...

Seriously - if you're not comfortable with that level of sysadmin proce= dures,
maybe you shouldn't be a kernel hacker...

<= div>Do not listen to Valdis in this case as we were all newbies at one time= like Dan Carpenter told me
which I will remember to my dying day= . Do not let anyone tell you what you can or cannot do when it
co= me's to the kernel because believe me like me you will find out over ti= me the kernel is a living thing that
has very subtle ways of info= rming you when you did something and it is not happy :-)

So compile= away to your hearts content and go ahead and break things like I did that = is actually a very good way to learn.
And listen to more exp= erienced folk like Valdis who probably knows more about all the subsystems = than anyone. But if anyone tells you
you should not be a ker= nel hacker then prove them wrong ? Actually that is Valdis's way of mot= ivating you.

So good luck and we are here if you h= ave questions :-)

there is always the possibility of
something you didn't know about trashing your system.=C2=A0 See 5.12.0-= rc1-dontuse
for a nasty bug with file-backed swap that would stomp all over a section o= f your
filesystem, and there was an ext[34] (can't remember anymore) bug durin= g 2.5
that would trash the filesystem when you *unmounted* it.=C2=A0 So you could= boot the
new kernel for testing, shutdown and boot the older version, and find it won't boot and be blaming the older version until we figured out what w= as
happening. :)

But seriously - if you have a good backup of the system, and an bootable external image that you can use for rescue, there's not much a kernel s= crew-up
can do to permanently lose date.

Agreed= 110%.

Of course, WIndows Update is at that same level of reliability, so "kn= owing how
to recover a trashed system" is an important skill no matter what OS y= ou run :)

=C2=A0Hope this helps - Arun= a
--0000000000008fe80405be359a25-- --===============6404359963063061094== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies --===============6404359963063061094==--