linux-kernel - Re: [PATCH] Only allow to set crash_kexec_post

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 18 Sep 2020 17:47:43 -0700
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Dave Young <dyoung@...hat.com>
Cc:     bhe@...hat.com, Eric Biederman <ebiederm@...ssion.com>,
        linux-kernel@...r.kernel.org, kexec@...ts.infradead.org
Subject: Re: [PATCH] Only allow to set crash_kexec_post_notifiers on boot
 time

On Fri, 18 Sep 2020 11:25:46 +0800 Dave Young <dyoung@...hat.com> wrote:

> crash_kexec_post_notifiers enables running various panic notifier
> before kdump kernel booting. This increases risks of kdump failure.
> It is well documented in kernel-parameters.txt. We do not suggest
> people to enable it together with kdump unless he/she is really sure.
> This is also not suggested to be enabled by default when users are
> not aware in distributions.
> 
> But unfortunately it is enabled by default in systemd, see below
> discussions in a systemd report, we can not convince systemd to change
> it:
> https://github.com/systemd/systemd/issues/16661
> 
> Actually we have got reports about kdump kernel hangs in both s390x
> and powerpcle cases caused by the systemd change,  also some x86 cases
> could also be caused by the same (although that is in Hyper-V code
> instead of systemd, that need to be addressed separately).
> 
> Thus to avoid the auto enablement here just disable the param writable
> permission in sysfs.
> 

Well.  I don't think this is at all a desirable way of resolving a
disagreement with the systemd developers

At the above github address I'm seeing "ryncsn added a commit to
ryncsn/systemd that referenced this issue 9 days ago", "pstore: don't
enable crash_kexec_post_notifiers by default".  So didn't that address
the issue?