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Date:   Fri, 18 Sep 2020 17:47:43 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Dave Young <dyoung@redhat.com>
Cc:     bhe@redhat.com, Eric Biederman <ebiederm@xmission.com>,
        linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH] Only allow to set crash_kexec_post_notifiers on boot
 time
Message-Id: <20200918174743.0994c59f058451948837dcb6@linux-foundation.org>
In-Reply-To: <20200918032546.GA4180@dhcp-128-65.nay.redhat.com>
References: <20200918032546.GA4180@dhcp-128-65.nay.redhat.com>
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On Fri, 18 Sep 2020 11:25:46 +0800 Dave Young <dyoung@redhat.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?