Hi Konrad,
On Mon, 21 Sep 2020 16:18:12 -0400 Konrad Rzeszutek Wilk <konrad.w...@oracle.com> wrote: > On Fri, Sep 18, 2020 at 05:47:43PM -0700, Andrew Morton wrote: > > On Fri, 18 Sep 2020 11:25:46 +0800 Dave Young <dyo...@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). > > Perhaps it may be better to fix the issus on s390x and PowerPC as well? There's little s390 can fix. We use the panic_notifier_list to start other dumpers in case kdump isn't configured or failed. This behavior was introduced in 2006 long before crash_kexec_post_notifiers were introduced. So I suggest that crash_kexec_post_notifiers are fixed instead. > > > > > > 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? > > It does in systemd, but there is a strong interest in making this on by > default. AFAIK pstore requires UEFI to work. So what's the point to enable it on non-UEFI systems? Thanks Philipp
