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[23.128.96.18]) by mx.google.com with ESMTP id dd3si3951418ejb.499.2020.09.19.00.29.50; Sat, 19 Sep 2020 00:30:13 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=R5iQRJEM; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726168AbgISH00 (ORCPT + 99 others); Sat, 19 Sep 2020 03:26:26 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:56377 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726041AbgISH0Z (ORCPT ); Sat, 19 Sep 2020 03:26:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600500384; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=UtdUjKgbLsYk0G9Z0ogGkq4Rldpk6SpW/fYzoloN9BI=; b=R5iQRJEMbC6EUZqsWV1vQzRr5FWTjPdwJg3W0U3hzbFGHmDLitCjffn+PoBqu5a75GT96p sydzfkQkAbOtdJzCTkoEWHGRc+ZcqqLQp8V8KMW8CK1GHmcQMqUAeiwrOSVWKXfkDslktT 9Pp2tN4d5XFE9IjSbqWyae2nawHF+DA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-346-oZxbG2zZP2WPWmUg0JdX4w-1; Sat, 19 Sep 2020 03:26:20 -0400 X-MC-Unique: oZxbG2zZP2WPWmUg0JdX4w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 56C75ACE22; Sat, 19 Sep 2020 07:26:19 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-66.pek2.redhat.com [10.72.12.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C142560CD1; Sat, 19 Sep 2020 07:26:16 +0000 (UTC) Date: Sat, 19 Sep 2020 15:26:13 +0800 From: Dave Young To: Andrew Morton Cc: bhe@redhat.com, Eric Biederman , 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: <20200919072613.GA3649@dhcp-128-65.nay.redhat.com> References: <20200918032546.GA4180@dhcp-128-65.nay.redhat.com> <20200918174743.0994c59f058451948837dcb6@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918174743.0994c59f058451948837dcb6@linux-foundation.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/18/20 at 05:47pm, Andrew Morton wrote: > On Fri, 18 Sep 2020 11:25:46 +0800 Dave Young 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? > I hope that commit can be merged in systemd, but we are really not optimize about that. The discussion is clear there but we did not get response since Aug 6. BTW, Kairui sent the systemd pull request 15 days ago, the new update added some comment. Thanks Dave