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Sun, 1 Nov 2026 20:09:06 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.2]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A19F51800495; Sun, 1 Nov 2026 20:09:05 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 4DC7821E6A04; Sun, 01 Nov 2026 21:09:03 +0100 (CET) Resent-To: michael.roth@amd.com, richard.henderson@linaro.org, qemu-devel@nongnu.org, philmd@oss.qualcomm.com, pierrick.bouvier@oss.qualcomm.com, farosas@suse.de, dave@treblig.org Resent-From: Markus Armbruster Resent-Date: Sun, 01 Nov 2026 21:09:03 +0100 Resent-Message-ID: <87v76g1fhc.fsf@pond.sub.org> From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: qemu-devel@nongnu.org, =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Michael Roth , Philippe =?utf-8?Q?Mathieu-Daud?= =?utf-8?Q?=C3=A9?= , Fabiano Rosas , Richard Henderson , "Dr. David Alan Gilbert" , Paolo Bonzini , Pierrick Bouvier , Eric Blake , Laurent Vivier Subject: Re: [PATCH 07/21] util: introduce 'tldr', a system data recorder for crash handling In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Thu, 29 Oct 2026 15:35:05 +0000") References: <20261015112044.1999748-1-berrange@redhat.com> <20261015112044.1999748-8-berrange@redhat.com> <87ecd8gba1.fsf@pond.sub.org> Date: Fri, 30 Oct 2026 09:59:53 +0100 Message-ID: <87tsm3a7hy.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 5 X-Spam_score: 0.5 X-Spam_bar: / X-Spam_report: (0.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Daniel P. Berrang=C3=A9 writes: > On Thu, Oct 29, 2026 at 09:29:26AM +0100, Markus Armbruster wrote: >> Daniel P. Berrang=C3=A9 writes: >>=20 >> > Introduce a new subsystem "tldr" aka "thrifty live data recorder" >> > that will be able to continuously collect certain information at >> > runtime and dump that in a crash report when QEMU exits abnormally. >> > As a second use case, it will support manual triggering on interesting >> > events such as guest OS panic. >>=20 >> What's manual about that? > > Manual in the sense that the mgmt app has to explicitly request > the data recorder contents when a guest OS panics, vs automatic > dump when QEMU dies with a fatal signal. Suggest to clarify like this: "it lets a management application dump it manually, say when it received an interesting event such as GUEST_PANICKED." >> > diff --git a/qapi/qom.json b/qapi/qom.json >> > index 49f222796ab..1c9031fba9a 100644 >> > --- a/qapi/qom.json >> > +++ b/qapi/qom.json >> > @@ -1233,6 +1233,19 @@ >> > 'data': { '*pretty': 'bool', >> > '*close-action': 'MonitorQMPCloseAction' } } >> >=20=20 >> > +## >> > +# @QTLDRConfigProperties: >> > +# Configuration for data recorder >> > +# >> > +# @crash-target: fully qualified path to perserve data recorder >> > +# contents on QEMU crash >>=20 >> What's a "fully qualified path"? >>=20 >> Do you mean what POSIX calls "absolute pathname"? > > Yes. Let's use that term then. [...]