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Tue, 12 Mar 2024 06:26:41 -0700 (PDT) Received: from draig (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id F1D2E5F863; Tue, 12 Mar 2024 13:26:40 +0000 (GMT) From: =?utf-8?Q?Alex_Benn=C3=A9e?= To: Nicholas Piggin Cc: qemu-devel@nongnu.org, Pavel Dovgalyuk , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Richard Henderson , Paolo Bonzini , John Snow , Cleber Rosa , Wainer dos Santos Moschetta , Beraldo Leal , Michael Tokarev Subject: Re: [PATCH v4 04/24] replay: allow runstate shutdown->running when replaying trace In-Reply-To: <20240311174026.2177152-5-npiggin@gmail.com> (Nicholas Piggin's message of "Tue, 12 Mar 2024 03:40:06 +1000") References: <20240311174026.2177152-1-npiggin@gmail.com> <20240311174026.2177152-5-npiggin@gmail.com> User-Agent: mu4e 1.12.1; emacs 29.1 Date: Tue, 12 Mar 2024 13:26:40 +0000 Message-ID: <871q8fpomn.fsf@draig.linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::532; envelope-from=alex.bennee@linaro.org; helo=mail-ed1-x532.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Nicholas Piggin writes: > When replaying a trace, it is possible to go from shutdown to running > with a reverse-debugging step. This can be useful if the problem being > debugged triggers a reset or shutdown. > > This can be tested by making a recording of a machine that shuts down, > then using -action shutdown=3Dpause when replaying it. Continuing to the > end of the trace then reverse-stepping in gdb crashes due to invalid > runstate transition. > > Just permitting the transition seems to be all that's necessary for > reverse-debugging to work well in such a state. > > Reviewed-by: Pavel Dovgalyuk > Signed-off-by: Nicholas Piggin Reviewed-by: Alex Benn=C3=A9e --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro