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[2003:d3:6f12:5200:d4b0:7119:e720:e6da]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42e1ca1a396sm1704874f8f.22.2025.11.26.23.10.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Nov 2025 23:10:29 -0800 (PST) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id C34B421E6A27; Thu, 27 Nov 2025 08:10:28 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Cc: jmarcin@redhat.com, peterx@redhat.com, marcandre.lureau@redhat.com, farosas@suse.de, berrange@redhat.com, vsementsov@yandex-team.ru, mail@maciej.szmigiero.name, clg@redhat.com, peter.maydell@linaro.org Subject: [PATCH 2.5/6] error: Poison g_autoptr(Error) to prevent its use Date: Thu, 27 Nov 2025 08:10:28 +0100 Message-ID: <20251127071028.2745789-1-armbru@redhat.com> In-Reply-To: <20251125204648.857018-3-peterx@redhat.com> References: <20251125204648.857018-3-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-getmail-retrieved-from-mailbox: [Gmail]/All Mail X-GMAIL-LABELS: "\\Sent" X-GMAIL-THRID: 1849926541202783082 X-GMAIL-MSGID: 1849926541202783082 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.224, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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 The previous commit reverted support for g_autoptr(Error). This one should stop it from coming back. Suggested-by: Peter Maydell Signed-off-by: Markus Armbruster --- include/qapi/error.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/include/qapi/error.h b/include/qapi/error.h index f3ce4a4a2d..2356b84bb3 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -437,6 +437,26 @@ Error *error_copy(const Error *err); */ void error_free(Error *err); +/* + * Poison g_autoptr(Error) to prevent its use. + * + * Functions that report or propagate an error take ownership of the + * Error object. Explicit error_free() is needed when you handle an + * error in some other way. This is rare. + * + * g_autoptr(Error) would call error_free() automatically on return. + * To avoid a double-free, we'd have to manually clear the pointer + * every time we propagate or report. + * + * Thus, g_autoptr(Error) would make the rare case easier to get right + * (less prone to leaks), and the common case easier to get wrong + * (more prone to double-free). + */ +extern void +__attribute__((error("Do not use g_autoptr() to declare Error * variables"))) +error_free_poisoned(Error *err); +G_DEFINE_AUTOPTR_CLEANUP_FUNC(Error, error_free_poisoned) + /* * Convenience function to assert that *@errp is set, then silently free it. */ -- 2.49.0