From patchwork Tue Oct 20 07:44:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Luc Michel X-Patchwork-Id: 302544 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8843C433E7 for ; Tue, 20 Oct 2020 07:44:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6058B2224F for ; Tue, 20 Oct 2020 07:44:37 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Tue, 20 Oct 2020 03:43:40 -0400 Received: from sekoia-pc.home.lmichel.fr (sekoia-pc.home.lmichel.fr [192.168.61.100]) by pharaoh.lmichel.fr (Postfix) with ESMTPS id 1F895C60010; Tue, 20 Oct 2020 07:43:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lmichel.fr; s=pharaoh; t=1603179814; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references; bh=mlIRwhaHDHPVIU5gr1CK/VGLAMYhpYmFtsI2zoTsscE=; b=PEREai9yOngZf1GqKDJOEWjrdJaeX99Uer+pHaXjHCDv2TaPk5UmbUmA/O4tGsXF5pPzTC NHqqmlEHzKQLrG5N4fJqjSKE91WuOWluBpnuRLogbkqU2TnuJKWYhOT+vWzkLIna5gewM7 rcbej0puib9BcQJdid/wjf672RAc9+lqHz7XEO7RpAxorZ9s2hUlywQNo5VG4jkAKVQAkt gh9dSNlRchzltwiEgULN/BIEMsZHnE/DZp/3TIFCdgczXo5y08u7yTpDhR+p3Mf6uNLSfF 1fQ0Z/mFx7kUIr86HAl3WQl2Ez4zUq9U1wbofs+VZCrYS4LwXgOs5MH96TJiUA== From: Luc Michel To: qemu-devel@nongnu.org Subject: [PATCH] hw/core/qdev-clock: add a reference on aliased clocks Date: Tue, 20 Oct 2020 09:44:26 +0200 Message-Id: <20201020074426.105878-1-luc@lmichel.fr> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 ARC-Message-Signature: i=1; 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pharaoh.lmichel.fr Received-SPF: pass client-ip=149.202.28.74; envelope-from=luc@lmichel.fr; helo=pharaoh.lmichel.fr X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/20 03:43:34 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , Peter Maydell , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= , Eduardo Habkost , =?utf-8?q?Philippe_Mathieu-Dau?= =?utf-8?b?ZMOp?= , Paolo Bonzini , Luc Michel Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When aliasing a clock with the qdev_alias_clock() function, a new link property is created on the device aliasing the clock. The link points to the aliased clock and use the OBJ_PROP_LINK_STRONG flag. This property is read only since it does not provide a check callback for modifications. The object_property_add_link() documentation stats that with OBJ_PROP_LINK_STRONG properties, the linked object reference count get decremented when the property is deleted. But it is _not_ incremented on creation (object_property_add_link() does not actually know the link). This commit increments the reference count on the aliased clock to ensure the aliased clock stays alive during the property lifetime, and to avoid a double-free memory error when the property get deleted. Signed-off-by: Luc Michel Reviewed-by: Philippe Mathieu-Daudé --- hw/core/qdev-clock.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/core/qdev-clock.c b/hw/core/qdev-clock.c index 6a9a340d0f..5f5e143702 100644 --- a/hw/core/qdev-clock.c +++ b/hw/core/qdev-clock.c @@ -59,10 +59,11 @@ static NamedClockList *qdev_init_clocklist(DeviceState *dev, const char *name, } else { object_property_add_link(OBJECT(dev), name, object_get_typename(OBJECT(clk)), (Object **) &ncl->clock, NULL, OBJ_PROP_LINK_STRONG); + object_ref(OBJECT(clk)); } ncl->clock = clk; QLIST_INSERT_HEAD(&dev->clocks, ncl, node);