From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 90D9FC433E5 for ; Sun, 19 Jul 2020 15:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D8A1208B3 for ; Sun, 19 Jul 2020 15:52:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fudan.edu.cn header.i=@fudan.edu.cn header.b="V2x5CcAb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbgGSPwU (ORCPT ); Sun, 19 Jul 2020 11:52:20 -0400 Received: from mail.fudan.edu.cn ([202.120.224.73]:53936 "EHLO fudan.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726024AbgGSPwT (ORCPT ); Sun, 19 Jul 2020 11:52:19 -0400 X-Greylist: delayed 368 seconds by postgrey-1.27 at vger.kernel.org; Sun, 19 Jul 2020 11:52:18 EDT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fudan.edu.cn; s=dkim; h=Received:Date:From:To:Cc:Subject: Message-ID:MIME-Version:Content-Type:Content-Disposition: Content-Transfer-Encoding; bh=nLgoWePWpiGRb9MQLcDy7kVpH9lYYEUHpm +ppMx20Fc=; b=V2x5CcAbYVxuE1BKBUl7fMe39rKDy2n2vkeMYT3NzlPFht9v3n Zcvtb3NAl/a8BeD8oktsga0a9lxDUQE86jqGfsjQj3gJWmJF/ks/0d3tZICg57F8 djnO3voddKoUdWRp0OQQZEdOj/QRQ7bZlnXFfJgiTXSaBRrlixPrwbQEI= Received: from xin-virtual-machine (unknown [111.192.165.241]) by app2 (Coremail) with SMTP id XQUFCgCHjLypahRfupwJAg--.48S3; Sun, 19 Jul 2020 23:45:48 +0800 (CST) Date: Sun, 19 Jul 2020 23:45:45 +0800 From: Xin Xiong To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: yuanxzhang@fudan.edu.cn, Xiyu Yang , Xin Tan , Xin Xiong Subject: [PATCH] drm: fix drm_dp_mst_port refcount leaks in drm_dp_mst_allocate_vcpi Message-ID: <20200719154545.GA41231@xin-virtual-machine> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit X-CM-TRANSID: XQUFCgCHjLypahRfupwJAg--.48S3 X-Coremail-Antispam: 1UD129KBjvJXoW7ZFWktF47Cr17JrW5ZFyDGFg_yoW8CF1xpF W7Kryjvr9Yva1Dta1Uu3WkCr4kuanFvF1xJrWUCw17u34Utr1FqF15Gw1aqFy7ArWxtFyF qanFkF48CF129aDanT9S1TB71UUUUUDqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIF xwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUAVWUtwCY02Avz4vE14v_Xr Wl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWU JVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7V AKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWrJr0_WFyUJwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfU8fHUUUUU U X-CM-SenderInfo: arytiiqsuqiimz6i3vldqovvfxof0/ Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org drm_dp_mst_allocate_vcpi() invokes drm_dp_mst_topology_get_port_validated(), which increases the refcount of the "port". These reference counting issues take place in two exception handling paths separately. Either when “slots” is less than 0 or when drm_dp_init_vcpi() returns a negative value, the function forgets to reduce the refcnt increased drm_dp_mst_topology_get_port_validated(), which results in a refcount leak. Fix these issues by pulling up the error handling when "slots" is less than 0, and calling drm_dp_mst_topology_put_port() before termination when drm_dp_init_vcpi() returns a negative value. Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: Xin Xiong --- drivers/gpu/drm/drm_dp_mst_topology.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 1e26b89628f9..97b48b531ec6 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -4261,11 +4261,11 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, { int ret; - port = drm_dp_mst_topology_get_port_validated(mgr, port); - if (!port) + if (slots < 0) return false; - if (slots < 0) + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) return false; if (port->vcpi.vcpi > 0) { @@ -4281,6 +4281,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, if (ret) { DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), ret); + drm_dp_mst_topology_put_port(port); goto out; } DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n", -- 2.25.1