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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 26E73C2BA19 for ; Wed, 15 Apr 2020 17:19:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F304F2076D for ; Wed, 15 Apr 2020 17:19:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404504AbgDORTP (ORCPT ); Wed, 15 Apr 2020 13:19:15 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:58952 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404387AbgDORTO (ORCPT ); Wed, 15 Apr 2020 13:19:14 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: andrzej.p) with ESMTPSA id C024F2A10E6 From: Andrzej Pietrasiewicz To: dri-devel@lists.freedsktop.org Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , James Qian Wang , "Gustavo A . R . Silva" , linux-next@vger.kernel.org, Emil Velikov , kernel@collabora.com Subject: [PATCH] drm: Don't free a struct never allocated by drm_gem_fb_init() Date: Wed, 15 Apr 2020 19:19:01 +0200 Message-Id: <20200415171901.23914-1-andrzej.p@collabora.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <202004150853.FD574CDD@keescook> References: <202004150853.FD574CDD@keescook> Sender: linux-next-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org drm_gem_fb_init() is passed the fb and never allocates it, so it should be not the one freeing it. As it is now the second call to kfree() is possible with the same fb. Coverity reported the following: *** CID 1492613: Memory - corruptions (USE_AFTER_FREE) /drivers/gpu/drm/drm_gem_framebuffer_helper.c: 230 in drm_gem_fb_create_with_funcs() 224 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 225 if (!fb) 226 return ERR_PTR(-ENOMEM); 227 228 ret = drm_gem_fb_init_with_funcs(dev, fb, file, mode_cmd, funcs); 229 if (ret) { vvv CID 1492613: Memory - corruptions (USE_AFTER_FREE) vvv Calling "kfree" frees pointer "fb" which has already been freed. [Note: The source code implementation of the function has been overridden by a user model.] 230 kfree(fb); 231 return ERR_PTR(ret); 232 } 233 234 return fb; 235 } drm_gem_fb_init_with_funcs() calls drm_gem_fb_init() drm_gem_fb_init() calls kfree(fb) Reported-by: coverity-bot Addresses-Coverity-ID: 1492613 ("Memory - corruptions") Fixes: f2b816d78a94 ("drm/core: Allow drivers allocate a subclass of struct drm_framebuffer") Signed-off-by: Andrzej Pietrasiewicz --- drivers/gpu/drm/drm_gem_framebuffer_helper.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c index cac15294aef6..ccc2c71fa491 100644 --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c @@ -76,10 +76,8 @@ drm_gem_fb_init(struct drm_device *dev, fb->obj[i] = obj[i]; ret = drm_framebuffer_init(dev, fb, funcs); - if (ret) { + if (ret) drm_err(dev, "Failed to init framebuffer: %d\n", ret); - kfree(fb); - } return ret; } -- 2.17.1