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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 67F5FC433B4 for ; Mon, 17 May 2021 16:11:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48DC260E0C for ; Mon, 17 May 2021 16:11:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345462AbhEQQM5 (ORCPT ); Mon, 17 May 2021 12:12:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:36422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245503AbhEQPsm (ORCPT ); Mon, 17 May 2021 11:48:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8DEBE61951; Mon, 17 May 2021 14:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621262717; bh=ZMPdg8c/xRnNPF8aSdEzeYilHDUSfxsID6p4SkBLYVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1xLRsG3bCRV8iW7OvJudoXAvRHKNs5wZ6/q0qg4igm8LJtUNofAmluKRCxBBcAL9p 7PqxY27Lb1BU0XLgkt7opSlusyzKcVAsdGGw6SYFlBS4cBWmJEEZb6A1VGn7j3uhq7 gtteA6yPmd8i2hgmKIFtK7E3BVw0ct8c4qu6rGKY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lv Yunlong , Matthew Auld , Jani Nikula Subject: [PATCH 5.10 277/289] drm/i915/gt: Fix a double free in gen8_preallocate_top_level_pdp Date: Mon, 17 May 2021 16:03:22 +0200 Message-Id: <20210517140314.463780862@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140305.140529752@linuxfoundation.org> References: <20210517140305.140529752@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lv Yunlong commit ea995218dddba171fecd05496c69617c5ef3c5b8 upstream. Our code analyzer reported a double free bug. In gen8_preallocate_top_level_pdp, pde and pde->pt.base are allocated via alloc_pd(vm) with one reference. If pin_pt_dma() failed, pde->pt.base is freed by i915_gem_object_put() with a reference dropped. Then free_pd calls free_px() defined in intel_ppgtt.c, which calls i915_gem_object_put() to put pde->pt.base again. As pde->pt.base is protected by refcount, so the second put will not free pde->pt.base actually. But, maybe it is better to remove the first put? Fixes: 82adf901138cc ("drm/i915/gt: Shrink i915_page_directory's slab bucket") Signed-off-by: Lv Yunlong Reviewed-by: Matthew Auld Signed-off-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20210426124340.4238-1-lyl2019@mail.ustc.edu.cn (cherry picked from commit ac69496fe65cca0611d5917b7d232730ff605bc7) Signed-off-by: Jani Nikula Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 1 - 1 file changed, 1 deletion(-) --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c @@ -628,7 +628,6 @@ static int gen8_preallocate_top_level_pd err = pin_pt_dma(vm, pde->pt.base); if (err) { - i915_gem_object_put(pde->pt.base); free_pd(vm, pde); return err; }