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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC7AFC4332F for ; Sun, 29 Oct 2023 23:20:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231923AbjJ2XUW (ORCPT ); Sun, 29 Oct 2023 19:20:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231668AbjJ2XUK (ORCPT ); Sun, 29 Oct 2023 19:20:10 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 381CE7692 for ; Sun, 29 Oct 2023 16:04:21 -0700 (PDT) Received: from workpc.. (109-252-153-31.dynamic.spd-mgts.ru [109.252.153.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id 546C36607396; Sun, 29 Oct 2023 23:02:58 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1698620579; bh=8rtXn19fvaBXhb48S1Y4vYdXdzNTfF4j95pl2pB4Jj8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MRGBZwF1NKhPQjB1XQlhRcOVPXHE84vqpNBhZrkK8krkrkiczEXKlHJqJFSt5Ww9A li5hV7sh/Zq/Gg8hOZjrbJ9jpEIg9QckJmNImb4IvRjWhWqpNpxAvikQCnNIelyYfe LBNNSlcea5YhZowelFyeGDaSya0NHk+bytBWQ1/1BxxYsUIgX7OHsQGKsMo+HFNH+s 71KYOKFuX8jktieetnuG3bIEH/j5eJOHRWcuFXlSBi1nt+QhKLXN+XqfN3fV7kTL8d JIwe/KHanbZO0DjJ6j6zPyZTADs7al9+xga2M3r83xbeXc/8hUodG7MCY27isI+Edj xQFYRgY+PCaug== From: Dmitry Osipenko To: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , =?UTF-8?q?Christian=20K=C3=B6nig?= , Qiang Yu , Steven Price , Boris Brezillon , Emma Anholt , Melissa Wen Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, virtualization@lists.linux-foundation.org Subject: [PATCH v18 22/26] drm/shmem-helper: Don't free refcounted GEM Date: Mon, 30 Oct 2023 02:02:01 +0300 Message-ID: <20231029230205.93277-23-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231029230205.93277-1-dmitry.osipenko@collabora.com> References: <20231029230205.93277-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't free refcounted shmem object to prevent use-after-free bug that is worse than a memory leak. Signed-off-by: Dmitry Osipenko --- drivers/gpu/drm/drm_gem_shmem_helper.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 6dd087f19ea3..4253c367dc07 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -203,9 +203,10 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) if (obj->import_attach) drm_prime_gem_destroy(obj, shmem->sgt); - drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)); - drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)); - drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count)); + if (drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)) || + drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)) || + drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count))) + return; drm_gem_object_release(obj); kfree(shmem); -- 2.41.0