From patchwork Wed Aug 18 13:02:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wentao_Liang X-Patchwork-Id: 12444899 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 A693EC432BE for ; Wed, 18 Aug 2021 17:40:36 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 5F54B610FE for ; Wed, 18 Aug 2021 17:40:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5F54B610FE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=163.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2F36A6E888; Wed, 18 Aug 2021 17:40:28 +0000 (UTC) X-Greylist: delayed 942 seconds by postgrey-1.36 at gabe; Wed, 18 Aug 2021 13:20:06 UTC Received: from mail-m971.mail.163.com (mail-m971.mail.163.com [123.126.97.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9C4176E5AB for ; Wed, 18 Aug 2021 13:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=1ty22 VOMwZz6zNP9VFFtEN/bLi/9Opdu0wufpsZYxvU=; b=i7B4+rwLQ+mjFUw+4LiCg wuTOwj4+GIIggPwv/s+CqaBR5YrmzueXWvpchOZeltR7OomoWEgxjXu46GIz/Nga ukQC0qXZ0dOA3Quo59Pt0Ywa3h5QiIWMzHlplguIbLNAWJjdyLv6sP2XreKZZuzD EwMhX7wwXVHfiayv6MqLZk= Received: from localhost.localdomain (unknown [111.201.47.26]) by smtp1 (Coremail) with SMTP id GdxpCgD3FkzqBB1hdtlmOA--.179S4; Wed, 18 Aug 2021 21:02:41 +0800 (CST) From: Wentao_Liang To: maarten.lankhorst@linux.intel.com Cc: mripard@kernel.org, tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch, sumit.semwal@linaro.org, christian.koenig@amd.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, Wentao_Liang Subject: [PATCH] drm/prime: fix a potential double put (release) bug Date: Wed, 18 Aug 2021 21:02:31 +0800 Message-Id: <20210818130231.3484-1-Wentao_Liang_g@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: GdxpCgD3FkzqBB1hdtlmOA--.179S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Kw4rGF4xWr43CrWDJr17Awb_yoW8Kr1fpF WYyFyUKrWUtF4jqFyfAF1kZan09w45Ga1xXrW3Jw4Yv3WFqr1DWF9rAr9Fyr15G34Dtw1S yFyUXry5JryUCF7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jkYFAUUUUU= X-Originating-IP: [111.201.47.26] X-CM-SenderInfo: xzhq3t5rboxtpqjbwqqrwthudrp/xtbBQhHyL1++M90j-wAAsd X-Mailman-Approved-At: Wed, 18 Aug 2021 17:40:22 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In line 317 (#1), drm_gem_prime_import() is called, it will call drm_gem_prime_import_dev(). At the end of the function drm_gem_prime_import_dev() (line 956, #2), "dma_buf_put(dma_buf);" puts dma_buf->file and may cause it to be released. However, after drm_gem_prime_import() returning, the dma_buf may be put again by the same put function in lines 342, 351 and 358 (#3, #4, #5). Putting the dma_buf improperly more than once can lead to an incorrect dma_buf- >file put. We believe that the put of the dma_buf in the function drm_gem_prime_import() is unnecessary (#2). We can fix the above bug by removing the redundant "dma_buf_put(dma_buf);" in line 956. 314 if (dev->driver->gem_prime_import) 315 obj = dev->driver->gem_prime_import(dev, dma_buf); 316 else 317 obj = drm_gem_prime_import(dev, dma_buf); //#1 call to drm_gem_prime_import // ->drm_gem_prime_import_dev // ->dma_buf_put ... 336 ret = drm_prime_add_buf_handle(&file_priv->prime, 337 dma_buf, *handle); ... 342 dma_buf_put(dma_buf); //#3 put again 343 344 return 0; 345 346 fail: 351 dma_buf_put(dma_buf); //#4 put again 352 return ret; 356 out_put: 357 mutex_unlock(&file_priv->prime.lock); 358 dma_buf_put(dma_buf); //#5 put again 359 return ret; 360 } 905 struct drm_gem_object *drm_gem_prime_import_dev (struct drm_device *dev, 906 struct dma_buf *dma_buf, 907 struct device *attach_dev) 908 { ... 952 fail_unmap: 953 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL); 954 fail_detach: 955 dma_buf_detach(dma_buf, attach); 956 dma_buf_put(dma_buf); //#2 the first put of dma_buf // (unnecessary) 957 958 return ERR_PTR(ret); 959 } Signed-off-by: Wentao_Liang --- drivers/gpu/drm/drm_prime.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 2a54f86856af..cef03ad0d5cd 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -953,7 +953,6 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev, dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL); fail_detach: dma_buf_detach(dma_buf, attach); - dma_buf_put(dma_buf); return ERR_PTR(ret); }