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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DC51C433EF for ; Tue, 9 Nov 2021 01:03:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0841261A0A for ; Tue, 9 Nov 2021 01:03:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239292AbhKIBFu (ORCPT ); Mon, 8 Nov 2021 20:05:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:33040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237836AbhKIBEU (ORCPT ); Mon, 8 Nov 2021 20:04:20 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7035D61989; Tue, 9 Nov 2021 01:01:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636419690; bh=TOjlPrRJfj9axhzhp0RKU2dhlU5V9dASr+ThzNajcqA=; h=From:To:Cc:Subject:Date:From; b=GZtDjNuLYIZCeFDOMvhR+zDaOEd89Zvg1+3U3F1UkGwi70be5rk5wx46le9pfP3US LXLrtIc26wOfLC+UoQN5WeKJO8K/LFnBb5chA9uHC1wxxUBJnVH1l5MueTzYxkxEeb mqoBpnCW2voXMVBOcVP0xR69jFjE3lMFpi94lSf0bOIOm1s+40X+NpR50v5Cojox5z 1PGhPyssyEdN1FC5xbK7/DDcOh6UMjWXzIB4dIReojP+7oFDzSTtiXxHX9UnZl3Nl5 7LB6ZLjH2MUd3xFzSPHWmbOyl5Zod03xG6ayUYgxK3H8sJYWv9D/LO5vxhjIz2CWZV zHf2/vDDbPaUA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Charan Teja Reddy , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sasha Levin , sumit.semwal@linaro.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org Subject: [PATCH AUTOSEL 5.14 001/138] dma-buf: WARN on dmabuf release with pending attachments Date: Mon, 8 Nov 2021 12:44:27 -0500 Message-Id: <20211108174644.1187889-1-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Charan Teja Reddy [ Upstream commit f492283b157053e9555787262f058ae33096f568 ] It is expected from the clients to follow the below steps on an imported dmabuf fd: a) dmabuf = dma_buf_get(fd) // Get the dmabuf from fd b) dma_buf_attach(dmabuf); // Clients attach to the dmabuf o Here the kernel does some slab allocations, say for dma_buf_attachment and may be some other slab allocation in the dmabuf->ops->attach(). c) Client may need to do dma_buf_map_attachment(). d) Accordingly dma_buf_unmap_attachment() should be called. e) dma_buf_detach () // Clients detach to the dmabuf. o Here the slab allocations made in b) are freed. f) dma_buf_put(dmabuf) // Can free the dmabuf if it is the last reference. Now say an erroneous client failed at step c) above thus it directly called dma_buf_put(), step f) above. Considering that it may be the last reference to the dmabuf, buffer will be freed with pending attachments left to the dmabuf which can show up as the 'memory leak'. This should at least be reported as the WARN(). Signed-off-by: Charan Teja Reddy Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/1627043468-16381-1-git-send-email-charante@codeaurora.org Signed-off-by: Christian König Signed-off-by: Sasha Levin --- drivers/dma-buf/dma-buf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 511fe0d217a08..733c8b1c8467c 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -79,6 +79,7 @@ static void dma_buf_release(struct dentry *dentry) if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) dma_resv_fini(dmabuf->resv); + WARN_ON(!list_empty(&dmabuf->attachments)); module_put(dmabuf->owner); kfree(dmabuf->name); kfree(dmabuf); -- 2.33.0