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 40A1FC43217 for ; Mon, 15 Nov 2021 19:27:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2735461A6C for ; Mon, 15 Nov 2021 19:27:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345101AbhKOT01 (ORCPT ); Mon, 15 Nov 2021 14:26:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:35666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238927AbhKORuk (ORCPT ); Mon, 15 Nov 2021 12:50:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E95C1632AA; Mon, 15 Nov 2021 17:31:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636997477; bh=xbBnIUX/zyaJx7lBhF4iyaKWUIKp0gzgpFILNaZqnwY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hvh/U99CQAnwX0ZPjyPk8idzXx83jL6oN7MD9VQgP79amLIPoletqWVqmV4d5Lj4p xr8z9Kk1ScsufHFatsaVKUOXrKrMTbB88lwepboxtJejnebXLSIAILTIfkne0PCkdy F+ekJZYLqUAWz27CH/MgXPSOne7lItLnrHMPMWi0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Charan Teja Reddy , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sasha Levin Subject: [PATCH 5.10 163/575] dma-buf: WARN on dmabuf release with pending attachments Date: Mon, 15 Nov 2021 17:58:08 +0100 Message-Id: <20211115165349.353529710@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165343.579890274@linuxfoundation.org> References: <20211115165343.579890274@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: 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 922416b3aaceb..93e9bf7382595 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