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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 4D269C38A2A for ; Fri, 8 May 2020 12:48:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C08421473 for ; Fri, 8 May 2020 12:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942134; bh=XE+FZXrzBDXXV9ixm2RSI3Bo3Ms8g3nmCf3qjbCYnIw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=elrlBPCQLAfUtyHE+1A/3RhMYY9Y53uDCMDhkckXzGKWjpOfH58KS0/gc2Pr44qS9 vt8JTszeGGAQmL6EmfPGtiJGoxNq4HZfRwbCdh8HorNwHLGLI+L/5841mGc0Sn5Plz t3iGa+BXzgdwUvuYb/A6FXk0ie/SOoHgzlas0OHI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729702AbgEHMsw (ORCPT ); Fri, 8 May 2020 08:48:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:53406 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729700AbgEHMsu (ORCPT ); Fri, 8 May 2020 08:48:50 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 49979206D6; Fri, 8 May 2020 12:48:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942130; bh=XE+FZXrzBDXXV9ixm2RSI3Bo3Ms8g3nmCf3qjbCYnIw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2S/AcPFbUvcOQdLaJjON3H8eD7RgmgrH5wz2LW4ptj18zDz5hWGkUwuqCZSPCznBG zdLo1ds18o3GX0bsdp89t0L8q1ZDmVakR3+tx+SesL3ISkQe7zOBeEQMuacFzNf/iE 0ZtcbGrC3ZzPd9thRBJCFPUZRsESzn1e2taoa324= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Fainelli , "David S. Miller" Subject: [PATCH 4.4 308/312] net: ep93xx_eth: Do not crash unloading module Date: Fri, 8 May 2020 14:34:59 +0200 Message-Id: <20200508123146.174409141@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123124.574959822@linuxfoundation.org> References: <20200508123124.574959822@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Fainelli commit c823abac17926767fb50175e098f087a6ac684c3 upstream. When we unload the ep93xx_eth, whether we have opened the network interface or not, we will either hit a kernel paging request error, or a simple NULL pointer de-reference because: - if ep93xx_open has been called, we have created a valid DMA mapping for ep->descs, when we call ep93xx_stop, we also call ep93xx_free_buffers, ep->descs now has a stale value - if ep93xx_open has not been called, we have a NULL pointer for ep->descs, so performing any operation against that address just won't work Fix this by adding a NULL pointer check for ep->descs which means that ep93xx_free_buffers() was able to successfully tear down the descriptors and free the DMA cookie as well. Fixes: 1d22e05df818 ("[PATCH] Cirrus Logic ep93xx ethernet driver") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/cirrus/ep93xx_eth.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/ethernet/cirrus/ep93xx_eth.c +++ b/drivers/net/ethernet/cirrus/ep93xx_eth.c @@ -468,6 +468,9 @@ static void ep93xx_free_buffers(struct e struct device *dev = ep->dev->dev.parent; int i; + if (!ep->descs) + return; + for (i = 0; i < RX_QUEUE_ENTRIES; i++) { dma_addr_t d; @@ -490,6 +493,7 @@ static void ep93xx_free_buffers(struct e dma_free_coherent(dev, sizeof(struct ep93xx_descs), ep->descs, ep->descs_dma_addr); + ep->descs = NULL; } static int ep93xx_alloc_buffers(struct ep93xx_priv *ep)