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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 AB112C6379B for ; Mon, 19 Jul 2021 17:59:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9581B6113B for ; Mon, 19 Jul 2021 17:59:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378051AbhGSRRW (ORCPT ); Mon, 19 Jul 2021 13:17:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:35028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245183AbhGSPkZ (ORCPT ); Mon, 19 Jul 2021 11:40:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8EE4C61248; Mon, 19 Jul 2021 16:20:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711624; bh=8s8TEK/Xbj+pB8AdCTlyVxz3O5KUi40VYYY3jTVFzuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V/AREUTdkmO1KqlBg8aPYdnoFZGnucXJ5YLePbojcBG6fO8L3ci8VZ5Isc/DnrzvP JR1tqjEQO0xXoFP9eNq/V1HkUgl0j0ePhIInO0AlurhGvli8brQNL7WZewtqAhbt0J VyIc7vdNy8paDJCs0x6JZJrdartcIp0NBvJOqQYc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tong Zhang , Sasha Levin Subject: [PATCH 5.12 044/292] misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge Date: Mon, 19 Jul 2021 16:51:46 +0200 Message-Id: <20210719144943.957542690@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144942.514164272@linuxfoundation.org> References: <20210719144942.514164272@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: Tong Zhang [ Upstream commit 3ce3e45cc333da707d4d6eb433574b990bcc26f5 ] There is an issue with the ASPM(optional) capability checking function. A device might be attached to root complex directly, in this case, bus->self(bridge) will be NULL, thus priv->parent_pdev is NULL. Since alcor_pci_init_check_aspm(priv->parent_pdev) checks the PCI link's ASPM capability and populate parent_cap_off, which will be used later by alcor_pci_aspm_ctrl() to dynamically turn on/off device, what we can do here is to avoid checking the capability if we are on the root complex. This will make pdev_cap_off 0 and alcor_pci_aspm_ctrl() will simply return when bring called, effectively disable ASPM for the device. [ 1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0 [ 1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40 [ 1.253998] Call Trace: [ 1.254131] ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci] [ 1.254476] alcor_pci_probe+0x169/0x2d5 [alcor_pci] Co-developed-by: Greg Kroah-Hartman Signed-off-by: Tong Zhang Link: https://lore.kernel.org/r/20210513040732.1310159-1-ztong0001@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/cardreader/alcor_pci.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/misc/cardreader/alcor_pci.c b/drivers/misc/cardreader/alcor_pci.c index cd402c89189e..0a62307f7ffb 100644 --- a/drivers/misc/cardreader/alcor_pci.c +++ b/drivers/misc/cardreader/alcor_pci.c @@ -139,7 +139,13 @@ static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv) u32 val32; priv->pdev_cap_off = alcor_pci_find_cap_offset(priv, priv->pdev); - priv->parent_cap_off = alcor_pci_find_cap_offset(priv, + /* + * A device might be attached to root complex directly and + * priv->parent_pdev will be NULL. In this case we don't check its + * capability and disable ASPM completely. + */ + if (!priv->parent_pdev) + priv->parent_cap_off = alcor_pci_find_cap_offset(priv, priv->parent_pdev); if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) { -- 2.30.2