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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, 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 F21E5C4332D for ; Mon, 28 Dec 2020 16:13:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D94C820829 for ; Mon, 28 Dec 2020 16:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733023AbgL1NTw (ORCPT ); Mon, 28 Dec 2020 08:19:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:48382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728256AbgL1NTr (ORCPT ); Mon, 28 Dec 2020 08:19:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E0B34207F7; Mon, 28 Dec 2020 13:19:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609161546; bh=0aLngOLlZjpxpVbTroKiMfMr9Wb/XUWSAoNOcIe9ss8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zaf/EMljKigwOEqpiykrasLTQtyUd/uTnTdRy2mtSG29pYpzvGgUFbxdJ7su+JwDE XTFP3Q/0t0lmLvM8CVLV8WTjkg2PpctgP/4N5vUKHRJkb5mxB0sKMOzPy5oQDKL/Ov qy0HxiEiIzoCbI4usJRttCVJkmVoXXe+fX8Vwyj8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jubin Zhong , Bjorn Helgaas Subject: [PATCH 4.14 242/242] PCI: Fix pci_slot_release() NULL pointer dereference Date: Mon, 28 Dec 2020 13:50:47 +0100 Message-Id: <20201228124916.602815383@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124904.654293249@linuxfoundation.org> References: <20201228124904.654293249@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: Jubin Zhong commit 4684709bf81a2d98152ed6b610e3d5c403f9bced upstream. If kobject_init_and_add() fails, pci_slot_release() is called to delete slot->list from parent->slots. But slot->list hasn't been initialized yet, so we dereference a NULL pointer: Unable to handle kernel NULL pointer dereference at virtual address 00000000 ... CPU: 10 PID: 1 Comm: swapper/0 Not tainted 4.4.240 #197 task: ffffeb398a45ef10 task.stack: ffffeb398a470000 PC is at __list_del_entry_valid+0x5c/0xb0 LR is at pci_slot_release+0x84/0xe4 ... __list_del_entry_valid+0x5c/0xb0 pci_slot_release+0x84/0xe4 kobject_put+0x184/0x1c4 pci_create_slot+0x17c/0x1b4 __pci_hp_initialize+0x68/0xa4 pciehp_probe+0x1a4/0x2fc pcie_port_probe_service+0x58/0x84 driver_probe_device+0x320/0x470 Initialize slot->list before calling kobject_init_and_add() to avoid this. Fixes: 8a94644b440e ("PCI: Fix pci_create_slot() reference count leak") Link: https://lore.kernel.org/r/1606876422-117457-1-git-send-email-zhongjubin@huawei.com Signed-off-by: Jubin Zhong Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Greg Kroah-Hartman --- drivers/pci/slot.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/pci/slot.c +++ b/drivers/pci/slot.c @@ -307,6 +307,9 @@ placeholder: goto err; } + INIT_LIST_HEAD(&slot->list); + list_add(&slot->list, &parent->slots); + err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, "%s", slot_name); if (err) { @@ -314,9 +317,6 @@ placeholder: goto err; } - INIT_LIST_HEAD(&slot->list); - list_add(&slot->list, &parent->slots); - down_read(&pci_bus_sem); list_for_each_entry(dev, &parent->devices, bus_list) if (PCI_SLOT(dev->devfn) == slot_nr)