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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AF1EC6FD18 for ; Wed, 29 Mar 2023 15:13:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229694AbjC2PNO (ORCPT ); Wed, 29 Mar 2023 11:13:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229501AbjC2PNN (ORCPT ); Wed, 29 Mar 2023 11:13:13 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2754C2137; Wed, 29 Mar 2023 08:13:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680102792; x=1711638792; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=t475cyWqCFlyPGitqCQPmWBci8f4STxpuRWN3UOOnRo=; b=jpvBw2q8Q9UcPaak2SkFtO/omhZkMo5XjhdkzGTKLsstoz4McBWBfW20 /pyB2FTrngXw41zvu82WrtSQeYF3+PqGe3DKL5vKX9wM0KGLK21P1Wfth jmVCmYtaPT0SurhtP//oG/rLw/pzvUM5C+mBDyuLBj4mN5XGtqImqnFJY vHPln7MfUW277W6K4gXGJizgiV11Q+wPcJBnPD027F10qUZJ7DLU1VD3z WSsl9dvAC/FnnORG16ittuhS1VvyGN1OMBXCHfOqqmkAX7NeJU4HrYnR2 86Q23EpUXNuC5xzAFv1TzF8jajDn40Tbf68KcoqkRB2Sf1qYDXaDVDpDL Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="340924902" X-IronPort-AV: E=Sophos;i="5.98,301,1673942400"; d="scan'208";a="340924902" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 08:10:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="1014057021" X-IronPort-AV: E=Sophos;i="5.98,301,1673942400"; d="scan'208";a="1014057021" Received: from tinabao-mobl1.amr.corp.intel.com (HELO [10.209.80.72]) ([10.209.80.72]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 08:10:58 -0700 Message-ID: Date: Wed, 29 Mar 2023 08:10:57 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.9.0 Subject: Re: [PATCH] PCI: Fix use-after-free in pci_bus_release_domain_nr() Content-Language: en-US To: Rob Herring , Bjorn Helgaas , =?UTF-8?Q?Pali_Roh=c3=a1r?= Cc: Jon Hunter , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230329123835.2724518-1-robh@kernel.org> From: Sathyanarayanan Kuppuswamy In-Reply-To: <20230329123835.2724518-1-robh@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 3/29/23 5:38 AM, Rob Herring wrote: > Commit c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()") > introduced a use-after-free bug in the bus removal cleanup. The issue > was found with kfence: > > [ 19.285870] ================================================================== > [ 19.293351] BUG: KFENCE: use-after-free read in pci_bus_release_domain_nr+0x10/0x70 > > [ 19.302817] Use-after-free read at 0x000000007f3b80eb (in kfence-#115): > [ 19.309677] pci_bus_release_domain_nr+0x10/0x70 > [ 19.309691] dw_pcie_host_deinit+0x28/0x78 > [ 19.309702] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194] > [ 19.309734] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194] > [ 19.309752] platform_probe+0x90/0xd8 > [ 19.309764] really_probe+0xb8/0x298 > [ 19.309777] __driver_probe_device+0x78/0xd8 > [ 19.309788] driver_probe_device+0x38/0x120 > [ 19.309799] __device_attach_driver+0x94/0xe0 > [ 19.309812] bus_for_each_drv+0x70/0xc8 > [ 19.309822] __device_attach+0xfc/0x188 > [ 19.309833] device_initial_probe+0x10/0x18 > [ 19.309844] bus_probe_device+0x94/0xa0 > [ 19.309854] deferred_probe_work_func+0x80/0xb8 > [ 19.309864] process_one_work+0x1e0/0x348 > [ 19.309882] worker_thread+0x48/0x410 > [ 19.309891] kthread+0xf4/0x110 > [ 19.309904] ret_from_fork+0x10/0x20 > > [ 19.311457] kfence-#115: 0x00000000063a155a-0x00000000ba698da8, size=1072, cache=kmalloc-2k > > [ 19.311469] allocated by task 96 on cpu 10 at 19.279323s: > [ 19.311562] __kmem_cache_alloc_node+0x260/0x278 > [ 19.311571] kmalloc_trace+0x24/0x30 > [ 19.311580] pci_alloc_bus+0x24/0xa0 > [ 19.311590] pci_register_host_bridge+0x48/0x4b8 > [ 19.311601] pci_scan_root_bus_bridge+0xc0/0xe8 > [ 19.311613] pci_host_probe+0x18/0xc0 > [ 19.311623] dw_pcie_host_init+0x2c0/0x568 > [ 19.311630] tegra_pcie_dw_probe+0x610/0xb28 [pcie_tegra194] > [ 19.311647] platform_probe+0x90/0xd8 > [ 19.311653] really_probe+0xb8/0x298 > [ 19.311663] __driver_probe_device+0x78/0xd8 > [ 19.311672] driver_probe_device+0x38/0x120 > [ 19.311682] __device_attach_driver+0x94/0xe0 > [ 19.311694] bus_for_each_drv+0x70/0xc8 > [ 19.311702] __device_attach+0xfc/0x188 > [ 19.311713] device_initial_probe+0x10/0x18 > [ 19.311724] bus_probe_device+0x94/0xa0 > [ 19.311733] deferred_probe_work_func+0x80/0xb8 > [ 19.311743] process_one_work+0x1e0/0x348 > [ 19.311753] worker_thread+0x48/0x410 > [ 19.311763] kthread+0xf4/0x110 > [ 19.311771] ret_from_fork+0x10/0x20 > > [ 19.311782] freed by task 96 on cpu 10 at 19.285833s: > [ 19.311799] release_pcibus_dev+0x30/0x40 > [ 19.311808] device_release+0x30/0x90 > [ 19.311814] kobject_put+0xa8/0x120 > [ 19.311832] device_unregister+0x20/0x30 > [ 19.311839] pci_remove_bus+0x78/0x88 > [ 19.311850] pci_remove_root_bus+0x5c/0x98 > [ 19.311860] dw_pcie_host_deinit+0x28/0x78 > [ 19.311866] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194] > [ 19.311883] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194] > [ 19.311900] platform_probe+0x90/0xd8 > [ 19.311906] really_probe+0xb8/0x298 > [ 19.311916] __driver_probe_device+0x78/0xd8 > [ 19.311926] driver_probe_device+0x38/0x120 > [ 19.311936] __device_attach_driver+0x94/0xe0 > [ 19.311947] bus_for_each_drv+0x70/0xc8 > [ 19.311956] __device_attach+0xfc/0x188 > [ 19.311966] device_initial_probe+0x10/0x18 > [ 19.311976] bus_probe_device+0x94/0xa0 > [ 19.311985] deferred_probe_work_func+0x80/0xb8 > [ 19.311995] process_one_work+0x1e0/0x348 > [ 19.312005] worker_thread+0x48/0x410 > [ 19.312014] kthread+0xf4/0x110 > [ 19.312022] ret_from_fork+0x10/0x20 > > [ 19.313579] CPU: 10 PID: 96 Comm: kworker/u24:2 Not tainted 6.2.0 #4 > [ 19.320171] Hardware name: /, BIOS 1.0-d7fb19b 08/10/2022 > [ 19.325852] Workqueue: events_unbound deferred_probe_work_func > [ 19.331919] ================================================================== > > The stack trace is a bit misleading as dw_pcie_host_deinit() doesn't > directly call pci_bus_release_domain_nr(). The issue turns out to be in > pci_remove_root_bus() which first calls pci_remove_bus() which frees the > struct pci_bus when its struct device is released. Then > pci_bus_release_domain_nr() is called and accesses the freed > struct pci_bus. Reordering these fixes the issue. Since time log is not useful, remove it and just add stack trace. Change looks good to me. But I am not sure whether pci_remove_bus() directly frees struct pci_bus or just removes the bus resources? > > Fixes: c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()") > Reported-by: Jon Hunter > Tested-by: Jon Hunter > Cc: Pali Rohár > Signed-off-by: Rob Herring > --- > drivers/pci/remove.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c > index 0145aef1b930..22d39e12b236 100644 > --- a/drivers/pci/remove.c > +++ b/drivers/pci/remove.c > @@ -157,8 +157,6 @@ void pci_remove_root_bus(struct pci_bus *bus) > list_for_each_entry_safe(child, tmp, > &bus->devices, bus_list) > pci_remove_bus_device(child); > - pci_remove_bus(bus); > - host_bridge->bus = NULL; > > #ifdef CONFIG_PCI_DOMAINS_GENERIC > /* Release domain_nr if it was dynamically allocated */ > @@ -166,6 +164,9 @@ void pci_remove_root_bus(struct pci_bus *bus) > pci_bus_release_domain_nr(bus, host_bridge->dev.parent); > #endif > > + pci_remove_bus(bus); > + host_bridge->bus = NULL; > + > /* remove the host bridge */ > device_del(&host_bridge->dev); > } -- Sathyanarayanan Kuppuswamy Linux Kernel Developer