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 A7C31C76196 for ; Thu, 6 Apr 2023 23:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230426AbjDFXYm (ORCPT ); Thu, 6 Apr 2023 19:24:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229575AbjDFXYl (ORCPT ); Thu, 6 Apr 2023 19:24:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B653F72BC; Thu, 6 Apr 2023 16:24:40 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 535D264D6C; Thu, 6 Apr 2023 23:24:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77DEFC433EF; Thu, 6 Apr 2023 23:24:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1680823479; bh=+L+QKD/FQo0MgxvLbghtNeLPq4hqP/ZxmEizXwHvvFE=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=dLEdr8mk/YGGKf8ESvJ/SaUIV+FaeZq/4eIfBfY4xb2pFaULsDDjV6d0eOuMmrNFp 3/iTywStMlwtb/h2fARO0tQaKRDc9UyP0b21QiWfUzmQBooEZC8HOtlPS7A7UmuvxF Ga6iN0Vnqiws607R7EGWVi7JJ24ml5LiEwqMjlPZZEH8FuT16qBVnqeeg3Fg4ynLFf z9/VIV4hMnzRaYw64ZwwaO3PUtDsC4hk8MtHAf5Wo8UwNAng4U3V447GUhwwAlNGKg z55Yl19o/hUSXiU7cTBo7kHg35zC9KOcECPTC7UCBTdvQQuGjAA5JxO5jufsv7QEHj NIFZLfdDiHHxw== Date: Thu, 6 Apr 2023 18:24:37 -0500 From: Bjorn Helgaas To: Rob Herring Cc: Bjorn Helgaas , Pali =?iso-8859-1?Q?Roh=E1r?= , Jon Hunter , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI: Fix use-after-free in pci_bus_release_domain_nr() Message-ID: <20230406232437.GA3749012@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230329123835.2724518-1-robh@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Mar 29, 2023 at 07:38:35AM -0500, 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. > > 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 Applied to for-linus for v6.3, thanks! I also added a stable tag since c14f7ccc9f5d appeared in v6.2. > --- > 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); > } > -- > 2.39.2 >