From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:47996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730483AbeLTJZp (ORCPT ); Thu, 20 Dec 2018 04:25:45 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Radu Rendec , Michael Ellerman Subject: [PATCH 4.14 14/72] powerpc/msi: Fix NULL pointer access in teardown code Date: Thu, 20 Dec 2018 10:18:13 +0100 Message-Id: <20181220085922.892730542@linuxfoundation.org> In-Reply-To: <20181220085922.332225035@linuxfoundation.org> References: <20181220085922.332225035@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Radu Rendec commit 78e7b15e17ac175e7eed9e21c6f92d03d3b0a6fa upstream. The arch_teardown_msi_irqs() function assumes that controller ops pointers were already checked in arch_setup_msi_irqs(), but this assumption is wrong: arch_teardown_msi_irqs() can be called even when arch_setup_msi_irqs() returns an error (-ENOSYS). This can happen in the following scenario: - msi_capability_init() calls pci_msi_setup_msi_irqs() - pci_msi_setup_msi_irqs() returns -ENOSYS - msi_capability_init() notices the error and calls free_msi_irqs() - free_msi_irqs() calls pci_msi_teardown_msi_irqs() This is easier to see when CONFIG_PCI_MSI_IRQ_DOMAIN is not set and pci_msi_setup_msi_irqs() and pci_msi_teardown_msi_irqs() are just aliases to arch_setup_msi_irqs() and arch_teardown_msi_irqs(). The call to free_msi_irqs() upon pci_msi_setup_msi_irqs() failure seems legit, as it does additional cleanup; e.g. list_del(&entry->list) and kfree(entry) inside free_msi_irqs() do happen (MSI descriptors are allocated before pci_msi_setup_msi_irqs() is called and need to be cleaned up if that fails). Fixes: 6b2fd7efeb88 ("PCI/MSI/PPC: Remove arch_msi_check_device()") Cc: stable@vger.kernel.org # v3.18+ Signed-off-by: Radu Rendec Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/msi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/powerpc/kernel/msi.c +++ b/arch/powerpc/kernel/msi.c @@ -34,5 +34,10 @@ void arch_teardown_msi_irqs(struct pci_d { struct pci_controller *phb = pci_bus_to_host(dev->bus); - phb->controller_ops.teardown_msi_irqs(dev); + /* + * We can be called even when arch_setup_msi_irqs() returns -ENOSYS, + * so check the pointer again. + */ + if (phb->controller_ops.teardown_msi_irqs) + phb->controller_ops.teardown_msi_irqs(dev); }