From: Radu Rendec Date: Wed, 28 Nov 2018 03:20:48 +0000 (-0500) Subject: powerpc/msi: Fix NULL pointer access in teardown code X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=ee2bc807cbf0dfcf0f4ee522e3ca3d250c269158;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git powerpc/msi: Fix NULL pointer access in teardown code 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 --- diff --git a/arch/powerpc/kernel/msi.c b/arch/powerpc/kernel/msi.c index dab616a33b8d..f2197654be07 100644 --- a/arch/powerpc/kernel/msi.c +++ b/arch/powerpc/kernel/msi.c @@ -34,5 +34,10 @@ void arch_teardown_msi_irqs(struct pci_dev *dev) { 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); }