From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Bjorn Helgaas , Sinan Kaya Subject: [PATCH 4.9 09/17] ACPI / PCI: Bail early in acpi_pci_add_bus() if there is no ACPI handle Date: Tue, 7 Aug 2018 20:51:45 +0200 Message-Id: <20180807172342.641811274@linuxfoundation.org> In-Reply-To: <20180807172342.071526922@linuxfoundation.org> References: <20180807172342.071526922@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vitaly Kuznetsov commit a0040c0145945d3bd203df8fa97f6dfa819f3f7d upstream. Hyper-V instances support PCI pass-through which is implemented through PV pci-hyperv driver. When a device is passed through, a new root PCI bus is created in the guest. The bus sits on top of VMBus and has no associated information in ACPI. acpi_pci_add_bus() in this case proceeds all the way to acpi_evaluate_dsm(), which reports ACPI: \: failed to evaluate _DSM (0x1001) While acpi_pci_slot_enumerate() and acpiphp_enumerate_slots() are protected against ACPI_HANDLE() being NULL and do nothing, acpi_evaluate_dsm() is not and gives us the error. It seems the correct fix is to not do anything in acpi_pci_add_bus() in such cases. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Bjorn Helgaas Cc: Sinan Kaya Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci-acpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -567,7 +567,7 @@ void acpi_pci_add_bus(struct pci_bus *bu union acpi_object *obj; struct pci_host_bridge *bridge; - if (acpi_pci_disabled || !bus->bridge) + if (acpi_pci_disabled || !bus->bridge || !ACPI_HANDLE(bus->bridge)) return; acpi_pci_slot_enumerate(bus);