From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755131AbbCXR0i (ORCPT ); Tue, 24 Mar 2015 13:26:38 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:60328 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754887AbbCXR0c (ORCPT ); Tue, 24 Mar 2015 13:26:32 -0400 X-Sasl-enc: idNFlR03ZaZ1QSXeY0HnKj5lwKecWk1QXXRJPzLPI1rj 1427217991 Date: Tue, 24 Mar 2015 18:02:11 +0100 From: Greg KH To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Bjorn Helgaas , linux-pci@vger.kernel.org, Fam Zheng , Yinghai Lu Subject: Re: [PATCH v3 00/10] pci: fix unhandled interrupt on shutdown Message-ID: <20150324170211.GA1989@kroah.com> References: <1427211032-2270-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427211032-2270-1-git-send-email-mst@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 24, 2015 at 04:42:25PM +0100, Michael S. Tsirkin wrote: > Fam Zheng noticed that pci shutdown disables msi and msix of a device while > device is still active. This was intended to fix kexec with fusion devices but > had the unintended effect of breaking even regular shutdown when using virtio. > > As a result, people reported VMs being hung on shutdown, > with traces that look like this: > > ... > > [] ? _raw_spin_unlock_irqrestore+0x1b/0x40 > [] pci_bus_read_config_word+0x9f/0xb0 > [] pci_read_config_word+0x1c/0x20 > [] pci_intx+0x33/0xb0 > [] pci_msix_shutdown+0x8d/0x90 > [] pci_device_shutdown+0x46/0x60 > [] device_shutdown+0xc8/0x180 > [] kernel_power_off+0x35/0x80 > [] SYSC_reboot+0x18b/0x260 > [] ? d_free+0x55/0x60 > [] ? mntput+0x24/0x40 > [] ? __fput+0x183/0x270 > [] SyS_reboot+0xe/0x10 > [] system_call_fastpath+0x16/0x1b > > ... > > as well as the messages that look like this: > BUG: soft lockup - CPU#2 stuck for 22s! [poweroff:1964] > > The same problem would affect any driver which doesn't register > a level interrupt handler when using msix. > > I think the fix is to avoid touching device on shutdown: > we clear bus master anyway, so we won't get any more > msi interrupts, and bus reset will clear the msi/msix > state eventually. > > The patch that added the code in question is from > d52877c7b1afb8c37ebe17e2005040b79cb618b0: > "pci/irq: let pci_device_shutdown to call pci_msi_shutdown v2" > from 2008, but it turns out that in 2011 the following commit > commit d5dea7d95c48d7bc951cee4910a7fd9c0cd26fb0 > "PCI: msi: Disable msi interrupts when we initialize a pci device" > fixed the issue in a more robust way. The only thing left to do is to > fix configurations with CONFIG_PCI_MSI disabled, and then > d52877c7b1afb8c37ebe17e2005040b79cb618b0 can be reverted. > > Status: > > Patches 1-6 work well for me. > Given they affect all pci devices, and the bug has been there since 2.6 times, > I think there's no rush: we can merge them for 4.1. > > At the same time, once merged, patches 1-4 will likely make a good stable > candidate. > > Patches 7-10 compiled only, will need maintainer ack. > > Please review, and consider at least 1-6 for 4.1. > > Changes from v3: > move code from probe to device enumeration > add patches to unexport pci_msi_off > > Michael S. Tsirkin (10): > pci: export functions for msi/msix ctrl > pci: move pci_msi_init_pci_dev to pci.c > pci: drop some duplicate code > pci: don't disable msi/msix at shutdown > pci: make msi/msix shutdown functions static > virtio_pci: drop msi_off on probe > ntb: drop pci_msi_off call on probe > mic: drop pci_msi_off call on probe > pci: drop pci_msi_off calls from quirks > pci: unexport pci_msi_off > > drivers/pci/pci.h | 25 +++++++++++++-- > include/linux/pci.h | 5 --- > drivers/misc/mic/host/mic_intr.c | 2 -- > drivers/ntb/ntb_hw.c | 2 -- > drivers/pci/msi.c | 62 ++++++++------------------------------ > drivers/pci/pci-driver.c | 2 -- > drivers/pci/pci.c | 26 ++++------------ > drivers/pci/probe.c | 16 ++++++++++ > drivers/pci/quirks.c | 2 -- > drivers/virtio/virtio_pci_common.c | 3 -- > 10 files changed, 57 insertions(+), 88 deletions(-) This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read Documentation/stable_kernel_rules.txt for how to do this properly.