This is a note to let you know that I've just added the patch titled
PCI/MSI: Stop disabling MSI/MSI-X in pci_device_shutdown()
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: pci-msi-stop-disabling-msi-msi-x-in-pci_device_shutdown.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Mar 19 09:58:12 CET 2018
From: Prarit Bhargava prarit@redhat.com Date: Thu, 26 Jan 2017 14:07:47 -0500 Subject: PCI/MSI: Stop disabling MSI/MSI-X in pci_device_shutdown()
From: Prarit Bhargava prarit@redhat.com
[ Upstream commit fda78d7a0ead144f4b2cdb582dcba47911f4952c ]
The pci_bus_type .shutdown method, pci_device_shutdown(), is called from device_shutdown() in the kernel restart and shutdown paths.
Previously, pci_device_shutdown() called pci_msi_shutdown() and pci_msix_shutdown(). This disables MSI and MSI-X, which causes the device to fall back to raising interrupts via INTx. But the driver is still bound to the device, it doesn't know about this change, and it likely doesn't have an INTx handler, so these INTx interrupts cause "nobody cared" warnings like this:
irq 16: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.2-1.el7_UNSUPPORTED.x86_64 #1 Hardware name: Hewlett-Packard HP Z820 Workstation/158B, BIOS J63 v03.90 06/ ...
The MSI disabling code was added by d52877c7b1af ("pci/irq: let pci_device_shutdown to call pci_msi_shutdown v2") because a driver left MSI enabled and kdump failed because the kexeced kernel wasn't prepared to receive the MSI interrupts.
Subsequent commits 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI") and e80e7edc55ba ("PCI/MSI: Initialize MSI capability for all architectures") changed the kexeced kernel to disable all MSIs itself so it no longer depends on the crashed kernel to clean up after itself.
Stop disabling MSI/MSI-X in pci_device_shutdown(). This resolves the "nobody cared" unhandled IRQ issue above. It also allows PCI serial devices, which may rely on the MSI interrupts, to continue outputting messages during reboot/shutdown.
[bhelgaas: changelog, drop pci_msi_shutdown() and pci_msix_shutdown() calls altogether] Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=187351 Signed-off-by: Prarit Bhargava prarit@redhat.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com CC: Alex Williamson alex.williamson@redhat.com CC: David Arcari darcari@redhat.com CC: Myron Stowe mstowe@redhat.com CC: Lukas Wunner lukas@wunner.de CC: Keith Busch keith.busch@intel.com CC: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/pci-driver.c | 2 -- 1 file changed, 2 deletions(-)
--- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -463,8 +463,6 @@ static void pci_device_shutdown(struct d
if (drv && drv->shutdown) drv->shutdown(pci_dev); - pci_msi_shutdown(pci_dev); - pci_msix_shutdown(pci_dev);
#ifdef CONFIG_KEXEC_CORE /*
Patches currently in stable-queue which might be from prarit@redhat.com are
queue-4.4/pci-msi-stop-disabling-msi-msi-x-in-pci_device_shutdown.patch