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Subject: Re: [PATCH 4.4 009/134] PCI/MSI: Stop disabling MSI/MSI-X in
 pci_device_shutdown()
From:   Ben Hutchings <ben.hutchings@codethink.co.uk>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Prarit Bhargava <prarit@redhat.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        David Arcari <darcari@redhat.com>,
        Myron Stowe <mstowe@redhat.com>,
        Lukas Wunner <lukas@wunner.de>,
        Keith Busch <keith.busch@intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Date:   Thu, 29 Mar 2018 16:28:54 +0100
In-Reply-To: <20180319171850.444128621@linuxfoundation.org>
References: <20180319171849.024066323@linuxfoundation.org>
         <20180319171850.444128621@linuxfoundation.org>
Organization: Codethink Ltd.
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On Mon, 2018-03-19 at 19:04 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Prarit Bhargava <prarit@redhat.com>
> 
> 
> [ Upstream commit fda78d7a0ead144f4b2cdb582dcba47911f4952c ]
[...]
> 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")

This went into 4.2 and hasn't been backported.

> and  e80e7edc55ba ("PCI/MSI: Initialize MSI capability for all
> architectures")

This went into 4.5 and hasn't been backported.

> changed the kexeced kernel to disable all MSIs itself so it no longer
> depends on the crashed kernel to clean up after itself.
[...]

So I think 3.18-stable and 4.4-stable will need backports of the later
changes in order for this to work properly.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.