From: Bjorn Helgaas <helgaas@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Guilherme G. Piccoli" <gpiccoli@canonical.com>,
linux-pci@vger.kernel.org, kexec@lists.infradead.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
bhelgaas@google.com, dyoung@redhat.com, bhe@redhat.com,
vgoyal@redhat.com, mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
andi@firstfloor.org, lukas@wunner.de, okaya@kernel.org,
kernelfans@gmail.com, ddstreet@canonical.com,
gavin.guo@canonical.com, jay.vosburgh@canonical.com,
kernel@gpiccoli.net, shan.gavin@linux.alibaba.com,
Eric Biederman <ebiederm@xmission.com>
Subject: Re: [PATCH 1/3] x86/quirks: Scan all busses for early PCI quirks
Date: Sat, 14 Nov 2020 14:39:25 -0600 [thread overview]
Message-ID: <20201114203925.GA1182595@bjorn-Precision-5520> (raw)
In-Reply-To: <87d00gltb9.fsf@nanos.tec.linutronix.de>
On Sat, Nov 14, 2020 at 12:40:10AM +0100, Thomas Gleixner wrote:
> Bjorn,
>
> On Sat, Nov 14 2020 at 00:31, Thomas Gleixner wrote:
> > On Fri, Nov 13 2020 at 10:46, Bjorn Helgaas wrote:
> >> pci_device_shutdown() still clears the Bus Master Enable bit if we're
> >> doing a kexec and the device is in D0-D3hot, which should also disable
> >> MSI/MSI-X. Why doesn't this solve the problem? Is this because the
> >> device causing the storm was in PCI_UNKNOWN state?
> >
> > That's indeed a really good question.
>
> So we do that on kexec, but is that true when starting a kdump kernel
> from a kernel crash? I doubt it.
Ah, right, I bet that's it, thanks. The kdump path is basically this:
crash_kexec
machine_kexec
while the usual kexec path is:
kernel_kexec
kernel_restart_prepare
device_shutdown
while (!list_empty(&devices_kset->list))
dev->bus->shutdown
pci_device_shutdown # pci_bus_type.shutdown
machine_kexec
So maybe we need to explore doing some or all of device_shutdown() in
the crash_kexec() path as well as in the kernel_kexec() path.
next prev parent reply other threads:[~2020-11-14 20:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-18 18:37 [PATCH 1/3] x86/quirks: Scan all busses for early PCI quirks Guilherme G. Piccoli
2018-10-18 18:37 ` [PATCH 2/3] x86/PCI: Export find_cap() to be used in early PCI code Guilherme G. Piccoli
2018-10-18 18:37 ` [PATCH 3/3] x86/quirks: Add parameter to clear MSIs early on boot Guilherme G. Piccoli
2018-10-18 20:08 ` Sinan Kaya
2018-10-18 20:13 ` Guilherme G. Piccoli
2018-10-18 20:30 ` Sinan Kaya
2018-10-22 19:44 ` Guilherme G. Piccoli
2018-10-18 22:15 ` [PATCH 1/3] x86/quirks: Scan all busses for early PCI quirks Bjorn Helgaas
2018-10-22 20:35 ` Guilherme G. Piccoli
2018-10-23 17:03 ` Bjorn Helgaas
2020-11-06 13:14 ` Guilherme G. Piccoli
2020-11-13 16:46 ` Bjorn Helgaas
2020-11-13 23:31 ` Thomas Gleixner
2020-11-13 23:40 ` Thomas Gleixner
2020-11-14 20:39 ` Bjorn Helgaas [this message]
2020-11-14 20:58 ` Thomas Gleixner
2020-11-14 21:22 ` Bjorn Helgaas
2020-11-15 14:05 ` Eric W. Biederman
2020-11-15 14:29 ` Eric W. Biederman
2020-11-15 15:11 ` Thomas Gleixner
2020-11-15 17:01 ` Lukas Wunner
2020-11-15 19:18 ` Thomas Gleixner
2020-11-15 20:46 ` Eric W. Biederman
2020-11-16 20:31 ` Guilherme G. Piccoli
2020-11-16 21:45 ` Eric W. Biederman
2020-11-16 21:49 ` Guilherme Piccoli
2020-11-17 0:19 ` Bjorn Helgaas
2020-11-17 1:06 ` Eric W. Biederman
2020-11-17 9:53 ` Thomas Gleixner
2020-11-17 12:19 ` David Woodhouse
2020-11-17 19:34 ` Thomas Gleixner
2020-11-17 22:25 ` Eric W. Biederman
2020-11-17 12:04 ` Guilherme Piccoli
2020-11-18 21:05 ` Bjorn Helgaas
2020-11-18 22:36 ` Guilherme Piccoli
2020-11-30 20:20 ` Bjorn Helgaas
2020-12-14 18:32 ` Guilherme Piccoli
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