From: Michael Ellerman <mpe@ellerman.id.au>
To: Bjorn Helgaas <helgaas@kernel.org>,
Amit Machhiwal <amachhiw@linux.ibm.com>,
Rob Herring <robh@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
kvm-ppc@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
Lizhi Hou <lizhi.hou@amd.com>,
Saravana Kannan <saravanak@google.com>,
Vaibhav Jain <vaibhav@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>,
Vaidyanathan Srinivasan <svaidy@linux.ibm.com>,
Kowshik Jois B S <kowsjois@linux.ibm.com>,
Lukas Wunner <lukas@wunner.de>,
kernel-team@lists.ubuntu.com,
Stefan Bader <stefan.bader@canonical.com>
Subject: Re: [PATCH v3] PCI: Fix crash during pci_dev hot-unplug on pseries KVM guest
Date: Thu, 15 Aug 2024 13:20:23 +1000 [thread overview]
Message-ID: <87h6bm1ngo.fsf@mail.lhotse> (raw)
In-Reply-To: <20240806200059.GA74866@bhelgaas>
Bjorn Helgaas <helgaas@kernel.org> writes:
> On Sat, Aug 03, 2024 at 12:03:25AM +0530, Amit Machhiwal wrote:
>> With CONFIG_PCI_DYNAMIC_OF_NODES [1], a hot-plug and hot-unplug sequence
>> of a PCI device attached to a PCI-bridge causes following kernel Oops on
>> a pseries KVM guest:
>
> What is unique about pseries here? There's nothing specific to
> pseries in the patch, so I would expect this to be a generic problem
> on any arch.
>
>> RTAS: event: 2, Type: Hotplug Event (229), Severity: 1
>> Kernel attempted to read user page (10ec00000048) - exploit attempt? (uid: 0)
>> BUG: Unable to handle kernel data access on read at 0x10ec00000048
>
> Weird address. I would expect NULL or something. Where did this
> non-NULL pointer come from?
It originally comes from np->data, which is supposed to be an
of_changeset.
The powerpc code also uses np->data for the struct pci_dn pointer, see
pci_add_device_node_info().
I wonder if that's why it's non-NULL?
Amit, do we have exact steps to reproduce this? I poked around a bit but
couldn't get it to trigger.
cheers
next prev parent reply other threads:[~2024-08-15 3:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-02 18:33 [PATCH v3] PCI: Fix crash during pci_dev hot-unplug on pseries KVM guest Amit Machhiwal
2024-08-06 20:00 ` Bjorn Helgaas
2024-08-13 16:43 ` Rob Herring
2024-08-15 3:20 ` Michael Ellerman [this message]
2024-08-16 12:43 ` Amit Machhiwal
2024-08-16 22:59 ` Michael Ellerman
2024-08-19 11:33 ` Amit Machhiwal
2024-08-13 16:44 ` Rob Herring (Arm)
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