linux-kernel - Re: [PATCH 2/2] PCI: Disable PCIE hotplug interrupts early when msi is disabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z6HaYkIKLXji_EO7@wunner.de>
Date: Tue, 4 Feb 2025 10:14:10 +0100
From: Lukas Wunner <lukas@...ner.de>
To: Feng Tang <feng.tang@...ux.alibaba.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
	Jonathan Cameron <Jonthan.Cameron@...wei.com>,
	ilpo.jarvinen@...ux.intel.com, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] PCI: Disable PCIE hotplug interrupts early when msi
 is disabled

On Tue, Feb 04, 2025 at 01:37:58PM +0800, Feng Tang wrote:
> There was a irq storm bug when testing "pci=nomsi" case, and the root
> cause is: 'nomsi' will disable MSI and let devices and root ports use
> legacy INTX inerrupt, and likely make several devices/ports share one
> interrupt. In the failure case, BIOS doesn't disable the PCIE hotplug
> interrupts, and  actually asserts the command-complete interrupt.
> As MSI is disabled, ACPI initialization code will not enumerate root
> port's PCIE hotplug capability, and pciehp service driver wont' be
> enabled for the root port to handle that interrupt, later on when it is
> shared and enabled by other device driver like NVME or NIC, the "nobody
> care irq storm" happens.
> 
> So disable the pcie hotplug CCIE/HPIE interrupt in early boot phase when
> MSI is not enbaled.

So I think this issue should go away if disabling the interrupt
by portdrv is no longer conditional on

  (pcie_ports_native || host->native_pcie_hotplug)

like I've just proposed here:

  https://lore.kernel.org/r/Z6HYuBDP6uvE1Sf4@wunner.de/

... in which case this patch won't be necessary.  Can you confirm that?

You can split the change I've proposed into two patches if you like.

Thanks,

Lukas