linux-kernel - Re: [PATCH] PCI/pwrctrl: Only destroy alongside host bridge

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Message-ID: <aHgmzpNzMTL2alhp@google.com>
Date: Wed, 16 Jul 2025 15:25:18 -0700
From: Brian Norris <briannorris@...omium.org>
To: Manivannan Sadhasivam <mani@...nel.org>
Cc: Bartosz Golaszewski <brgl@...ev.pl>,
	Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
	Rob Herring <robh@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI/pwrctrl: Only destroy alongside host bridge

On Wed, Jul 16, 2025 at 09:47:41AM -0700, Brian Norris wrote:
> (2) Even after resolving 1, I'm seeing pci_free_host_bridge() exit with
>     a bridge->dev.kboj.kref refcount of 1 in some cases. I don't yet
>     have an explanation of that one.

Ah, well now I have an explanation:
One should always be skeptical of out-of-tree drivers.

In this case, one of my endpoint drivers was mismanaging a pci_dev_put()
reference count, and that cascades to all its children and links,
including the host bridge.

Once I fix that (and the aforementioned problem (1)), it seems my
problems go away.

I'll let a v2 soak in my local environment, and unless I hear some news
from Bartosz about OF_POPULATED to change my mind, I'll send it out
eventually.

Brian